Poultry diets may be formulated to identical nutrient specifications, yet their biological performance can differ markedly due to one often-overlooked factor: feed structure. This first part explores how particle size distribution influences digestive physiology, gizzard development, gut health and feeding behaviour, demonstrating why particle size should be regarded not merely as a milling parameter, but as a critical nutritional characteristic that bridges feed manufacturing and animal performance.

Poultry feed formulation has reached a high level of precision, yet differences in bird performance persist despite identical nutrient specifications. Increasing evidence suggests that these discrepancies are not explained solely by nutrient composition, but also by feed structure, particularly particle size distribution.

This paper examines how grinding, mixing, handling, and pelleting shape feed structure and, in turn, influence digestive physiology, gut health, nutrient utilization, and feeding behavior in poultry. Particular attention is given to particle size distribution—not only its average value, but its overall profile—and its role in feed homogeneity, segregation, and digestive function.

The effects of pelleting on particle size are discussed, together with the need for appropriate measurement methods in finished feeds. Finally, the paper advocates a more integrated approach in which particle size is defined, measured, and managed as a nutritional parameter. Emerging tools for real-time monitoring and process control are highlighted as key enablers of this transition.

Ultimately, particle size should be viewed not as a by-product of grinding, but as a functional feed attribute that must be aligned with nutritional objectives.

ONE FORMULA, TWO OUTCOMES
Two feed mills may produce the same broiler diet on paper, using identical ingredient compositions and meeting the same nutrient and energy specifications. Yet, under commercial conditions, bird performance can differ substantially. Broilers fed from one mill may achieve faster growth, convert feed more efficiently, and superior gastrointestinal development compared with those receiving feed from the other mill. The difference lies not in the formulation matrix itself, but in the extent of feed processing and the resulting physical structure of the finished feed.

Modern poultry nutrition is built on precision. Nutritionists formulate diets to meet biological requirements with increasing accuracy, while feed technologists design processes to ensure throughput, efficiency, and pellet quality. Both disciplines ultimately pursue the same objective: delivering nutrients to the animal in the most effective way. Yet between formulation and feeding, a critical transformation occurs. During grinding, mixing, conditioning, and pelleting, feed is not only processed—it is structurally redefined.

This transformation governs how nutrients are accessed, digested, and utilized by the bird. It shapes how feed is perceived, selected, retained, and broken down in the gastrointestinal tract. Feed structure, and particularly particle size distribution, thus emerges as the missing link between what is formulated and what is biologically expressed.

Despite its importance, this link remains insufficiently integrated into both nutritional formulation and feed manufacturing practices. Particle size is still too often treated as a secondary parameter, reduced to equipment settings or a single analytical value. This paper explores how particle size reduction and feed processing shape both technological outcomes and biological responses and argues for a more integrated approach in which particle size is considered a functional parameter of nutrition.

DEFINING FEED PARTICLE SIZE
Feed particle size (PS) is often reduced, in practice, to a single number: the median diameter, commonly expressed as D50. While useful, this simplification hides a much richer reality. Particle size is not a single point, but a distribution. Two feeds with the same D50 may behave very differently in the animal if one contains a high proportion of fine particles and the other a wider spread including coarse fractions.

Understanding particle size therefore requires moving beyond a single value and considering the full particle size distribution, including its shape, its extremes, and its consistency over time. Characterizing this distribution requires a standardized series of sieves. A set including 100, 200, 500, 800, 1000, 1600, 2000, and 3150 µm provides a practical framework for describing feed granulometry. Beyond D50, the geometric standard deviation (GSD), which reflects dispersion, together with the proportion of each particle fraction, are essential descriptors of feed structure.

From a processing perspective, the properties of the raw materials set the starting particle size. Milling then reduces these particles to smaller sizes, so the final particle size is determined by the milling operation. Depending on plant design, ingredients may be ground together after dosing (post-grinding) or individually before mixing (pre-grinding), the latter offering greater flexibility to tailor particle size distributions to nutritional objectives.

Particle size is shaped primarily by the choice of grinding technology and operating conditions. Hammer mills generally produce broader distributions with a higher proportion of fines, whereas roller mills generate more uniform particles with fewer fines. Beyond equipment selection, screen size, tip speed, throughput, specific energy input, and equipment wear all influence the final distribution. Raw material properties such as hardness, moisture content, fiber structure, and fat level further contribute to grinding behavior and particle size variability.

Targeting a lower D50 generally requires higher specific energy input and is frequently accompanied by a greater proportion of fines and increased dispersion within the particle size distribution. Consequently, particle size should not be viewed solely through its average value, but through the overall balance between mean size, distribution width, and process efficiency.

Particle size is therefore a measurable, traceable, and repeatable technological outcome. When properly defined and monitored, it becomes a genuine feed quality attribute, comparable to pellet durability or moisture content. More than a by-product of grinding, it is a parameter that can be deliberately targeted, controlled, and optimized.

THE ANIMAL’S PERSPECTIVE
During feed manufacturing, most ingredients, particularly cereal grains, are ground prior to incorporation into the final diet. Grinding reduces particle size and alters the physical characteristics of ingredients, improving blending ability and homogeneity, reducing segregation during handling, and facilitating the pelleting process. Particle size reduction is also believed to enhance the accessibility of digestive enzymes to substrates due to the increased surface area of feed particles. However, excessively fine particles may adversely affect the development and functionality of the foregut, particularly the proventriculus and gizzard, which play a critical role in regulating intestinal health and nutrient utilisation. Feeding coarser particles has been associated with improved foregut development, enhanced gut motility, and better digestive function, contributing to overall gut health. Nevertheless, results from studies evaluating the effects of feed particle size on upper gastrointestinal tract development remain inconsistent. These discrepancies are largely attributed to confounding factors, particularly feed form (mash vs. pellets), which can mask or modify the biological effects of particle size.

The influence of feed particle size on gizzard development is well documented. The gizzard possesses a remarkable capacity to mechanically reduce feed particles to a relatively uniform size, regardless of initial particle dimensions. Early work by O’Dell et al. (1959) demonstrated that birds fed purified diets composed predominantly of fine particles exhibited an enlarged proventriculus and a reduced gizzard size compared with birds fed diets containing coarser particles. Diets consisting of fine particles were also shown to pass more rapidly through the gastrointestinal tract (135 vs. 165 minutes). Additionally, birds consuming finely ground diets exhibited increased water intake, likely to facilitate feed ingestion, resulting in a pendulous crop. These observations highlight the physiological consequences of excessive particle size reduction on foregut function.

Hetland et al. (2002) demonstrated in broilers that, irrespective of the original feed structure, the majority of digesta particles measured less than 0.04 mm in diameter upon leaving the gizzard. These findings highlight the gizzard’s critical role in regulating particle size before digesta enters the small intestine. Gizzard weight in broilers is positively correlated with feed particle size when diets are offered in mash form. Broilers fed mash diets containing coarsely ground particles exhibit prolonged digesta retention time in the gizzard, leading to enhanced gizzard development. Increased grinding activity within the gizzard stimulates hypertrophy of the gizzard musculature, which is characterized by well-developed myelinated muscle fibres (Figure 1).

Enhanced gizzard function has been associated with increased pancreatic enzyme secretion, mediated in part by elevated cholecystokinin release (Svihus, 2014), as well as improved gastrointestinal tract motility. A well-developed gizzard generates stronger reverse peristaltic contractions, thereby enhancing the mechanical breakdown of feed and promoting increased proteolysis by pepsin, trypsin, and other endogenous proteases in the small intestine. Gabriel et al. (2003) reported that the inclusion of larger feed particles enhanced pepsin activity in the proventriculus, reinforcing the role of feed particle size in modulating digestive enzyme activity and protein digestion efficiency. Collectively, these physiological adaptations contribute to more efficient digestion and improved nutrient utilisation (Figure 2).

A well-developed gizzard also plays a critical role in regulating gastrointestinal microbial ecology by acting as a physiological barrier against pathogenic bacteria entering the distal gastrointestinal tract. Enhanced gizzard function is associated with increased hydrochloric acid secretion and lower pH in the digestive tract, creating an antimicrobial environment that suppresses acid-sensitive pathogens. Studies have shown that birds fed coarse mash diets exhibit increased populations of beneficial Lactobacillus spp. in the caeca, whereas finely ground and pelleted diets are associated with reduced lactic acid bacteria counts. Increased inclusion of coarse particles has also been linked to higher Lactobacillus and Bifidobacterium populations and reduced counts of pathogenic or opportunistic bacteria such as Clostridium, Campylobacter, and Bacteroides spp. In contrast, finely ground feed particles pass more rapidly through the gizzard, limiting exposure to acidic conditions and proteolytic enzymes. The resulting influx of undigested material into the small intestine may promote dysbiosis and facilitate the proliferation of pathogens such as Clostridium perfringens and Escherichia coli. Collectively, these findings suggest that feed particle size influences gut microbiota through two primary mechanisms: enhanced antimicrobial action mediated by a functional gizzard and the promotion of competitive exclusion via increased colonisation of commensal bacteria.

Poultry are highly sensitive to feed particle size and can distinguish textural differences through mechanoreceptors in the beak from an early age. Birds consistently show a preference for larger particles, and this preference intensifies as they mature. Feed particle size, together with dietary nutrient density, is a primary determinant of voluntary feed intake (FI), with numerous studies demonstrating that changes in particle size alone, without altering diet composition, can significantly influence FI in poultry. Feed selection behaviour further indicates that birds preferentially consume coarse particles, leaving behind fines, underscoring feed particle size as a key driver of feeding behaviour and intake regulation in poultry.

Studies evaluating the effects of feed particle size on FI in broilers fed mash diets have produced inconsistent results, largely due to the influence of multiple confounding factors, including grain type and cultivar, endosperm hardness, particle size characteristics (mean size, uniformity, and distribution), grinding method, and bird age. Amerah et al. (2007) reported that broilers fed coarsely ground wheat mash diets (7-mm screen) consumed approximately 13% more feed than those fed medium-ground diets (3-mm screen), resulting in significant improvements in weight gain and feed efficiency. Yasar (2003) demonstrated that the negative effects of soluble non-starch polysaccharides (NSP) in wheat-based diets were exacerbated by fine grinding. Reducing screen size from 7.0 to 6.0, 5.0, and 4.0 mm progressively increased ileal digesta viscosity (from 7.3 to 18.3 cP), which was associated with reduced FI. This effect was attributed to increased solubilisation of NSP following fine grinding, leading to slower digesta passage rate and consequent suppression of feed intake. Nir et al. (1994) demonstrated that, irrespective of cereal type (maize, wheat, or sorghum), mash diets with a medium particle size, corresponding to a GMD of 966–1266 μm, resulted in the highest FI and optimal growth performance.

However, when diets are pelleted or crumbled, differences in pre-pelleting particle size often result in similar broiler performance outcomes. This convergence in performance is largely attributed to the pelleting process, which tends to homogenize particle size distribution, effectively minimizing structural differences created by grinding intensity (Abdollahi et al., 2011). Particle size reduction during pelleting is thought to occur because larger particles are preferentially fractured under the compressive forces generated by the narrow gap between pellet rollers and the die, as well as the frictional forces within the die channels.

It is noteworthy that the optimal feed microstructure may vary with bird age. During the starter phase, broilers are assumed to have an incompletely developed gizzard, which may limit their tolerance for large feed particles compared with later grow-out phases. Several studies have reported negative effects of high inclusion levels of coarsely ground maize particles in mash diets fed to young birds, an effect commonly attributed to the limited grinding capacity of an immature gizzard. In contrast, when diets are provided in pelleted form, even during the starter phase, broilers exhibit a high tolerance for coarse particles. These findings indicate that pelleting process largely mitigates the negative effects of coarse particles observed in mash diets and allows the inclusion of coarser grains even in young broilers. Therefore, and based on the available literature, responses observed in broilers fed mash diets differing in particle size cannot be directly extrapolated to pelleted or crumbled diets, as particle size differences are largely reduced during the pelleting process. In broilers fed pelleted or crumbled diets, the inclusion of coarsely ground grain does not appear to depress FI and may, in fact, improve feed utilisation. From a feed manufacturing perspective, coarse grinding offers additional advantages, including substantial energy savings with wider grinder screen openings and increased mill throughput.

References are available upon request.

About Dr. Reza Abdollahi
Dr. Reza Abdollahi is currently affiliated with the Monogastric Research Centre, at Massey University as an Adjunct Professor of Poultry Nutrition. He is also the founder of “A2Z Poultry Feed DynamikZ”, an international independent research and consultancy firm. Dr Abdollahi is a globally recognized poultry nutrition expert with over 28 years of experience across academia, research, and industry, with an extensive track record in feed formulation, nutrient utilisation, and commercial poultry performance optimisation.

About Marc Perel
An engineer specializing in feed manufacturing technologies, Marc Perel is the founder of FeedSphere Solutions©, an independent consulting firm serving the global animal nutrition industry. With more than 30 years of international experience and projects spanning over 400 production sites in 45 countries, he provides expert guidance on feed manufacturing, process optimization, and industrial performance, helping companies implement practical, unbiased solutions tailored to their operational needs.

The importance of feed particle size: From milling efficiency to gizzard function – Part I yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Whilst non-starch polysaccharide-degrading enzymes have been around for over 35 years, we are still learning about their potential benefits. One area of current interest is the production of xylo-oligosaccharides. This article looks at what we currently know and its potential implications.

Let us start by reminding ourselves what we mean by a prebiotic. The International Scientific Association for Probiotics and Prebiotics (ISAPP) defines prebiotics as “a substrate that is selectively utilized by host microorganisms, conferring a health benefit.”

So, we can think of prebiotics as foods or stimuli that support the success of “beneficial” micro-organisms in the gut of our animals, at the same time suppressing the opportunities for “non-beneficial” micro-organisms to thrive.

When we add enzymes, such as ENZY Carboplus, to combat non-starch polysaccharides (NSP), the resulting breakdown products include fragments of the targeted NSPs referred to as xylo-oligosaccharides (XO). For example, in most cases the NSP here is arabinoxylan, or AX (Figure 1). Figure 1 also indicates the bonds between monomers that are disrupted by β-1,4 xylanase enzymes.

The resulting XOs vary in size and depending upon the region of cleaved bonds, the chain length may be as short as 2 monomers, to as long as 8. This difference in size is termed as the degree of polymerization (DP); this is used to classify the XOs as High DP (longer chains) or LP (shorter chains).

HOW DO XO ACTUALLY HELP?
There has been a lot of work over the last 10 years on modes of action, and much work is still required; but there are two main threads to this work.
1. As fermentation substrates, utilisable by the enteric microbiota
2. As stimulants (“stimbiotics”) to increase microbial activity and ability to use carbohydrates

Trials with commercial livestock have shown the benefits of XOs:
• Feed Conversion Ratio (FCR): Over a range of studies in broilers, FCR improvement is fairly consistent, with an average improvement of around 10%. In some challenge trials (Ren 2024, Cao 2025) FCR improvements are even greater, where the comparison is between a challenged control and addition of XO.

• Bodyweight Gain (BWG) shows less consistent improvements, but slightly higher at 9% – for example, an increase in average daily weight gain from 63 g to 68 g, potentially reducing grow-out period by 2 days.

• There appears to be a beneficial effect on intestinal architecture and integrity. In several trials, villus height increases and crypt depth declines, indicating better potential nutrient absorption with lower energy expenditure on enterocyte replenishment. Additionally, when experiments have looked at gene expression of tight junction proteins, these are often significantly up-regulated, suggesting a more secure intestinal structure.

• Inflammation and oxidative stress might also be improved, with some limited trials showing reductions in markers such as malonaldehyde (MDA), Interleukin 6 (IL-6), and Tumour Necrosis Factor α (TNF-α).

Many of these trials have been conducted with added XO products. These are manufactured from various vegetable materials, and result in products with variable – and usually unmeasured – degree of polymerization. In these studies, the inclusion levels of these products ranged from 0.15 g up to 30 g per kg of feed. This, in turn, resulted in a varied concentration of active xylo-oligosaccharides ranging from 0.019 g to 21 g/kg of feed!

CAN WE APPLY THIS KNOWLEDGE TO ENZYME APPLICATIONS?
If we consider a broiler diet based on wheat and soya, we can calculate the potential XO release by ENZY Carboplus as follows:

This means the potential supply of XO from an effective carbohydrase enzyme like Carboplus can be up to ten times higher than levels used in trials that showed beneficial results.

The answer is therefore, yes: we can apply such knowledge to enzyme applications.

THIS SHINES A LIGHT ON THE BENEFITS SEEN IN MAIZE-BASED DIETS
This concept also answers a fundamental question about NSP-degrading enzymes: why are they still effective when used in a maize-based diet? For all enzymes to be effective, they must have a substrate to work upon; and the level of the substrate is one of the factors that determines the value of an enzyme. The NSP content of maize is a lot lower than that for wheat.

Total NSP content for maize is typically 30% lower than for wheat. Even more striking is the soluble NSP content – over 55% lower. Our understanding of the detrimental effect of NSPs is that a lot of the problem comes from increased viscosity, which is directly related only to the soluble portion. We would therefore expect improvements in performance in maize-based diets to be proportionately less.

However, now that we understand that a significant portion of improvements come from a prebiotic effect, we can begin to appreciate why – even in diets based on maize – we can expect considerably greater improvements in performance, or an appreciable allocation of nutrient sparing capacity.

VARIATION IN XO STRUCTURE
It was previously mentioned that the structure of XO is variable. When the NSP enzyme cleaves the arabinoxylan structure along the xylan “backbone”, it results in fragments that vary in size, from only two xylose molecules linked together up to eight or more. The larger XO are said to have a higher degree of polymerization (DP). Do these differences have an impact on their ability to function as prebiotics?

Research in the field is scarce. Ren et al. (BMC Microbiology,2025) conducted in-vitro trials based on collected broiler caecal contents. This culture medium was then used to test the ability of XO with varying degrees of polymerization to resist the impact of avian pathogenic Escherichia coli (APEC). Bacterial population evenness (Pielou index) was significantly reduced by APEC, whilst application of all XO treatments improved evenness. Diversity was improved by all XO treatments, compared to APEC challenge. The treatment with the highest DP – X4, xylotetraose – enhanced levels of Bifidobacterium very significantly, whilst X3, xylotriose was most effective at increasing butyric acid levels. Both of these factors are associated with “improved” gut environment.

Wallace et al. (Animal Nutrition 2026) used extracts from commercial XO products to produce low DP (X2, X3) and high DP (X4 and above) test materials, fed at 150 g / tonne of feed (Figure 2). When fed to broilers to 35 days of age using a diet based on wheat, barley and sorghum, the results shown in Table 2 were obtained.

Additionally, there were differences in bacterial populations in the ileal digesta and excreta. Here, the low DP containing diet showed a significant increase in Enterobacteriaceae. This is of potential concern, as this large family of Gram-negative bacteria contains the potential pathogens Salmonella and Escherichia coli.

It appears the birds responded more favourably to higher DP XO additions. The authors theorise that this may be due to a “stimbiotic” effect – that is, XO act as signaling molecules, stimulating fibre-degrading microbiota to increase extracellular enzyme production.

SUMMARY AND THE WAY FORWARD
What does all of this mean for our conventional approach of adding NSP-degrading enzymes to broiler diets? In addition to the well-known effects of reducing digesta viscosity and disrupting the “cage effect”, we now see the potential of the break-down products of arabinoxylan disruption to act as stimulators and modulators of hind gut fermentation. In turn, this leads to enhanced performance and – potentially – enhanced protection against pathogens such as APEC, Salmonella and Clostridia.

More work is clearly required to confirm the potential of this approach, and the preferred degree of polymerization of XO. Once this is established, research then needs to be conducted to quantify the XO classifications arising from application of different xylanase products.

About Martin Smith
Scientific Product Manager, Enzymes at Kaesler Nutrition GmbH, Martin Smith is a practicing commercial nutritionist, with extensive knowledge across a wide range of additives and their impact on animal performance, health and welfare.

Beyond viscosity: The prebiotic mechanism of xylanase enzymes in poultry yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

The European Citizens’ Initiative “End the Cage Age” marks a major turning point for farming in Europe. Faced with growing societal and regulatory pressure, phasing out cages is no longer just a possibility. It is a shared goal that all stakeholders must work towards. For the rabbit industry, transitioning to alternative systems requires rethinking production models. The main challenge? Balancing the expression of the animals’ natural behaviours with maintaining zootechnical and economic performance, while managing environmental stress. In this complex equation, precision nutrition stands out as an essential strategic tool.

Animal welfare is defined as “the physical and mental state of an animal in relation to the conditions in which it lives and dies”. According to the World Organisation for Animal Health, this concept is based on the “Five Freedoms”, which include:
• freedom to express normal behaviour for its species;
• freedom from fear and distress;
• freedom from physical and/or thermal stress;
• freedom from pain, injury and disease;
• freedom from hunger, thirst and malnutrition.

Therefore, nutrition plays a central role. It must constantly adapt to housing and environmental conditions to preserve health and ensure optimal welfare.

THE “CAGE-FREE” CHALLENGE: BALANCING NATURAL BEHAVIOURS AND ZOOTECHNICAL PERFORMANCE
The European Citizens’ Initiative (ECI) “End the Cage Age” gathered nearly 1.4 million signatures. This prompted the European Commission to make a ban on cages a legislative priority for 2026. Rather than just undergoing these changes, the French rabbit industry has been proactive. It has engaged in a collaborative approach, setting an ambitious goal: to reach 30% alternative housing for fattening rabbits by 2030.

A. Undeniable behavioural benefits
New housing methods (parks, floor pens with or without outdoor access) aim to improve rabbits’ ability to express natural behaviours. Studies conducted by TECHNA⁽¹⁾ confirm the positive impact of these floor systems (Figure 1) on behavioural welfare. Although resting remains the rabbit’s main activity (about 66% of the time), animals raised in alternative systems move around significantly more. Moving time increases from 4.8% in conventional cages to 6.2% in parks, and up to 13% in floor pens with outdoor access. Furthermore, there is a notable reduction in stereotypic behaviours. For instance, excessive grooming, considered a response to an unstimulating environment, is seen in 16% of caged rabbits, compared to an average of only 7% in alternative systems. Rabbits can also stand on their hind legs more easily, directly reflecting their behaviour in the wild (Figure 2).

B. The zootechnical and health dilemma
However, the core challenge of transitioning to cage-free systems lies in maintaining farm performance. Despite the behavioural benefits, TECHNA’s studies and field feedback highlight real difficulties. Increased physical activity in group parks leads to lower growth performance. This results in a tendency towards lower body weights and a worsened feed conversion ratio, assuming the diet remains the same. Health risks are also higher because the group effect increases contagion and the frequency of digestive issues. Additionally, hygiene becomes more complex. Managing cleaning and disinfection protocols is harder in pens, which helps pathogens survive. For the nutritionist, a successful transition therefore relies on a multi-criteria approach, combining animal welfare, technical performance, and economic viability.

MANAGING FARM CONDITIONS: PREVENTING HEAT STRESS TO ENSURE RABBIT WELFARE
Evaluating welfare goes beyond the size of the enclosure. It involves knowing how to manage farms in all conditions, especially when facing climate hazards. This means respecting the freedom from thermal stress.

The rabbit is highly sensitive to heat. It struggles metabolically as soon as the temperature exceeds 26°C. We can even see early signs of poorer performance at more moderate temperatures, starting from 21°C. A TECHNA study⁽²⁾ showed a 22% drop in feed intake when the average temperature rose from 19°C to 25°C in maternity (Figure 3). This caused lower growth rates in young rabbits, a loss of body condition in females, and a higher health risk. Relative air humidity makes things worse by changing the temperature actually felt by the animals. For example, 35°C combined with 100% relative humidity is much harder to tolerate than 40°C with only 20% humidity. Even in closed, well-equipped buildings (with fans and cooling systems), fine-tuning temperature and humidity remains difficult.

PRECISION NUTRITION: THE SCIENTIFIC
LINK BETWEEN WELFARE
AND RABBIT PERFORMANCE
In this context of major challenges (cage-free systems, climate hazards, health pressures), precision nutrition stands out as a vital strategic tool. At TECHNA, this approach is built on three main pillars (Figure 4).

Pillar 1: Fibre Expertise, The Foundation of Digestive Safety
In rabbit farming, nearly half of all health issues are digestive (bacteria, viruses, dysbiosis, stress). These can lead to high mortality rates. Controlled starch and protein levels are necessary, but the role of fibre is absolutely crucial for the health of the caecum, the main reservoir in the rabbit’s digestive tract. Research by TECHNA, recognised as an expert in rabbit fibre nutrition, shows the importance of balancing two main types of fibre:

• Indigestible fibres (cellulose and lignin): Barely digested, they act as a mechanical “sweeper”. They reduce the time feed spends in the digestive tract, preventing the growth of harmful bacteria and the build-up of gas. They are vital for reducing diarrhoea symptoms.

• Digestible fibres (hemicelluloses and pectin): Used as a substrate by the gut flora, they are fermented and produce volatile fatty acids (VFAs), which provide energy for the rabbit. This fermentation lowers the caecal pH, creating a hostile environment for pathogens. They are particularly effective in reducing paresis (stoppage of the digestive transit).

This expertise also involves maintaining a strict balance between these two types of fibre during formulation. This is achieved mainly by using the Digestible Fibre / ADF ratio⁽³⁾. This scientific expertise is directly applied through Lapilest. This raw material was specifically designed by TECHNA to make rabbit feed safer, while keeping things simple for the feed manufacturer.

Pillar 2: Dynamic Formulation and Adaptive Feeding Strategies
Precision nutrition means adapting specifications to different physiological stages and farming contexts. This aligns nutritional intake with the animals’ needs. To do this, it relies on fine-tuning raw material matrices based on the results of strict quality control plans.

• Matrices: Technical and economic safety goes beyond simply checking raw materials and finished products (nutritional and hygiene criteria). TECHNA’s added value for its feed manufacturer clients lies in the dynamic, real-time adjustment of their formulation matrices. This is done notably using Black Box, a dedicated tool for creating raw material matrices. Regularly adapting the matrices guarantees absolute nutritional consistency. This is essential for stabilising the rabbit’s digestive system, which is sensitive to major changes in the feed formula.

• Adapted feed specifications: The shift to group parks, along with climate change, alters the rabbits’ needs. They are more active and eat less feed. TECHNA includes these new variables when formulating diets. These specifications help offset the increase in energy expenditure or the drop in feed intake, while managing digestive risks.

• Adjusted feeding programmes: TECHNA supports feed manufacturers in designing tailor-made feeding programmes and distribution plans. These are adapted to the farm’s constraints and goals, as well as health conditions and genetics. TECHNA’s deep understanding of rabbit feeding behaviour allows it to perfectly tailor its feeding recommendations.

Pillar 3: Functional Supplementation, A Key Lever for Health Prevention
Phasing out cages and increasing flock sizes in floor parks undeniably raise infection pressures. More frequent heatwaves also put a heavy strain on the animals’ bodies. In this context, beyond basic nutrition, the strategic use of feed additives is the third fundamental pillar for ensuring farm viability.

To help the industry face these challenges, TECHNA’s scientific approach relies on providing targeted functional solutions.

• Controlling the digestive and parasitic ecosystem: The rise in parasites is strongly linked to higher floor densities. Controlling health issues therefore requires dedicated nutritional strategies. This is exactly the goal of specialised product ranges like Suriance and Rabiance, designed to limit these risks.

• Physiological support against environmental stress: Because animals are more exposed, particularly to heat stress, using liver protectors, antioxidants, electrolytes, or respiratory tract protectors is highly recommended to maintain homeostasis.

• Strengthening overall immunity: Optimising immune status and improving the herd’s general resistance complete this preventive approach. Solutions like Imun’up or Kaoline perfectly illustrate this commitment to supporting the animal’s natural defences against new environmental stresses.

CONCLUSION
“End the Cage Age” is a shift that should drive innovation across the whole rabbit industry. To meet this major challenge, the approach must move away from standard models and become holistic. It must combine rigorous on-farm welfare assessments – using reference tools like EBENE® – with complete scientific control of farming practices and nutritional levers. By rolling out its expertise in precision nutrition (fibre balance, adjusted matrices), farming techniques (feeding methods), and natural health (dedicated additives), TECHNA is committed to helping its manufacturing clients improve sustainable performance. In the future, success will belong to those who can turn environmental and societal challenges into opportunities for progress. This will ensure animal health, the economic viability of the industry, and comfortable daily working conditions for farmers.

Bibliography:
(1) Study of the fattening rabbit behavior according to four housing systems, Rebours et al., WRC, 2024
(2) Effets de la température ambiante sur les consommations d’aliment et les performances en maternité, Vastel et al., JRC, 2025
(3) Effets du rapport entre fibres digestibles et indigestibles dans l’aliment sur la santé digestive et les performances des lapins en engraissement, Rebours et al., JRC, 2019

About Paméla Vastel
Holding an engineering degree in Animal Production, Paméla Vastel has dedicated her career to the rabbit sector across its entire supply chain, active within bodies like ASFC, WRC, JRC, and CLIPP. Following field experience in feed manufacturing, she has been a Rabbit Specialist at TECHNA for 16 years. She leverages her expertise to provide feed mills with tailored solutions driving performance, economic profitability, animal welfare, and the long-term sustainability of the rabbit industry.

Animal welfare in rabbit farming: Meeting the “cage-free” challenge through precision nutrition yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Heat stress remains a major challenge in broiler production, compromising performance, immunity, and welfare. As gut health is closely linked to animal resilience, nutritional strategies based on olive bioactives — rich in antioxidant and anti-inflammatory compounds — are emerging as promising tools to help broilers better cope with high temperatures.

HEAT STRESS: A MAJOR CHALLENGE IN BROILER PRODUCTION
Modern broilers are genetically selected for rapid growth and high feed efficiency. However, this also makes them particularly sensitive to thermal stress. Under hot environmental conditions, birds reduce feed intake in an attempt to decrease metabolic heat production. As a consequence, growth rate declines, feed conversion worsens, and immune competence may become compromised.

At the same time, heat stress increases oxidative stress and inflammatory responses, negatively affecting gut integrity, welfare and meat quality. As global temperatures continue to rise, the poultry industry is increasingly searching for practical and sustainable nutritional strategies capable of improving bird resilience under challenging conditions.

OLIVE BIOACTIVES AS FUNCTIONAL
FEED ADDITIVES
Olive oil industry by-products are rich in a wide range of bioactive compounds, including polyphenols, flavonoids, secoiridoids, and triterpenic acids such as hydroxytyrosol, oleuropein, and maslinic acid. These olive bioactives are well known for their antioxidant, anti-inflammatory, antimicrobial, and hepatoprotective properties. In animal nutrition, they are increasingly valued for their ability to support gut integrity, immune function, oxidative balance, and overall animal robustness. In addition to their functional benefits, olive bioactives also contribute to more sustainable and circular production systems through the valorization of agro-industrial by-products.

EVALUATING OLIVE BIOACTIVES UNDER HEAT STRESS CONDITIONS
A recent study conducted by Kasetsart University (Thailand) in collaboration with Lucta evaluated the effects of olive bioactives (OBs) on broiler chickens raised under heat stress conditions. The research investigated not only growth performance, but also immune parameters, intestinal integrity, animal welfare indicators, and meat quality characteristics. The objective was to determine whether OBs could improve bird performance and resilience under heat stress conditions with and without the presence of salinomycin.

The trial involved 1,000 one-day-old male Ross 308 broilers exposed to high ambient temperatures and humidity throughout the experimental period. Animals were distributed in 4 experimental treatments with ten replicates each (25 birds/replicate) using a 2 × 2 factorial design with two levels of OBs (0 or 1,200 ppm) and two levels of salinomycin (SAL; 0 or 66 ppm). Feed and water were provided ad libitum for 40 days. Temperature-humidity index values remained above 80 during most of the study, confirming significant heat stress conditions.

BETTER PERFORMANCE UNDER
CHALLENGING CONDITIONS
One of the most relevant findings was the positive effect of OBs on broiler growth performance, independently of the presence of salinomycin. Birds receiving OBs showed higher body weight and body weight gain compared to the control group (Figure 1a), with no changes in feed intake, resulting in lower feed conversion ratio during the overall period (Figure 1b). Moreover, mortality of the birds receiving OBs was significantly lower (Figure 1c).

SUPPORTING IMMUNE BALANCE
Heat stress not only affects performance but also disrupts immune homeostasis. In poultry, the heterophil-to-lymphocyte ratio (H/L ratio) is widely used as an indicator of physiological stress. Higher H/L ratios generally reflect elevated stress and inflammatory status. Broilers supplemented with OBs reduced H/L ratios compared to the non-supplemented group (2.28 vs 2.63, P < 0.01). These findings indicate improved immune balance.

WELFARE BENEFITS: FEWER FOOTPAD LESIONS
Footpad dermatitis is one of the most relevant welfare indicators in broiler production and is often associated with litter quality and digestive disturbances. In this study, birds receiving OBs showed fewer footpad lesions.

IMPROVING MEAT QUALITY NATURALLY
One of the most interesting aspects of olive bioactives is their impact on meat quality. Broilers supplemented with OBs showed lower drip loss (Figure 2a) and reduced lipid oxidation in breast meat (TBARS, Figure 2b). From a commercial perspective, this means improved water-holding capacity, better oxidative stability, and potentially longer shelf life. The study also reported increases in mono- and polyunsaturated fatty acids in birds supplemented with olive pomace extract. This suggests potential benefits not only for animal resilience but also for the nutritional value of poultry meat.

CONCLUSIONS
Olive bioactives show strong potential as a natural nutritional strategy to help broilers better cope with heat stress. By supporting performance, immune balance, welfare, and meat quality, these compounds may contribute to more resilient and sustainable poultry production systems.

Source: Adapted from Philatha et al., 2026 (Poultry Science 105:106266)

About Dr. Marta Blanch
Dr. Marta Blanch holds a PhD in Animal Production (2009) and a degree in Veterinary Medicine (2003) from the Universitat Autònoma de Barcelona. She brings nearly 20 years of experience in livestock nutrition, gained through her work in both public research institutions and the private industry. She has been part of Lucta since 2016 and currently serves as Innovation Poultry and Ruminants Team Leader, leading research and innovation activities focused on the development of novel feed additives for animal production. Her main areas of expertise include palatability, gut health, production efficiency, and animal welfare, with a strong focus on translating scientific knowledge into practical, innovative, and market-oriented solutions for the livestock industry.

Olive bioactives: Helping broilers beat the heat yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Heat stress is often seen as a temperature problem — but the real damage happens at the cellular level. When thermal load increases, oxidative stress builds faster than the animal’s natural defenses can respond, quietly undermining gut integrity, immunity and overall performance. Addressing this requires more than cooling systems. Trace minerals — copper, zinc, manganese and selenium — are the essential building blocks of the antioxidant enzyme network that protects animals from the inside out.

Heat stress does not destroy performance directly. It destroys the cellular infrastructure that makes performance possible. Behind every measurable outcome, declining growth, fragile gut integrity, compromised fertility, reduced egg quality, lies a common mechanism: oxidative damage. When thermal load rises, reactive oxygen species accumulate faster than the animal’s antioxidant defenses can neutralize them. This results in membrane damage, tight junction dysfunction and reduced immune functioning. Heat stress today is no longer a seasonal risk: rising temperatures, high-performing genetics and year-round production pressure have made this cellular threat a structural reality in animal production worldwide. Managing the temperature is necessary but managing the oxidative damage is where the final outcome is actually decided.

Modern production systems intensify the challenge, and climate control alone is not enough. As ambient temperature rises, animals activate mechanisms to reduce internal heat load: respiration rate increases, panting intensifies and blood flow is redirected toward the skin (Figure 1). These thermoregulatory responses come at a cost of energy diverted from growth, egg production and milk yield, declining feed intake, and compromised gut and immune function. Performance losses are the visible outcome, but the real damage is already unfolding at the cellular level.

THE REAL BOTTLENECK: OXIDATIVE PRESSURE AT CELLULAR LEVEL
Oxidative stress does not wait for extreme heat events. It builds progressively as feed intake drops, metabolism shifts and low‑grade inflammation sets in. Importantly, oxidative stress is not limited to heat alone, it may also arise during transport, disease challenges or periods of reduced feed intake, conditions that often coincide with high environmental temperatures. Effective strategies to counter it are not optional, they are essential to preserve resilience.

Heat stress mitigation works best in 3 steps:
1. Reduce external heat load (ventilation, cooling systems, water availability).
2. Support metabolic stability via nutrition (energy density, electrolytes, vitamins).
3. Protect at cellular level, where Cu, Zn, Mn and L‑selenomethionine power the antioxidant enzymes that neutralize oxidative damage.

Management interventions form the first line of defense, helping to lower the external thermal burden. Yet these measures alone cannot fully protect animals once metabolic and inflammatory processes are activated internally. Nutritional strategies should therefore be applied, to take over at the cellular level. While energy, electrolytes and vitamins traditionally receive most attention during hot periods, trace minerals operate quietly at the core of cellular protection, because without them, the antioxidant enzyme network cannot run at full capacity precisely when oxidative pressure is highest.

One of the most damaging consequences of heat stress is the overproduction of reactive oxygen species (ROS). When ROS generation exceeds the animal’s antioxidant capacity, oxidative stress occurs, triggering lipid peroxidation, protein oxidation and DNA damage.

COPPER, ZINC AND MANGANESE: POWERING THE SUPEROXIDE DISMUTASE (SOD) SYSTEM
Trace minerals do not neutralize free radicals the way vitamins do. Instead, they serve as essential cofactors of antioxidant enzymes and without adequate supply, these enzymes simply cannot function. Copper (Cu), zinc (Zn) and manganese (Mn) are integral to the superoxide dismutase (SOD) enzyme family. SOD enzymes form the first line of defense against oxidative stress by converting superoxide radicals into hydrogen peroxide:
• Cu/Zn-SOD functions in the cytosol and extracellular fluids,
• Mn-SOD operates inside mitochondria, where oxidative pressure is highest.

During heat stress, mitochondrial ROS production increases sharply, making adequate manganese supply particularly important. Suboptimal levels of Cu, Zn or Mn reduce SOD activity, leaving tissues vulnerable to oxidative damage precisely when protection is most needed.

During heat stress, the gastrointestinal tract becomes a critical bottleneck for mineral nutrition. Feed intake declines, gastric pH shifts and intestinal permeability increases, all of which limit mineral absorption. At the same time, metabolic demand for antioxidant enzymes rises sharply. This creates a physiological paradox: animals require more trace minerals precisely when their ability to absorb them is compromised. Under such conditions, not only the inclusion level, but especially the chemical form and stability of trace minerals, becomes decisive.

Modern trace mineral technologies, such as Excential SMART hydroxy trace minerals, are specifically designed to address this challenge. Hydroxy forms of copper, zinc and manganese possess unique physicochemical properties that make them particularly effective during periods of thermal stress (Figure 2). Unlike inorganic sulphates, hydroxy trace minerals are poorly soluble at neutral pH and therefore remain largely intact in the upper digestive tract. This limits premature dissociation and reduces unwanted interactions with other dietary components such as phytate, vitamins or unsaturated lipids.

By remaining stable until they reach the acidic environment of the stomach, hydroxy trace minerals allow for a more controlled release of Cu, Zn and Mn at the main sites of absorption. This controlled release is especially important during heat stress, when intestinal integrity is often compromised. Elevated temperatures and oxidative pressure weaken tight junctions, increasing sensitivity to irritation and the risk of pro oxidant reactions in the gut lumen. Due to their lower reactivity, hydroxy trace minerals exert less oxidative pressure locally, helping to preserve gut barrier function, an essential prerequisite for maintaining nutrient uptake and immune competence under thermal challenge.

Beyond gastrointestinal stability, hydroxy trace minerals also contribute to more consistent tissue availability of copper, zinc and manganese. Even when feed intake is reduced, this reliable delivery supports the activity of key antioxidant enzymes, helping to safeguard cellular defense systems at a time when oxidative pressure is highest.

SELENIUM: CORNERSTONE OF LIPID PROTECTION
If copper, zinc and manganese form the first enzymatic barrier against oxidative stress, selenium acts as the final safeguard, protecting the most vulnerable structures in the cell: its membranes. During heat stress, this role becomes indispensable.

Rising body temperature inevitably leads to increased generation of hydrogen peroxide and lipid hydroperoxides. These reactive compounds are particularly damaging to cell membranes, which are rich in polyunsaturated fatty acids and highly sensitive to oxidative attack. Once lipid peroxidation is initiated, membrane integrity, transport functions and cellular signaling rapidly deteriorate. The consequences, impaired gut function, weakened immunity, compromised fertility compound quickly.

Selenium plays a unique role in preventing this cascade (Figure 3). Incorporated into selenoproteins such as glutathione peroxidases (GPx), selenium enables the detoxification of hydrogen peroxide and lipid hydroperoxides before they can damage cell membranes. During heat stress, when lipid oxidation pressure is high, the demand for GPx activity increases sharply, making selenium supply a critical limiting factor in antioxidant defense. However, heat stress also challenges selenium nutrition itself. Reduced feed intake directly lowers selenium intake, while gastrointestinal disturbances can impair absorption. Under these conditions, the form in which selenium is supplied becomes decisive.

L‑selenomethionine is the form of selenium found most in nature, and it stands out because it behaves differently from inorganic or other organic selenium sources. Unlike selenite or selenocysteine‑based forms, L‑selenomethionine can be non‑specifically incorporated into body proteins in place of methionine. In effect, it creates a physiological selenium reserve. This reserve becomes especially valuable during heat stress. Even when dietary intake drops, selenium stored in body proteins can be gradually released through normal protein turnover, ensuring a continuous supply for vital selenoprotein synthesis. In this way, L‑selenomethionine acts as a nutritional buffer, bridging periods of reduced intake while antioxidant demand remains high.

Research consistently demonstrates that animals receiving selenium predominantly as L‑selenomethionine show improved antioxidant status, more stable immune responses and better performance under thermal stress. By safeguarding membrane integrity and supporting redox balance at the cellular level, selenium does not merely mitigate the symptoms of heat stress, it strengthens the animal’s capacity to cope with it. Excential Selenium 4000, providing all selenium as L‑selenomethionine, is specifically designed to deliver this level of protection. By combining immediate functional availability with the ability to build selenium reserves, it helps maintain antioxidant defense precisely when animals are most vulnerable.

The biological relevance of this mechanism is not only theoretical; it translates into measurable outcomes under heat stress. In a broiler study conducted at Ghent University (Belgium), a control diet containing sodium selenite was compared with a control diet supplemented with organic selenium in the form of Excential Selenium 4000. From day 28 onwards, birds were subjected to heat stress during the finisher period. Under these conditions, supplementation with Excential Selenium 4000 resulted in a significant improvement in feed conversion ratio (FCR), showing a 14% reduction. In addition, a numerical increase in body weight gain was observed. These results demonstrate that organic selenium can effectively mitigate the negative impact of heat stress on broiler performance. Another study, by Jayasri et al. (2022) demonstrates that heat stress markedly increases oxidative stress and cellular stress markers such as HSP 70 and PGC 1α. Dietary supplementation with organic selenium (L selenomethionine) significantly reduced lipid peroxidation and moderated the heat shock response, indicating improved cellular resilience during thermal challenge.

The underlying mechanism for these effects, grounded on selenoproteins that function to protect membranes, is conserved across species, making the principle equally relevant for layers, swine and dairy cattle facing thermal challenge.

BIOAVAILABILITY BECOMES NON-NEGOTIABLE UNDER STRESS
Oxidative stress is one of the defining production challenges of modern animal agriculture. When the right trace minerals are available in the most optimal form, the animal’s own enzymatic defenses can do what no management intervention alone can: protect at the cellular level.

Animals require more trace minerals exactly when their ability to absorb them is compromised.

Copper, zinc, manganese and selenium play irreplaceable roles in the enzymatic antioxidant defense network that protects animals at the cellular level. Heat stress combines two critical challenges: reduced feed intake and increased metabolic demand for antioxidant protection. Under these conditions, mineral source and bioavailability become decisive. Poorly available inorganic trace minerals may fail to meet tissue requirements when intake is compromised. In contrast, highly bioavailable sources ensure that antioxidant enzymes remain functional even at lower inclusion levels. This is particularly relevant for selenium, copper and zinc, where source form strongly influences tissue retention and functional availability during stress.

As global temperatures rise and production intensity increases, the question is no longer whether trace minerals matter under heat stress, it is whether the forms you use can deliver when it counts. Bioavailability is no longer a formulation detail, it is a production decision with measurable consequences. When the right trace minerals reach the right tissues at the right time, cellular defense holds. That is what it means to put the science in your feed.

Heat stress is the trigger: Oxidative damage is the real threat yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Overall, the results of this study indicate that in addition to improving feed efficiency and 48-day processing yields, dietary Arg may also influence core body temperature in a dose-dependent manner in broilers subjected to a cyclic HS challenge. This may be due to the role of Arg in vasodilation and the alleviation of oxidative stress.

Arginine (Arg) is an amino acid considered to be essential for poultry and conditionally essential for humans. Due to its metabolic role in the regulation of health and growth, it is considered a “functional” amino acid that has extensive metabolic roles beyond protein synthesis and accretion (Wu, 2009; Castro and Kim, 2020). Specifically, Arg is a precursor for the synthesis of many molecules including nitric oxide, proline, hydroxyproline, polyamines, glutamine, ornithine, and creatine (Khajali and Wideman, 2010). Therefore, it is involved in many important biological and physiological roles including immune function, wound healing, vasodilation, and alleviation of oxidative stress (Wideman et al., 1995; Murrell et al., 1997; Atakisi et al., 2009; D’Amato and Humphrey, 2010; Khajali and Wideman, 2010; Fouad et al., 2012).

Heat stress (HS) is a common environmental stressor that results in substantial negative effects on animal welfare, growth performance, and carcass characteristics (Geraert et al., 1996; Sandercock et al., 2001; Song and King, 2015; Rostagno, 2020), and significant economic losses to the global broiler industry. Heat stress occurs when the amount of heat energy produced by the animal exceeds the amount of net energy being dissipated from the animal’s body (Lara and Rostagno, 2013). Genetic selection of modern broiler genotypes has made them more sensitive to elevated temperatures, which has been suggested in part due to increased metabolic activity that causes a greater production of body heat (Settar et al., 1999; Lara and Rostagno, 2013). Nutritional manipulation is one of the several management strategies that can be used to help alleviate this condition.

Arg has previously been shown to influence the performance of birds subjected to HS, with higher ratios improving FCR and increasing breast meat yield. Brake et al. (1994a,b) suggested that the dietary Arg requirement during hot temperatures may be higher compared to at ambient temperatures because Arg availability from dietary sources is decreased, or its metabolic requirement is increased, or both. Decreased availability may be caused bychanges in gut morphology and integrity, amino acid absorption, or intestinal microbiota, while an increased metabolic requirement could be caused by higher production of reactive oxygen species and a higher level of lipid peroxidation that occurs in heat-stressed chickens (Brake et al., 1998; Yang et al., 2010; Rostagno, 2022). With these mechanisms in mind, the application of Arg to ameliorate the effects of HS and improve broiler growth performance has gained strong interest from the poultry industry.

METHODS
Male Ross 708 broiler chicks were weighed by group to determine the average overall body weight and allotted to 48 floor pens. All pens contained used pine litter top-dressed with fresh shavings and were equipped with a single commercial-type pan feeder and nipple waterers to provide free access to feed and clean water throughout the trial. Supplemental waterers and chick pan feeders were placed in each pen from 0 to 7 d post-hatch to facilitate access to feed and water for young chicks. Broilers were fed diets in four phases that included a common starter phase (0 – 17 d), a common grower phase (17 – 27 d), an experimental finisher 1 phase (27 – 38 d), and an experimental finisher 2 phase (38 – 46 d). Diets were formulated using ingredients that were analyzed prior to formulation in order to achieve target amino acid concentrations. The common starter and common grower diets were corn and soybean meal-based and formulated to meet or exceed the primary breeder nutrient recommendations. The finisher 1 and finisher 2 formulations were designed to be nutritionally complete and meet primary breeder recommendations except for Arg concentration. Six dietary treatments of digestible Arg: Lys ratios of 80, 92, 104, 116, 128, 140 were utilized. The starter diets were pelleted and crumbled, while the other diets were fed as pellets. Barn temperature was set to 32°C and decreased gradually throughout the trial to maintain bird comfort. On d 28, a cyclic HS program was employed where barn temperature was maintained at 32°C for 12 h daily (7:30 h to 19:30 h) and reduced to 24°C each night. This model was intended to mimic the cyclic HS experienced naturally by birds in the field, and was successful in inducing moderate HS as indicated by increased panting, modified bird behavior (leg extension), and increased core body temperature during each daily rise in barn temperature. Core body temperature was measured by cloacal temperature readings taken at 32, 39, and 46 d at both 6:00 h (before daily heat was applied) and 14:00 h (during peak daily heat application). Feeder and bird pen weights were recorded at 0, 17, 27, 38, and 46 d to determine growth performance, body weight, body weight gain (BWG), feed intake (FI), and mortality-corrected feed conversion ratio (FCR) for each feeding phase and cumulatively. Feed intake was calculated based on number of bird days to account for mortality. At the end of the trial, eight birds per pen were randomly selected, wing-banded, and marked for processing at 48 d at the Fortenberry Processing Plant at the Charles C. Miller Poultry Research Center at Auburn University. After an overnight chill, carcasses were deboned to collect weights of the pectoralis major (P. major) and minor (P. minor) muscles, wings, thighs, and drums. Total breast meat was calculated as the sum of the P. major and P. minor weights, and the yield of each part was determined by division of the part weight by the individual live weight taken the afternoon before the day of processing.

RESULTS
During both finisher 1 and finisher 2 phases, feed conversion ratio improved linearly (P = 0.001 and 0.012, respectively) as the ratio of Arg:Lys in the diet increased. Core body temperature increased by 1.6°C on average from readings taken prior to daily heat application (6:00 h) and at peak daily temperature (14:00 h) (Table 1). At both 32 and 39 d, 14:00 h core body temperature exhibited a quadratic relationship (P = 0.022 and 0.021, respectively) with dietary Arg, with the lowest numerical temperature observed for birds fed the diet with 116 Arg. At 46 d, the relationship between body temperature and Arg decreased linearly (P = 0.011) with a trend towards a quadratic relationship (P = 0.087).

Increasing Arg:Lys ratio in the diet resulted in several statistically significant responses in processing characteristics (Table 2). Chilled carcass weight exhibited a quadratic (P = 0.034) relationship with Arg level while chilled carcass yield exhibited a linear (P = 0.006) increase. In addition, both breast fillet weight and yield had a quadratic (P = 0.007 and 0.018, respectively) relationship with increasing Arg, with the numerically highest weight and yield achieved with the Arg:Lys ratio of 128 and 116, respectively. Tender weight showed a quadratic (P = 0.040) relationship with Arg as well, numerically increasing up to the Arg ratio of 128. Tender yield linearly (P = 0.038) increased with dietary Arg:Lys ratio. As expected with these responses in both breast fillets and tenders, total breast weight and yield also exhibited quadratic (P = 0.009 and 0.023, respectively) relationships with Arg, reaching the numerically highest values of 0.837 kg and 26.82% at Arg:Lys ratios of 128 and 116, respectively. Drum yield decreased quadratically (P = 0.031) as Arg ratio increased, presumably at the benefit of breast meat. The lowest numerical value for drum yield was measured at an Arg ratio of 128.

DISCUSSION
The Arg:Lys ratio recommended by the primary breeder to optimize growth performance for as-hatched Ross broilers is 108 from 25 – 39 d (finisher 1 phase) and 110 from 40 – 51 d (finisher 2 phase) (Aviagen Inc., 2022). The titration used in the current study captured a range of Arg:Lys ratios well below and above these values. In our study, the fact that FCR improved in a linear fashion as Arg ratio increased in conditions of cyclic HS suggests that FCR may have been optimized at Arg ratios greater than 140. Previous studies have also reported similar trends where increased Arg in the diet was associated with improved FCR during HS conditions. For example, Mendes et al. (1997) reported that FCR decreased from 1.955 to 1.912 when broilers were fed 110 and 140 Arg:Lys, respectively, from 21 to 42 d. Brake et al. (1998) showed a significant improvement in FCR between heat-stressed broilers fed a 136 ratio of Arg:Lys compared to a 109 ratio that was not significant between thermoneutral controls. Alternatively, Chamruspollert et al. (2004) reported a quadratic relationship of FCR with Arg for 7 to 21 d old chicks raised in constant HS as the dietary ratio increased in six increments of Arg:Lys ratio from 79 to 121.

Although we saw a linear improvement in feed efficiency as Arg:Lys ratio increased, there was no response to Arg in body weight gain. Though there was no thermoneutral control in our current trial, it is a reasonable hypothesis that the cyclic HS muted some of the effects of Arg on weight gain and that Arg was prioritized for other metabolic functions beyond muscle protein synthesis to ameliorate the effects of HS. Brake et al. (1998) noticed only a numerical increase in weight gain between two groups of 20 to 41 d old birds fed a diet of 109 or 136 Arg:Lys and subjected to HS, while a significant increase was observed between the two groups of thermoneutral controls. Conversely, a study by Chamruspollert et al. (2004) reported a quadratic relationship of BWG with increasing Arg ratios of 79 to 121, but this was determined in 7 to 21 d-old chicks reared in constant 35°C HS.

Cloacal temperature measurements taken in the current study show that dietary Arg:Lys ratio can influence the broiler’s ability to regulate body temperature under conditions of HS. Additionally, the quadratic response at 32 and 39 d compared with the linear response at 46 d suggests that the requirement to facilitate optimal thermoregulation may change with age. Arg likely influences body temperature through its role as a precursor to nitric oxide, a primary regulator of cutaneous vasodilation and blood flow (Moncada and Higgs, 1993; Steiner and Branco, 2001).

Dietary Arg level has also been shown to have effects on processing characteristics, most commonly influencing breast meat yield, leg meat yield, and carcass abdominal fat (Fouad et al., 2012). However, the influence of Arg level on processing characteristics during HS is less well documented. Still, some researchers have shown improved breast meat yield with increased Arg even when broilers were subjected to HS during the growing period (Mahmoud et al., 1996; Esser et al., 2017). Under thermoneutral conditions, the increase in breast meat yield has been shown to be at least in part at the expense of wing yield (Al-Daraji and Salih, 2012). In the current study, we found no influence on wing yield but rather a decrease in drum yield as dietary Arg and breast meat yield increased. Identifying processed parts that are either maximized or minimized in yield at certain Arg:Lys ratios can help producers make decisions to balance profit with cost of feed.

CONCLUSION
These data demonstrate that feed conversion and processing characteristics of Ross 708 male broilers are responsive to dietary Arg under cyclic HS conditions. Core body temperature was also influenced by Arg:Lys ratio under HS at each time point measured, providing evidence of metabolic roles of Arg beyond protein synthesis and accretion (i.e., vasodilation and alleviation of oxidative stress).

References
1. A l-Daraji, H. J., and A. M. Salih. 2012. Effect of dietary L-arginine on carcass traits of broilers. Res. Opin. Anim. Vet. Sci. 2:40 – 44.
2. Atakisi, O., E. Atakisi, and A. Kart. 2009. Effects of dietary zinc and l-arginine supplementation on total antioxidants capacity, lipid peroxidation, nitric oxide, egg weight, and blood biochemical values in Japanese quails. Biol. Trace Elem. Res. 132:136 – 143.
3. Aviagen Inc. 2022. ROSS Broiler: Nutrition Specifications. Aviagen, Huntsville, AL.
4. Brake, J., D. Balnave, and J. J. Dibner. 1994a. Wide arginine:lysine ratio ameliorates effect of heat stress in broilers. Poult. Sci. 73:74 – 82.
5. Brake, J., D. Balnave, and J. J. Dibner. 1998. Optimum dietary arginine:lysine ratio for broiler chickens is altered during heat stress in association with changes in intestinal uptake and dietary sodium chloride. Br. Poult. Sci. 39:639 – 647.
6. Brake, J., P. Ferket, J. Grimes, D. Balnave, I. Gorman, and J. J. Dibner. 1994b. Optimum arginine:lysine ratio changes in hot weather. Pages 82-104 in Proc. 21st Annu. Caroli na Poult. Nutr. Conf. North Carolina State University, Raleigh, NC.
7. Castro, F. L. D. S., and W., K. Kim. 2020. Secondary functions of arginine and sulfur amino acids in poultry health. Animals. 10:2106.
8. Chamruspollert, M., G. M. Pesti, and R. I. Bakalli. 2004. Influence of temperature on the arginine and methionine requirements of young broiler chicks. J. Appl. Poult. Res. 13:628 – 638.
9. D’Amato, J. L., and B. D. Humphrey. 2010. Dietary arginine levels alter markers of arginine utilization in peripheral blood mononuclear cells and thymocytes in young broiler chicks. Poult. Sci. 89:938 – 947.
10. Esser, A. F. G., D. R. M. Gonçalves, A. Rorig, A. B. Cristo, R. Perini, and J. I. M. Fernandes. 2017. Effects of guanidionoacetic acid and arginine supplementation to vegetable diets fed to broiler chickens subjected to heat stress before slaughter. Rev. Bras. Cienc. Avic. 19:429 – 436.
11. Fouad, A. M., H. K. El-Senousey, X. J. Yang, and J. H. Yao. 2012. Role of dietary l-arginine in poultry production. Int.J. Poult. Sci. 11:718-729.
12. Geraert, P. A., J. C. F. Padilha, and S. Guillaumin. 1996. Metabolic and endocrine changes induced by chronic heat xposure in broiler chickens: growth performance, body composition and energy retention. Br. J. Nutr. 75:195 – 204.
13. K hajali, F., and R. F. Wideman. 2010. Dietary arginine: Metabolic, environmental, immunological and physiological interrelationships. Worlds Poult. Sci. J. 66:751 – 766.
14. Kidd, M. T. 2004. Nutritional modulation of immune function in broilers. Poult. Sci. 83:650 – 657.
15. Lara, L. J., and M. H. Rostagno. 2013. Impact of heat stress on poultry production. Animals. 3:356 – 369.
16. Mahmoud, H. A., R. C. Teeter, and M. N. Makled. 1996. Arginine:lysine ratio effects on performance and carcass variables of broilers reared in thermoneutral and heat stress environments. Poult. Sci. 75:88.
17. Mendes, A. A., S. E. Watkins, J. A. England, E. A. Saleh, A. L Waldroup, and P. W. Waldroup. 1997. Influence of dietary lysine levels and arginine:lysine ratios on performance of broilers exposed to heat or cold stress during the period of three to six weeks of age. Poult. Sci. 76:472 – 478.
18. Moncada, S., and A. Higgs. 1993. The L-arginine-nitric oxide pathway. N. Engl. J. Med. 329:2002-2012.
19. Murrell, G. A., C. Szabo, J. A. Hannafin, D. Jang, M. M. Dolan, X. H. Deng, D. F. Murrell, and R. F. Warren. 1997.
20. Modulation of tendon healing by nitric oxide. Inflamm. Res. 46:19 – 27.
21. Rostagno, M. 2020. Effects of heat stress on the gut health of poultry. J. Anim. Sci. 98:1 – 9.
22. Sandercock, D. A., R. R. Hunter, G. R. Nute, M. A. Mitchell, and P. M. Hocking. 2001. Acute heat stress-induced alterations
23. in blood acid-base status and skeletal muscle membrane integrity in broiler chickens at two ages: Implications for meat quality. Poult. Sci. 80:418 – 425.
24. Settar, P., S. Yalcin, L. Turkmut, S. Ozkan, and A. Cahanar. 1999. Season by genotype interaction related to broiler growth rate and heat tolerance. Poult. Sci. 78:1353 – 1358.
25. Song, D. J., and A. J. King. 2015. Effects of heat stress on broiler meat quality. World’s Poult. Sci. J. 71:701 – 709.
26. Steiner, A. A., and L. G. S. Branco. 2001. Nitric oxide in the regulation of body temperature and fever. J. Therm. Biol. 26:325 – 330.
27. Wideman Jr, R. F., Kirby, Y. K., Ismail, M., Bottje, W. G., Moore, R. W. and Vardeman, R. C. 1995. Supplemental L-arginine attenuates pulmonary hypertension syndrome (ascites) in broilers. Poult. Sci. 74: 323 – 330.
28. Wu, G. 2009. Amino acids: Metabolism, functions, and nutrition. Amino Acids. 37:1 – 17.
29. Yang, L., G. Y. Tan, Y. Q. Fu, J. H. Feng, and M. H Zhang. 2010. Effects of acute heat stress and subsequent stress removal on function of hepatic mitochondrial respiration, ROS production and lipid peroxidation in broiler chickens. Comp. Biochem. Physiol. C. Toxicol. Pharmacol. 151:204 – 208.

Dietary arginine responses of Ross 708 broilers reared under cyclic elevated temperatures yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

The future of gut health lies in combining scientific insight with practical application, ensuring that advances in research translate into real-world improvements in production. Translating experimental findings into the field is vital. One of the most important areas for research is the functional understanding of the gut microbiome. We know which bacteria are there, but we still need to better understand how these communities influence host physiology and performance. Another priority is the development of practical diagnostic tools that can be easily used on farms.

Following the 9th International Conference on Poultry Intestinal Health (ICPIH) in Istanbul, we had the opportunity to exchange views with Professor Filip Van Immerseel of Ghent University, Belgium, who also served as one of the co-chairs of this year’s conference. As one of the leading experts in poultry gut health research, Van Immerseel has played a key role in advancing our understanding of the complex interactions between nutrition, microbiota, immunity, and intestinal function, helping to bridge the gap between fundamental science and practical poultry production.

In this exclusive interview, he reflects on the major themes and scientific developments that shaped ICPIH 2026, from the growing focus on microbiome functionality and organoid research to the industry’s accelerating shift toward preventive gut health strategies. He also shares his perspective on the challenges facing poultry producers in an era of reduced antibiotic use, the evolution of diagnostic technologies, and the role that gut health plays in improving both production efficiency and environmental sustainability. The conversation provides valuable insights into where poultry gut health research stands today—and where it is heading in the years ahead.

Let’s start with the 9^th International Conference on Poultry Intestinal Health (ICPIH), which just wrapped up in Istanbul. Looking at this year’s themes and the profile of attendees, what shifts have you observed in the industry’s focus? And what were your personal “top three” takeaways from the conference?
This year’s conference highlighted that poultry research is moving away from simple studies on single pathogens or processes — what are known as reductionist approaches — towards an integrated, systems-level understanding of gut health. It is well understood that gut health is complex, and that nutrition, microbiota, immunity, and environmental factors interact dynamically within an animal, and methods that capture all of these dimensions should be used. Another important theme was the use of in vitro cell systems to study disease; the organoid research, involving 3D, miniaturized and simplified versions of the gut grown in vitro, was a major innovation for poultry research. Also, it became clear that data collection is no longer limited to performance metrics but includes many indicators of gut functionality, measured by a variety of assays, some of which are increasingly being introduced in industrial settings.

Gut health is not a single-discipline topic and that was reflected in the conference. Data scientists, molecular biologists, and specialists in bioinformatics, alongside traditional nutritionists and veterinarians, were all part of the audience, ensuring multidisciplinary collaborations.

Top 3 takeaways. Number 1. Microbiome research is maturing, from studying single pathogens or bacteria, or generating huge amounts of sequencing data without proper analysis, towards data generation aimed at understanding microbial functions that support gut health. Number 2. Many innovative tools are being developed to support gut health research. Organoids are one of them, but also molecular diagnostic tools are becoming more advanced and in the near future will become more and more accessible. Third, the industry is clearly aligning around prevention to overcome issues related to antimicrobial usage.

Gut health has become a highly debated topic, both in poultry production and more broadly across the livestock industry. Could you explain the reason behind this? When things go wrong in a broiler’s gut, what are the practical implications for the producer?
Gut health problems cause many issues. When gut health is optimal, nutrients are efficiently digested and absorbed, the microbiota is stable, and the immune system remains balanced. So, in case of gut health problems, flocks experience poor feed efficiency, within-flock variability, low performance, so high costs, also related to treatments. Also, animal welfare can be affected, not only by disease, but also poor litter quality leading to dermatitis.

The importance of the gut microbiome was a recurring theme throughout the conference, and it’s also central to your own research. What are the key factors that distinguish a healthy gut microbiome from a diseased one? In other words, what are the biological and physiological parameters of a healthy gut?
A healthy gut microbiome is characterized by a stable and resilient ecosystem that supports digestion, protects against pathogens, and strengthens the intestinal epithelial lining. One of the important aspects of a healthy microbiome is diversity, creating resistance against disturbances such as dietary changes or pathogen exposure. Also, functional activity is equally important, by producing beneficial metabolites such as short-chain fatty acids, playing a crucial role in maintaining intestinal integrity, providing energy to epithelial cells, and modulating the immune response. This results in well-developed villi, strong tight junctions between cells, and a balanced level of immune activity. In contrast, a diseased or dysbiotic microbiome often shows reduced stability and an overrepresentation of opportunistic pathogens such as E. coli and enterococci, supporting inflammation and bacterial translocation.

The threats to gut health in the poultry sector are constantly evolving. Today, especially in a world where antibiotic use is restricted, what are the primary challenges keeping producers up at night (e.g., Necrotic Enteritis, Coccidiosis, etc.)? How should producers manage these threats? Is it truly possible to maintain gut health without the use of antibiotics?
With regard to intestinal health, poultry producers may face many challenges, including indeed diseases, of which coccidia are of major importance, zoonotic infections (Salmonella, Campylobacter) but also conditions that allow opportunistic pathogens to proliferate, that depend on diet quality (also mycotoxins), environmental conditions (e.g., heat stress), and many more. Managing these threats requires a holistic approach. Biosecurity and vaccination remain fundamental, but they must be complemented by optimized nutrition and targeted use of feed additives. Gut health can be maintained without antibiotics, but it is not straightforward. It requires a combination of strategies working together, including improved management practices and a deeper understanding of gut biology. Good strategies in the starting phase of the bird are vital, as was demonstrated at the conference with talks on early nutrition, on-farm hatching, dietary additives early post-hatch and more.

Drawing on the research presented at ICPIH, which innovative solution — whether a new feed additive, a nutritional strategy, or a digital monitoring tool — did you find the most “promising” for supporting gut barrier function or controlling pathogens? Which approaches stood out the most at the conference?
With regard to additives, many are very promising so it is clear that many solutions are being developed. What is more important to me is how we evaluate gut health and in this regard, the development of models (organoid work) and molecular diagnostic tools (also digital tools) were the highlights, as this brings poultry research to a new dimension.

Probiotics, prebiotics, organic acids, phytogenics… With so many options available, how should producers make the right decision? Is the solution simply finding the “right ingredient,” or is it about the interaction between these substances? And how do you see that synergy being better harnessed in the future?
With the wide range of feed additives available, the challenge for producers is not simply selecting a product, but understanding how different solutions fit together. Producers should base their decisions on specific challenges within their operations, rather than following general trends. No product is fit for all problems. In the future, we are likely to see more tailored solutions, potentially supported by data-driven insights and even farm-specific microbiome profiling. Anyhow, producers should also educate themselves and discuss solutions and trends with veterinarians, nutritionists, and additive developers, to try to find the perfect solution for their farm-specific problems.

There’s a lot of talk about shifting from a reactive to a proactive, preventive approach to gut health management. But how much of that shift is actually taking place in the field? How ready are producers for this kind of change?
The transition from reactive to preventive gut health management is clearly underway, but it is progressing at different speeds across the industry. Larger, more integrated operations are generally leading the way, as they have greater access to data, technology, and technical expertise. External pressures are accelerating the shift. Regulatory restrictions on antibiotics, combined with economic pressures to improve efficiency, are making preventive strategies more attractive and, in many cases, necessary. Also, here veterinarians play a key role in supporting preventive approaches, while of course keeping treatment options within reach.

How can the producers in the field monitor gut health? Are there practical and reliable diagnostic tools available? In what direction is research in this field heading?
Monitoring gut health has traditionally been based on post-mortem examinations and performance indicators. While useful, these methods only provide information after problems have already occurred, and post-mortem analysis needs bird euthanasia when used for health monitoring. Often these are still the gold standards. Today, there is a strong movement towards proactive tools, using biomarkers in blood, feces, or even litter, that are gradually becoming available for field use. Sensors and real-time monitoring tools are also a field of growing interest. These topics were highlighted in many talks in the conference. The ultimate goal is to enable producers to make informed decisions in real time, improving both performance and animal welfare.

What role does improving gut health play in reducing the environmental footprint of livestock production (via the feed conversion ratio)? Does a healthy gut ultimately mean a greener industry?
A healthy gut allows birds to extract more nutrients from the same amount of feed, reducing the resources required for production. Improved gut function also reduces nutrient excretion, particularly nitrogen and phosphorus, which are major contributors to environmental pollution. So yes, the environmental footprint is reduced when gut health and performance is optimal. Of course, many other factors also play a role.

Looking ahead, which areas do you believe require a greater focus in terms of both research and commercial applications within the field of gut health?
The future of gut health lies in combining scientific insight with practical application, ensuring that advances in research translate into real-world improvements in production. Translating experimental findings into the field is vital. One of the most important areas for research is the functional understanding of the gut microbiome. We know which bacteria are there, but we still need to better understand how these communities influence host physiology and performance. Another priority is the development of practical diagnostic tools that can be easily used on farms. These tools need to translate complex biological data into simple, actionable insights. At the conference, we could clearly see that a lot of progress has been made.

About Filip Van Immerseel
Filip Van Immerseel received a Master’s degree in Bio-engineering Sciences from the Catholic University of Leuven (KUL) in 1999 and a Master’s degree in Laboratory Animal Sciences from Ghent University in 2004. He earned a PhD in Veterinary Medical Sciences from Ghent University in 2004, focusing on intestinal immune cell infiltration following Salmonella infection in chickens and on environmental triggers in the gut that influence Salmonella invasion.
Following a postdoctoral research period, he was appointed Research Professor at Ghent University in 2008. He is currently Professor at the Department of Pathobiology, Pharmacology and Zoological Medicine within the Faculty of Veterinary Medicine at Ghent University, Belgium, and heads a research group studying host–bacterium interactions.
Filip Van Immerseel has authored more than 240 scientific papers published in international peer-reviewed journals, contributed book chapters, and edited books on Salmonella and Clostridium perfringens. He is a well-known speaker at international scientific and industry events. He serves as Editor of the journal Avian Pathology and is actively involved in numerous international collaborative research networks.
He also holds a dozen patents and is engaged in valorization activities aimed at bringing novel scientific developments to the market.

From microbiome to management: A new era for poultry gut health yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Productivity and sustainability in poultry production are under increasing pressure from mycotoxin contamination in feed, an issue of growing concern across the Middle East and Africa (MEA). Addressing this challenge requires a comprehensive, integrated mitigation strategy.

Mycotoxins, the secondary metabolites produced by filamentous fungi, along with their masked forms, are widely recognized as unavoidable contaminants within food and feed chains (Kovač Tomas & Jurčević Šangut, 2025). The problems can start already in the field and before harvest when cereals and cereal by-products (the main ingredients for poultry diets) become infected with field fungi such as Fusarium spp., favored by moisture during crop development. Additionally, storage fungi like Aspergillus spp. and Penicillium spp. thrive under warm and humid environments during storage and transportation, leading to common mycotoxin accumulation in feed.

THE BIG 6 MYCOTOXIN THREATS FOR POULTRY
While over 400 mycotoxins have been identified, the mycotoxins of greatest concern in poultry production consistently include aflatoxins (AF), deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin, fumonisins (FUM), and ochratoxin A (OTA). These compounds are among the most frequently detected contaminants in animal feed and are widely recognized for their detrimental effects on poultry gut health, organs, immunity, performance, and productivity (Filazi et al., 2017; Jalilzadeh-Amin et al., 2023; Ochieng et al., 2025).

Chronic exposure to these toxins, even at subclinical levels, can cause significant economic losses by reducing feed conversion efficiency, increasing mortality, weakening the immune system, and heightening susceptibility to infectious diseases such as coccidiosis, salmonellosis, and colibacillosis, and negatively affecting reproductive performance in poultry. Additionally, the transfer of toxic residues into meat and eggs poses a serious risk to consumer health, representing a major public health concern, particularly in regions with limited regulatory monitoring (Olariu et al., 2025; Song et al., 2023).

Aflatoxins (AF)
Aflatoxin exposure has been associated with a number of adverse effects in birds, including decreased egg production, organ damage, weaker immunity, and poor performance. Broiler liver and muscle tissues have been found to contain AFB1 residues, with levels of accumulation varying according to exposure time and dosage (Ochieng et al., 2025; Okasha et al., 2024; Olariu et al., 2025).

Deoxynivalenol (DON)
Deoxynivalenol (DON) is widely recognized for its detrimental effects on animal health, well-being and performance. In poultry, DON exposure has been demonstrated to suppress growth and immunological function and contribute to wet droppings. Notably, DON induces intestinal inflammation and disrupts tight‑junction integrity in laying hens, indicating direct impairment of the gut barrier and a potential role in the development of intestinal dysbiosis. Across livestock and experimental models, numerous studies show that DON impairs nutrient absorption and general physiological processes. Intestinal and immunity dysfunction, decreased feed intake, slower growth rates, and lower feed conversion efficiency are all consequences of chronic exposure (Okasha et al., 2024; Olariu et al., 2025; Zhai et al., 2022).

Zearalenone (ZEN)
Broiler chickens exposed to zearalenone (ZEN) show clear performance impairments, including reduced body weight and weight gain, decreased feed intake, and an increased feed conversion ratio (FCR). High dietary levels of ZEN also exert strong estrogenic effects that can lead to hormonal imbalance, reproductive disorders, and, in severe cases, infertility. Additionally, ZEN disrupts endocrine function by binding to estrogen receptors, leading to hormonal dysregulation and impaired reproductive health. (“Mycotoxin Impact on Egg Production,” 2017; Okasha et al., 2024). ZEN and its masked metabolites have been detected in several poultry tissues, including the liver, blood, kidney, muscle, intestine, and in excreta, demonstrating its systemic distribution. Findings from Okasha et al. (2024) further confirm the presence of ZEN residues in broiler liver samples, underscoring the risks associated with contaminated feed.

Fumonisins (FUM)
When exposed to high concentrations of fumonisins, poultry show significant health and performance impairments. Reduced weight gain, poor feed conversion, increased kidney and liver weights, and liver necrosis are among the consequences that have been reported. Because FB1 affects sphingolipid metabolism, it is frequently linked to hepatotoxicity and nephrotoxicity (“Mycotoxin Impact on Egg Production,” 2017; Okasha et al., 2024; Olariu et al., 2025). Clinical signs of fumonisin intoxication in poultry include lameness, leg weakness, wet droppings, decreased egg production, and, in extreme situations, mortality. There have also been reports of immunological disorders, including lymphocyte suppression, decreased humoral immunity, and immunosuppression. Furthermore, birds exposed to fumonisins often exhibit intestinal and hepatic congestion, as well as an increased risk of coccidiosis and necrotic enteritis (Júnior et al., 2022).

Ochratoxin A (OTA)
Poultry’s gastrointestinal tract (GIT) is significantly affected by ochratoxin A (OTA), which compromises the mucosal barrier through damage to intestinal epithelial cells, alterations in gut microbiota composition, and downregulation of tight junction proteins. These disruptions collectively impair nutrient absorption and consequently lead to reductions in body weight and weight gain. Beyond its intestinal effects, OTA poses major risks due to its nephrotoxic, hepatotoxic, and immunosuppressive properties, making it one of the most harmful mycotoxins encountered in poultry production (Bonerba et al., 2024; Okasha et al., 2024; Olariu et al., 2025; S. Zhai et al., 2021).

T-2 toxin (T-2)
T-2 toxin exert a wide range of toxic effects in poultry. These include inhibition of protein, DNA, and RNA synthesis, leading to pronounced cytotoxicity, compromised immunological responses, and greater susceptibility to infectious diseases in poultry. In addition to neurological disorders and general declines in performance, such as decreased weight gain, decreased egg production, and decreased hatchability, affected birds frequently develop oral lesions as well as others in the digestive tract, liver, kidneys, skin, and other rapidly dividing tissues (Olariu et al., 2025; Vörösházi et al., 2024).

The global significance of the six major mycotoxins stems from their high prevalence, with estimates suggesting that more than 60% of feed commodities worldwide are contaminated, making mycotoxins among the most widespread natural toxins affecting animal health and nutrition (Hassan et al., 2026).

CHALLENGING CONDITIONS IN MEA REGION
In the Middle East and Africa (MEA) region, mycotoxin contamination in animal feed is strongly influenced by a combination of climate change, agricultural practices, economic factors, and feed processing methods. Mycotoxin accumulation due to warm and humid conditions is especially challenging within MEA supply chains (Gomes et al., 2025; Kovač Tomas & Jurčević Šangut, 2025). In addition, many countries in the MEA region depend heavily on imported feed ingredients, where contamination can occur prior to importation, during transportation, or throughout storage. Inadequate storage conditions, warm climates, and lengthy supply chains further increase the risk, making effective mycotoxin management a persistent challenge (Jalilzadeh-Amin et al., 2023).

Furthermore, the co-occurrence of various mycotoxins in feed raw materials and finished feeds is commonly observed worldwide as individual fungi species may produce more than one mycotoxin, and several mycotoxins can also be synthesized by different fungi (Gomes et al., 2025). In addition, masked (hidden) mycotoxins and their metabolites may escape conventional detection yet be converted back into their toxic forms during digestion, further complicating risk assessment (Okasha et al., 2024). As a result, animal feeds often contain several mycotoxins simultaneously, creating complex interactions. Even when present at individually subclinical concentrations, these compounds may exert antagonistic, additive, or synergistic effects, thereby increasing their overall toxic impact. During challenging conditions, involving disease pressure or heat stress, feed that is contaminated with multi-mycotoxins can further spiral down bird health and performance.

ANALYSIS OF RAW MATERIALS IN LEBANON
Mycotoxin co-occurrence in animal feed is a prominent phenomenon, with interactions between toxins frequently resulting in additive or synergistic effects that increase their impact on animal health. According to previous studies, 30% to 100% of feed samples contained two or more mycotoxins (Jalilzadeh-Amin et al., 2023). The current monitoring of raw feed ingredients (corn and soybean meal) in Lebanon, based on an assessment conducted by UTRIX S.A.L. (hereafter called ‘UTRIX’), confirmed the widespread nature of co-contamination under local conditions by showing that 100% of examined samples were contaminated with at least two or more mycotoxins.

Using ELISA-based analysis, UTRIX conducted a three-year assessment (2023-2025) and found a consistent pattern of multi-mycotoxin contamination with significant temporal fluctuations (Figure 1). Zearalenone (ZEN) showed elevated levels in 2023 and 2025, while fumonisins (FUM) were the most common toxins in all years, with a notable increase in 2025. These results are consistent with research showing that FUM and ZEN are present in both summer and winter, demonstrating how toxicogenic fungi may adapt to different environmental conditions (Gomes et al., 2025). In Lebanon, where warm summers and mild, wet winters promote year-round fungal growth, this seasonal persistence is very significant and could account for the recurring prevalence of FUM and ZEN. In contrast, DON showed a declining trend, whereas AF increased over time, and surpassed locally applied thresholds in 2025. OTA remained consistently low, and T-2 toxin showed a gradual increase, indicating a potential emerging risk.

The 2025 results show exceedances for ZEN, FUM, and AF when compared to advisory threshold levels. The mycotoxins’ co-occurrence in this study highlights the importance of considering combined toxicological effects, while their seasonal persistence emphasizes the necessity for ongoing monitoring and integrated mitigation efforts in Mediterranean-like climates.

MULTI-LEVEL MYCOTOXIN CONTROL STRATEGIES
Various strategies are used to reduce mycotoxin contamination in feed, including proper post-harvest practices, strict quality control during sourcing and storage, and physical methods such as sorting and cleaning (Okasha et al., 2024).

Feed additives, particularly anti-mycotoxin solutions, play a central role by reducing toxin bioavailability. Compounds such as modified clays, yeast cell wall extracts, and enzymes can adsorb or biotransform a wide range of mycotoxins, including masked forms, thereby limiting their absorption in the GIT (Kolawole et al., 2025). Overall, effective management requires an integrated approach combining prevention, monitoring, and targeted mitigation strategies.

In line with these mitigation strategies, UTRIX offers a range of mycotoxin management solutions, including UtriSorb^®, UtriSorb^®PRO, KleenTox^®PLUS, KleenTox^®PRO, KleenTox^®ADVANCE, and KleenTox^®DW. Among these, KleenTox^®PRO is a broad-spectrum mycotoxin binder combining attapulgite clay, yeast cell wall extract, enzymes, and plant extracts, enabling simultaneous adsorption and biotransformation of multiple mycotoxins while supporting the immune system, liver function, and gut health. This multi-component approach enhances protection against complex mycotoxin challenges commonly observed under field conditions.

Additionally, KleenTox^®DW, a mycotoxin control solution for application in drinking water, provides a complementary strategy by delivering rapid and effective mycotoxin control through a synergistic blend of organic acids, yeast cell wall extract, and cinnamaldehyde, thereby supporting gut integrity and immune function. To address fungal proliferation at the source, UTRIX offers MoldBan^®, a mold inhibitor applied in feed that limits fungal growth and spoilage through organic acid-based antifungal activity. This helps preserve raw material quality, extend shelf life, and reduce the risk of mycotoxin production.

CONCLUSION
While mycotoxin threshold levels are designed to ensure feed safety, increasing evidence indicates that chronic exposure to low concentrations of multiple mycotoxins, even within accepted limits, can negatively impact animal performance. These subclinical effects often go unnoticed yet are associated with reduced feed efficiency and productivity losses across livestock systems (Kolawole et al., 2025).

Mycotoxin contamination arises from the proliferation of toxigenic fungi, including Aspergillus, Fusarium, and Penicillium, on feed ingredients. This contamination can occur both before and after harvest under favorable conditions such as high moisture levels, inadequate storage, and poor handling practices (Okasha et al., 2024). Given the strong influence of environmental and biological factors on fungal growth, understanding regional contamination patterns is crucial for accurate risk assessment and the development of effective control strategies (Kovač Tomas & Jurčević Šangut, 2025). It also emphasizes the necessity for ongoing monitoring and integrated mitigation efforts in Mediterranean-like climates.

Therefore, safeguarding animal health, performance, and productivity requires an integrated approach combining improved feed management, targeted mitigation strategies, and coordinated efforts among industry stakeholders to enhance monitoring and control systems.

References are available on request.

About Rola Jreissaty
Rola Jreissaty is a Product Manager at UTRIX S.A.L., a premier producer of premixes, concentrates, and feed additives and specialties. Jreissaty oversees the development and marketing of UTRIX’s anti-mycotoxin portfolio, as well as other product categories.

Mycotoxin challenges in mea requires integrated mitigation approach yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Mycotoxin contamination in poultry feed is a persistent challenge in commercial production worldwide. Among the various mycotoxin groups, Fusarium toxins have gained increasing attention over the past decades, not only due to their widespread presence in commonly used grains but also because of their capacity to interact with and amplify the effects of other toxins. Understanding which Fusarium toxins are truly relevant in poultry, how to identify them, and how to select and evaluate effective control strategies is essential for any poultry health professional. This article provides a practical overview of the main Fusarium toxins affecting commercial poultry, the tools available for their detection, and the criteria for choosing and validating anti-mycotoxin additives.

The Fusarium mycotoxins group includes Zearalenone (ZEA) and Fumonisin (FUM). For decades, both toxins were irrelevant, to a certain extent, in commercial poultry, but are now constantly evaluated in feed analyses and considered important mycotoxins affecting performance. In the case of ZEA, despite being frequently present in grains and used as a marker for other mycotoxins, scientific and field reports indicate that it is not very toxic in either broiler chickens or hens. The situation with FUM is different because most of the corn produced globally shows its presence. In corn harvested in the United States, Argentina, and Brazil, it is common to detect levels of 1,500 to 4,000 ppb of FUM. As a result, many clinicians are diagnosing mycotoxicosis caused by FUM in cases where the etiologic agent is completely different. Inclusion Body Hepatitis (IBH), for example, is frequently misdiagnosed as mycotoxicosis.

Inside the Fusarium toxins, there is another classification called Trichothecenes, characterized by a similar chemical structure, which represents another important group affecting performance and causing specific gross lesions. T-2 toxin, DAS (diacetoxyscirpenol), and Vomitoxin/DON are the most relevant. The oral lesions caused by T-2 toxin and DAS are easily identified as a sign of mycotoxicosis in poultry farms. In the case of DON, identifying typical gross lesions is more difficult, though several scientific papers report microscopic damage to the intestinal integrity. Something widely accepted by the scientific community is that the presence of Fusarium toxins significantly potentiates the damage caused by mycotoxins traditionally recognized as more toxic, such as Aflatoxin, Ochratoxin, and T-2 toxin.

DETERMINING WHICH MYCOTOXINS CAUSE DAMAGE IN POULTRY PRODUCTION
Determining which mycotoxins cause damage is ideally one of the first steps to consider before choosing an anti-mycotoxin additive. Identifying characteristic lesions facilitates this task, since most mycotoxins affect specific target organs. For example, T-2 toxin, HT-2, or DAS can produce mouth ulcers, unlike Aflatoxin, which affects the liver and/or causes bruises in the skin and muscles. Under commercial conditions, most companies decide which product to include after evaluating feed mill analyses and, in some cases, reports of negative effects on performance. For farms that can identify which mycotoxins are affecting their flock through macroscopic or histopathological evaluations, this information allows them to select products with proven efficacy against the specific toxins present. Since more than one mycotoxin is generally present in the ration, combining two types of mycotoxin binders is sometimes necessary to achieve a broader spectrum of protection.

Although testing for mycotoxins in feed is a very practical way of finding out which ones are present, there are certain limitations to this tool. Results can vary due to the uneven distribution of mycotoxins in the samples analyzed, regardless of the laboratory technique used, whether simple tests such as ELISA (well known for its limited sensitivity) or more sophisticated methods such as HPLC (high-performance liquid chromatography) or LC-MS/MS (Liquid Chromatography-Tandem Mass Spectrometry).

ANTI-MYCOTOXIN SOLUTIONS
Over the years, various anti-mycotoxin feed additives have been developed, including the following:
Traditional clays represent the first generation of products developed for aflatoxin control. Some clays can adsorb other mycotoxins in addition to aflatoxin, but their spectrum of action is not as broad as that of purified clays.

Purified clays are modified and activated through specialized processes—many are identified as organo-clays. Within this group, some have demonstrated efficacy in experimental trials against difficult-to-capture mycotoxins such as ZEA, as well as T-2 toxin and FUM.

Products containing bacteria, yeast cell walls, enzymes, and/or algae are frequently combined with clays. Some manufacturers claim that the microorganisms present can metabolize mycotoxins and convert them into less toxic metabolites.

HOW TO EVALUATE MYCOTOXIN BINDERS?
Considering the large number of products available in the global market, the following are key factors to consider before deciding which additive to use.

1. In vitro test
A preliminary test and essentially a quality control measure. If a product works in vitro, it does not mean that it works in vivo. The test consists of determining the adsorption capacity of a product against different mycotoxins using HPLC at two pH levels (3.0 and 6.0), simulating the conditions of the gastrointestinal tract. Under no circumstances should the decision on which product to use be based solely on in vitro testing, it must always be accompanied by animal testing. The inclusion rate recommended in the feed should be the same as that used in this test.

2. In vivo test
When conducting this type of test, it is necessary to measure performance (body weight gain, feed intake, feed conversion, and target organ protection). For example, if the efficacy of a product against aflatoxin is being measured, its effect on the liver must be quantified. If a product is evaluated against T-2 toxin, the effect of the anti-mycotoxin additive on oral lesions must be assessed. Although T-2 toxin causes damage through direct contact due to its causticity when ingested, an effective additive will reduce the degree of oral lesions through its adsorption capacity in the intestines. Some mycotoxins, such as FUM, do not cause macroscopic damage to the chicken liver, so it is necessary to measure biomarkers such as sphingosine and sphinganine, which are produced by the toxic effect of FUM on sphingolipid metabolism in blood. The dose recommended under commercial conditions should be the same as, or close to, the one tested in vivo. When evaluating additives containing substances that act as growth promoters (yeasts, enzymes, immune stimulants), their effectiveness should not be based solely on favorable performance results.

3. Detection of markers/metabolites in blood
Metabolites of emerging mycotoxins such as Beauvericin, and other toxins such as Tenuazonic acid, are measured in blood and reported to poultry growers as indicators of mycotoxin exposure. Based on the scientific literature reviewed, the importance of these newer mycotoxins has not yet been established in commercial poultry production. For commercial farms fed with DON-contaminated feed, metabolites such as Deoxynivalenol-3-sulphate have been measured before and after using a mycotoxin binder.

4. Identification of lesions at the slaughterhouses
This tool demonstrates whether an anti-mycotoxin additive is working properly once it has been included in the diet. Every week, examine at least 200 to 300 birds at the slaughterhouse, looking for mycotoxin-associated lesions in the carcasses. To further support this evaluation, it is ideal to periodically submit formalin-fixed tissue samples for histopathological assessment.

CONCLUSION
It is critical to determine what type of mycotoxins are affecting the birds in order to decide which binder to include in the feed. Once an anti-mycotoxin additive has been selected, slaughterhouse evaluations will supply critical information regarding the efficacy of the product chosen.

Mycotoxins control in poultry: Fusarium toxins yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Supporting poultry during heat stress requires a multi-faceted strategy addressing both environmental and nutritional factors. When high temperatures and humidity exceed birds’ tolerance, their behaviour, feed intake, and calcium metabolism are disrupted. This leads to issues like poor shell quality and reduced egg production. Practical management and precise diet formulation are key—but how can these be optimised to limit productivity losses?

By Phosphea
Heat stress can represent a pressing concern during the summer season. With temperatures frequently above 30 degrees surpassing the 25 degrees comfort range for a poultry, the physiological challenges become more pronounced.

WHAT IS HEAT STRESS IN POULTRY?
Heat stress in poultry refers to a condition where they are exposed to high temperatures and humidity levels that exceed their physiological tolerance. It occurs when the bird is unable to dissipate the heat leading to various changes in the behavior of the poultry. The impact on productivity is high, this is why preventing it, is mandatory.

To evaluate the level of heat stress, the Temperature Humidity Index (THI) is commonly used. It is a numerical value to measure the combined effect of temperature and humidity on the thermal comfort and stress levels of poultry. A higher THI value indicates a greater risk of heat stress (Habeeb, 2018).

For example, a temperature of 28°C with a Humidity Level of 95 % has the same THI level as a temperature of 38 degrees with a 20% humidity.

WHAT ARE THE CONSEQUENCES OF HEAT STRESS IN POULTRY?
The bird resort to panting in order to dissipate heat from their body, by opening their mouth, their feathers and wings, often leading to a decrease in feed intake and nutrient absorption. This hyperventilation leads to low CO₂ levels in blood and an increase of the blood pH. To compensate it, the bird degrades part of the bones to obtain carbonates and restore the blood levels. This process can lead to decrease in calcium storage of medullary bone, essential to eggshell formation (30 to 40%) during laying period. Consequently, we can observe declines in egg size, shell quality, shell color and broken eggs more frequent (Soriano, 2021).

HOW CAN WE SUPPORT ANIMALS DURING HEAT STRESS?
The strategy to avoid maximum issues caused by heat stress should be a combination of:
• Management measures: Proper density and lighting, implementation of ventilation systems and roofing sprinklers, monitorization of feed and water intake and control of the water supply and its temperature.
• Formulation assessment: Good balance and digestibility of the diet, calcium incorporation rate and form. For example, the addition of fat instead of carbohydrates in the formulation may reduce the production of heat and increase palatability.
• Time adjustment: Feeding at the cooler time of the day is ideal to optimize the feed intake. Manipulation of the poultries should also be during those hours.

These security and prevention measures are the first steps to reduce the impact of the heat stress (Wasti, 2020).

HOW CAN CALSEAGROW HELP POULTRY UNDER HEAT STRESS?
To mitigate heat stress, Phosphea created a unique blend of Peptic-oligosaccharides prebiotics and antioxidants specifically designed for layers and breeders. Due to its specific synergy between marine calcium and citrus extract, CalseaGrow provides prebiotic (POS) and antioxidant properties to the bird leading to better calcium mobilization for the bones and eggshell and control of oxidative stress caused by Heat Stress. By incorporating CalseaGrow at 1kg/ton of feed into their diet it is possible to enhance calcium deposition in both bones and eggshell increasing the shell quality of the egg.

Additionally, this innovative approach reduces the oxidative stress, improves feed intake during stress by increasing the nutrient absorption. It maintains and promotes gut health, which contribute to sustain egg production.

Our recommendation is: Supplement CalseaGrow 2 weeks before the heat wave, in order to help counteract the negative effects of heat stress.

Supporting poultry during heat stress: Risks and technical solutions yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Heat stress in poultry production is a common reality; its effects are quite complex and harmful and depend on the intensity and duration of the exposure to high temperatures. The gut is affected by heat stress through several pathways, including organ ischemia and hypoxia, as well as oxidative stress. In heat stress challenges, the intestinal barrier is compromised because of lower tight junction protein expression, enterocyte damage, and microbiome unbalance, leading to gut health issues such as dysbiosis and necrotic enteritis.

By the Technical Team of EW Nutrition
Stress in animals can be defined as any factor causing disruptions to their homeostasis, their stable internal balance. Stress engenders a biological response to regain equilibrium.¹ We can distinguish four major types of stress in the poultry industry: Technological or management-related stress; environmental stress; nutritional stress, including due to heavy metals, mycotoxins, and low-quality ingredients; and internal stress, which is related to health status and health challenges.² All types of stress lead to molecular and cellular changes that decrease health and productivity.

CLIMATE CHANGE, THERMOREGULATION, AND STRESS
High environmental temperatures are among the most important environmental stressors for poultry production, causing significant economic losses in the industry.³ Climate change has increased the prevalence and intensity of heat stress conditions in most poultry production areas all over the world.^4,5

The optimum temperature for poultry animals’ well-being and performance – the so-called thermoneutral zone – is between 18 and 22°C. When birds are kept within this temperature range, they do not have to spend energy on maintaining a constant body temperature.⁶

Heat stress is the result of unsuccessful thermoregulation in the animals, as they absorb or produce a higher quantity of heat than they can lose. It means that there is a negative balance between the net amount of energy flowing from the animal to the environment and the energy it produces.⁷

CONTRIBUTING FACTORS TO HEAT STRESS IN POULTRY
This energy imbalance is influenced by environmental factors such as sunlight, thermal irradiation, air temperature, humidity, and stocking density, but also by animal-related factors such as body weight, feather coverage and distribution, dehydration status, metabolic rate, and thermoregulatory mechanisms.^7,8 When the environmental temperature is above the thermoneutral zone, the animals activate thermoregulation mechanisms to loose heat through behavioral, biochemical, and physiological changes and responses.^9-12

Heat stress can be classified into two main categories: Acute and chronic. Acute heat stress refers to a short and fast increase in environmental temperature (a few hours), whereas under chronic heat stress the high temperatures persist for more extended periods (several days). Some studies suggest that, in some circumstances, poultry animals show a degree of resilience to acute heat stress.^7,9,10 However, in the long-run, their compensatory mechanisms are not sufficient to maintain tissue integrity and thus health and performance.¹¹

THE ANIMAL’S RESPONSE TO HEAT STRESS
The exposure of poultry to heat stress changes the gene expression of cytokines, upregulates heat shock proteins (HSP), and reduces the concentration of thyroid hormones.^10,12 When heat stress persists, these cascades of cellular reactions result in tissue damage and malfunction.

The animals exposed to heat stress suffer adverse effects in terms of performance, which are widely known and include high mortality, lower growth and production (Figure 1), and a decline in meat and egg quality.^13,14

OXIDATIVE STRESS – A CONSEQUENCE OF HEAT STRESS
Oxidative stress, simply put, occurs when the amount of reactive oxygen species (ROS – such as superoxide anions, hydrogen peroxide, and hydroxyl radicals) exceeds the antioxidant capacity of the cells.^6,14,15 Oxidative stress is regarded as one of the most critical stressors in poultry production as it is a response to diverse challenges affecting the animals.^2,17

At a cellular level, the metabolism of the animal – its energy production – generates ROS and reactive nitrogen species (RNS), such as hydroxyl radicals, superoxide anions, hydrogen peroxide, and nitric oxide. These usually are further processed by antioxidant enzymes produced by the cell^2,15, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Nutrients such as selenium and vitamins E, C, and A also participate in antioxidant processes.^2,5 When the generation of ROS exceeds the capacity of the antioxidant system, oxidative stress ensues.^2,16

Heat stress in poultry leads to higher cellular energy demand, promoting the generation of ROS in the mitochondria¹³, which exceed the antioxidant capacity of the organism. As a consequence, oxidative stress occurs in several tissues, leading to cell apoptosis or necrosis.¹¹ Among these tissues, the gastrointestinal tract can be highly affected.

Oxidative stress damages cell proteins, lipids, and DNA, and reduces energy generation efficacy.6 Moreover, oxidized molecules can take electrons from other molecules, resulting in a chain reaction. If not controlled, this reaction can cause extensive tissue damage.¹⁶

In response to oxidative stress, all antioxidants in the organism work together to re-establish homeostasis. Several steps in the oxidative stress response have been identified. Whether they take place depends on the intensity of the stressor, with ROS and RNS acting as signalling molecules. These steps include the internal synthesis of antioxidants, the activation of transcription factors or vitagenes, and the production of protective molecules (Figure 2).

OXIDATIVE STRESS’ EFFECTS ON THE GUT
In the gastrointestinal tract, oxidative stress and the consequent tissue damage lead to increased intestinal permeability. This facilitates the translocation of toxins and pathogens from the intestinal tract into the bloodstream (Figure 3).

Under oxidative stress conditions in the gut, there is a demand for antioxidants to counteract the excess of ROS; hence, dietary antioxidants can help reduce ROS and improve animal performance.¹⁵ Research shows that certain phytomolecules have antioxidant properties and improve performance under conditions of oxidative stress.^14,18-20

Thermoregulation: Changes in blood flow
The gastrointestinal tract is profoundly affected by heat stress in poultry: to help with heat dissipation, the thermoregulatory mechanism of the animal shifts visceral blood flow towards peripheral circulation. Organ ischemia and hypoxia follow, limiting gut motility, nutrient utilization, and feed intake.^5,14 Enterocytes are particularly sensitive to hypoxia and nutrient restriction, which leads to oxidative stress.^2,12

Changes in intestinal barrier’s tight junctions
Several studies indicate that both acute and chronic heat stress increase gut permeability, partly by increasing oxidative stress and by disrupting the expression of tight junction proteins.^5,21 Heat and oxidative stress in the gut result in intestinal cell injury and apoptosis. When the tight junction barrier is compromised, luminal substances leak into the bloodstream, which constitutes the condition described as “leaky gut”.^4,21

Changes in intestinal morphology
Heat stress in poultry affects intestinal weight, length, barrier function, and microbiota, resulting in animals that have lower total and relative weight of the small intestine, with shorter jejunum and duodenum, shorter villi (Figure 4), and reduced absorption areas, in comparison to non-stressed animals.^11,12,23-26

Changes in intestinal microbiome
Due to reduced feed intake and impaired intestinal function, the presence and activity of the commensal microbiota can also be modified. Heat stress can lead to reduced populations of beneficial microbes. At the same time, it can boost the growth of potential pathogens and lead to dysbiosis, increased gut permeability, as well as immune and metabolic dysfunction.²⁷ Burkholder et al. (2008) and Rostagno (2020) point out that pathogens such as Clostridia, Salmonella, and coliform bacteria increase in poultry exposed to heat stress, while the populations of beneficial bacteria such as Lactobacilli and Bifidobacteria decrease.

Necrotic enteritis
Heat stress in poultry causes damage in the gut microbiota, intestinal integrity, and villus morphology, as well as immunosuppression. Consequently, feed digestion and absorption decline.^11,12,28,29 These factors increase the risk of necrotic enteritis outbreaks^5,28,30,31, one of the most problematic bacterial diseases in modern poultry production.

In a study by Tsiouris et al. (2018), cyclical acute heat stress was found to increase the incidence and severity of necrotic enteritis in broilers challenged with C. perfringens, and to produce the disease in animals that were not exposed to the bacteria. Other signs, such as growth retardation and a reduced pH of the intestinal digesta, were also observed in the heat-stressed birds.

By lowering feed digestibility, increasing gut permeability, and compromising immunity, heat stress leaves animals more susceptible to gut-health related issues such as dysbacteriosis and necrotic enteritis – and thus increases the need to use antibiotics.

MITIGATION STRATEGIES
Most intervention strategies deal with heat stress through a wide range of measures, including environmental management, housing design, ventilation, sprinkling, and shading, amongst others.⁸ Understanding and controlling environmental conditions is always a part of heat stress management: it is crucial for ensuring animal welfare and achieving successful poultry production.

Feed management and nutrition interventions are also recommended, together with environmental management, to reduce the effects of heat stress in poultry. They include feeding pelletized diets with increased energy, higher fat inclusions, reduction of total protein, supplemental amino acids, higher levels of vitamins and minerals, and adjusting the dietary electrolyte balance.^1,12,18 Nutrition is crucial, and the use of the right diets aid in attenuating heat stress in birds.

Phytomolecules: Powerful antioxidants
It is practically impossible to avoid stress in commercial poultry production; hence it is common for animals to experience oxidative stress at times. Phytomolecules are natural antioxidants with anti-inflammatory and digestive properties^8,14, which have been shown to improve poultry performance, including during challenging periods. The antioxidant capacity of phytomolecules manifests itself in free radical scavenging, increased production of natural antioxidants, and the activation of transcription factors.^2,32,33

As compounds that have low bioavailability, they can remain at high concentrations within the intestine, when provided at the appropriate dosage and through encapsulation technology. Research has found that phytomolecules can effectively reduce intestinal ROS and thus alleviate heat stress in poultry^15,18-20, specifically mitigating oxidative stress in the intestine.

One heat stress study, for example, found that carvacrol elevates serum GSH-PX activity, compared to non-supplemented broilers.¹⁹ Other studies demonstrate that cinnamaldehyde also increases the activities of natural antioxidants in heat-stressed broilers.^32,35 A study by Prieto and Campo (2016) showed that dietary supplementation of capsaicin effectively alleviated heat stress, as indicated by a lower H/L ratio in supplemented animals.

Silibinin, a flavonolignan present in silymarin (milk thistle extract), is another powerful antioxidant. In the gastrointestinal tract, it can come into direct contact with cells, activating transcription factors such as Nrf2, and thus helping to upregulate the antioxidant protection.³⁴ Other phytomolecules, such as menthol and cineol, also aid animals under heat stress by simulating the sensory cold receptors of the oral mucosa. This gives them a cooling sensation and reduces heat stress behavior.¹⁸

References
¹ Das, S. et al., 2011. Nutrition in relation to diseases and heat stress in poultry. Veterinary World, 4(9), pp. 429-432.
² Surai, P. F., Kochish, I. I., Fisinin, V. I. & Kidd, M. T., 2019. Antioxidant defence systems and oxidative stress in poultry biology: An update. Antioxidants, 8(7).
³ St-Pierre, N., Cobanov, B. & Schnitkey, G., 2003. Economic Losses from Heat Stress by US Livestock Industries. Journal of Daairy Science, Volume 86
⁴ Tellez Jr., G., Tellez-Isaias, G. & Dridi, S., 2017. Heat stres and gut health in broilers: role of tight junction proteins. Advances in Food Technology and Nutritional Sciences, 3(1).
⁵ Lian, P. et al., 2020. Beyond heat stress: intestinal integrity disruption and mechanism-based intervention strategies. Nutrients, Volume 12.
⁶ Akbarian, A. et al., 2016. Association between heat stress and oxidative stress in poultry; mitochondrial dysfunction and dietary interventions with phytochemicals. Journal of Animal Science and Biotechnology, 7(37).
⁷ Lara, L. & Rostagno, M., 2013. Impact of heat stress on poultry production. Animals, Volume 3, pp. 356-369.
⁸ Saeed, M. et al., 2019. Heat stress management in poultry farms: a comprehensive overview. Journal of Thermal Biology, Volume 84, pp. 414-425.
⁹ Farag, M. & Alagawany, M., 2018. Phyisiological alterations of poultry to the high enviromental temperature. Journal of Thermal Biology, Volume 76, pp. 101-106.
¹⁰ Quinteiro-Filho, W. et al., 2010. Heat stress impairs performance parameters, induces intestinal injury, and decreases macrohage activity in broiler chickens. Poultry Science, Volume 89, p. 1905–1914.
¹¹ Santos, R. et al., 2015. Quantitative histo-morphometric analysis of heat-stress-related damage in the small intestines of broiler chickens. Avian Pathology, 44(1), pp. 19-22.
¹² Awad, E. et al., 2018. Growth performance, duodenal morphology and the caecal microbial population in female broiler chickens fed glycine-fortified low protein diets under heat stress conditions. British Poultry Science, 59(3), pp. 340-348.
¹³ Mujahid, A., Yoshiki, Y., Akiba, Y. & Toyomizu, M., 2005. Superoxide radical production in chicken skeletal muscle induced by heat stress. Volume 84, pp. 307-314.
¹⁴ Hu, R. et al., 2019. Polyphenols as potential attenuators of heat stress in poultry production. Antioxidants, 8(67).
¹⁵ Salami, S. et al., 2015. Efficacy of dietary antioxidants on broiler oxidative stress, performance and meat quality: science and market. Avian Biology Research, 8(2), pp. 65-78.
¹⁶ Lauridsen, C., 2019. From oxidative stress to inflammation: redox balance and immune system. Poultry Science, Volume 98, pp. 4240-4246.
¹⁷ Surai, P. F. & Fisinin, V. I., 2016. Vitagenes in poultry production: Part 1. Technological and enviromental stresses. World’s Poultry Science Journal, Volume 72.
¹⁸ Arab Ameri, S., Samadi, F., Dastar, B. & Zarehdaran, S., 2016. Efficiency of peppermint (Mentha piperita) powder on performance, body temperature and carcass characteristics of broiler chickens in heat stress condition. Iranian Journal of Applied Animal Science, 6(4), pp. 943-950.
¹⁹ Saadat Shad, H., Mazhari, M., Esmaeilipour, O. & Khosravinia, H., 2016. Effects of thymol and carvacrol on productive performance, antioxidant enzyme activity and certain blood metabolites in heat stressed broilers. Iranian Journal of Applied Animal Science, 6(1), pp. 195-202.
²⁰ Mishra, B. & Jha, R., 2019. Oxidative stress in the poultry gut: potential challenge and interventions. Frontiers in Veterinary Science, 6(60).
²¹ Ruff, J. et al., 2020. Research Note: Evaluation of a heat stress model to induce gastrointestinal leakage in broiler chickens. Poultry Science, Volume 99, pp. 1687-1692.
²² Rostagno, M., 2020. Effects of heat stress on the gut health of poultry. Journal of Animal Science, 98(4).
²³ Abdelqader, A. & Al-Fataftah, A., 2016. Effect of dietary butyric acid on performance, intestinal morphology, microflora composition and intestinal recovery of heat-stressed broilers. Livestock Science, Volume 183.
²⁴ Jahejo, A. et al., 2016. Effect of heat stress and ascorbic acid on gut morphology of broiler chicken. Sindh University Research Journal, 48(4), pp. 829-832.
²⁵ Wu, Q. et al., 2018. Glutamine alleviates heat stress-induced impairment of intestinal morphology, intestinal inflammatory response, and barrier integrity in broilers. Poultry Science, Volume 97, pp. 2675-2683.
²⁶ Santos, R. et al., 2019. Effects of a feed additive blend on broilers challenged with heat stress. Avian Pathology, 48(6), pp. 582-601.
²⁷ Shi, D. et al., 2019. Impact of gut microbiota structure in heat-stressed broilers. Poultry Science, Volume 98, pp. 2405-2413.
²⁸ Burkholder, K. et al., 2008. Influence of stressors on normal intestinal microbiota, intestinal morphology, and susceptibility to Salmonella Enteritidis colonization in broilers. Poultry Science, Volume 87, pp. 1734-1741.
²⁹ Quinteiro-Filho, W. et al., 2012. Acute heat stress impairs performance parameters and induces mild intestinal enteritis in broiler chickens: role of acute HPA axis activation. Journal of Animal Science.
³⁰ Antonissen, G. et al., 2014. The Impact of Fusarium Mycotoxins on Human and Animal Host Susceptibility to Infectious Diseases. Toxins, 6(2).
³¹ Tsiouris, V. et al., 2018. Heat stress as predisposing factor for necrotic enteritis in broiler chicks. Avian Pathology, 47(6), pp. 616-624.
³² Abd El-Hack, M. et al., 2019. Herbs as thermoregulatory agents in poultry: An overview. Science of the Total Environment.
³³ Surai, P. F., 2020. Antioxidants in poultry nutrition and reproduction: An update. Antioxidants, 9(2).
³⁴ Surai, P. F., 2015. Silymarin as a natural antioxidant: An overview of the current evidence and perspectives. Antioxidants, 4(1).
³⁵ El-Maaty, A., Hayam, M., Rabie, M. & El-Khateeb, A., 2014. Response of heat-stressed broiler chicks to dietary supplementation with some commercial herbs. Asian Journal of Animal and Veterinary Advances, 9(12), pp. 743-755.
³⁶ Prieto, M. & Campo, J., 2010. Effect of heat and several additives related to stress levels on fluctuating asymmetry, heterophil:lymphocyte ratio, and tonic immobility duration in White Leghorn chicks. Poultry Science, Volume 89, p. 2071–2077.

Managing heat stress in poultry: The role of oxidative stress and gut health yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

L-Arginine is a basic amino acid and serves as the most abundant nitrogen carrier in tissue proteins. In mammals, it is considered a conditionally essential amino acid. However, poultry are unable to synthesize arginine on their own, making it an essential amino acid that must be supplied through the diet. The dietary requirement for arginine in broilers varies with the season. During the summer, the requirement increases to support optimal growth under heat stress conditions, so higher levels of arginine should be included in the diet.

ARGININE IS AN ESSENTIAL AMINO ACID FOR BROILERS
Uric acid is the vehicle for nitrogen excretion in poultry metabolism. It originates from the purines which derive their nitrogen from amino acids. Therefore, arginine would not be expected to function in nitrogen transfer to the extent that it does in animals with an ornithine cycle (Figure 1). Klose (1938) and Leveille (1959) studied that arginine is essential for the growing chick as well as the adult bird. Arginine could not be replaced by ornithine and citrulline. Tamir and Ratner (1963) found that carbamyl phosphate synthetase has not been detected in any tissue, while ornithine transcarbamylase, argininosuccinate synthetase, and argininosuccinase lyase have been found in the kidney but not in the liver. Small amounts of argininosuccinate lyase activity were also presented in the spleen, pancreas, and intestinal tract. Jones et al. (1961) studied the enzymes of arginine metabolism in rats. Compared to the enzymes in rats, it can be concluded that arginine is essential for broilers because they lack carbamyl phosphate synthetase.

NUTRITIONAL EFFECT OF ARGININE IN BROILERS
The Requirements of Arginine in Broilers
Arginine is an essential amino acid for broilers. The requirement of arginine in broilers is affected by many factors such as breed, environment, etc. Moreover, Corzo (2020) indicated that the ratio of dArg/dLys increased as the birds’ age increased. The optimum dArg/dLys value to optimize BW gain and FCR from 1-14d was 106 for both parameters, however, it was determined to be 129 and 116 from 25 – 42d, respectively. The arginine requirement also increased in broilers fed diets without antibiotics. Ruan et al. (2020) demonstrated that growth performance of Qingyuan partridge chickens, which belong to the yellow-feathered broilers, was improved by increasing dietary Arg from 8.5 to approximately 12.0 g/kg in antibiotic-free diets. The study also showed that ileal secretary IgA levels were increased by Arg supplementation. Secretory IgA is the primary immunologic barrier preventing intraluminal pathogens from colonizing the intestinal mucosa, and this aids in maintaining homeostasis with the commensal microbiota. It may be expected that arginine plays important roles in intestinal health and immunity.

The Arginine Requirement Increases in Heat Stress
From market application experience, the requirement for arginine in broilers is different in different seasons. In the summer, nutritionists might appropriately increase the arginine level of the diets in order to avoid poor growth performance. A trial run by Sirathonpong et al. (2019) studied increasing arginine:lysine (Arg:Lys) requirement at high temperatures. Ross 308 broilers were reared under 27-30℃ and fed 5 different diets with Arg:Lys of 0.85, 0.95, 1.05, 1.16, and 1.26. Trial resulted in consistent improvements in feed conversion without any loss in growth and meat yield (results shown in Figure 2). Under heat stress, the organs such as the small intestine, liver, and spleen are experiencing ischemic and hypoxic conditions. Arginine was shown to have an important role in vasodilation and adversely changing blood flow. That may be why arginine plays a functional role under heat stress.

FUNCTIONAL EFFECT OF ARGININE IN BROILERS
Improve Intestinal Health
Zhang (2018) conducted six experiments to study the effects of L-arginine supplementation on the intestinal mucosal injury induced by the intestinal pathogenic bacteria in broiler chickens and related mechanisms. One experiment demonstrated L-arginine supplementation could inhibit Clostridium perfringens overgrowth and alleviate intestinal mucosal injury by promoting innate responses and maintaining intestinal barrier function. Dietary L-arginine supplementation prevented C. perfringens challenge-induced circulating arginine deficiency and normalized arginine transport and metabolism. L-arginine also plays a role in downregulated the activated JAK-STAT (jejunal Janus kinase, signal transducer and activator of transcription) signaling pathway. In another, L-arginine alleviated the intestinal inflammation and mucosal injury of chicken challenged by Clostridium perfringens. The arginine supplemented diet fed during the whole period exhibited more beneficial effects than that only fed during the infection stage.

Improve Immunity
Tan (2014) studied the effects of dietary L-arginine supplementation on growth performance, immunosuppression, inflammation, and intestinal barrier dysfunction in broiler chickens. The results demonstrated that additional dietary arginine supplementation is required to get the optimal growth performance and immune function for immunosuppressive broilers, and arginine supplementation attenuated IBDV (Infectious Bursal Disease Vaccine) inoculation induced immunosuppression via modulating circulating T cell subpopulations. Dietary arginine supplementation attenuated intestinal mucosal disruption of coccidiosis-challenged chickens probably through suppressing TLR4 and activating mTOR complex 1 pathway, and attenuated the overexpression of pro-inflammatory cytokines probably through the suppression of the TLR4 pathway and CD14+ cells percentage.

CONCLUSION
As an amino acid, arginine in poultry is essential. It plays a nutritional and functional role in broilers. The requirement of arginine is increased in antibiotic-free diets and during heat stress in order to ensure the growth performance of broilers.

About Xiaoli Dong
Getting her Ph.D in animal nutrition from the Chinese Academy of Agricultural Sciences, Xiaoli Dong joined CJ BIO China in 2015 working in the amino acid technology department. Now, she works as a technical director and is responsible for the application and promotion of small variety amino acid in Chinese markets.

Arginine in broilers: Enhancing growth, immunity, and heat stress resilience yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Heat stress compromises gut barrier function, creating favoring conditions for Clostridium perfringens proliferation and increased enteritis risk in broilers. Research demonstrates that specialized dietary solutions enhance mucosal integrity and tight junction protein expression while reducing pathogen load—translating to improved feed efficiency under challenging conditions. These findings reveal practical nutritional strategies that preserve gut homeostasis and maintain performance when temperatures rise.

Broiler production faces significant challenges when it comes to maintaining gut health and productivity, especially under heat stress conditions. One of the primary concerns is the increased risk of enteritis risk in broilers, driven by Clostridium perfringens proliferation and the development of necrotic enteritis, an important disease that can have severe consequences on broiler performance and producers’ profitability.

HEAT STRESS: OPENING THE DOOR TO CLOSTRIDIUM PERFRINGENS
Clostridium perfringens (C. perfringens) is an opportunistic pathogen that multiplies in the intestinal tract of broilers, particularly when there are excesses of nutrients and the gut barrier is compromised. Under heat stress conditions, broilers can have a cascade of physiological reactions such as the decrease of feed intake, poor nutrients’ absorption, furthermore in the broilers’ gut there can be disruption of the intestinal barrier function. All these changes can create favorable conditions allowing C. perfringens to proliferate and produce its potent toxins. The over-population of C. perfringens and its toxins can damage the intestinal epithelial cells, leading to necrosis and inflammation. This disruption of the intestinal barrier facilitates the bacteria and their toxins to penetrate deeper into the intestinal wall, further exacerbating the damage on broilers’ health and productivity.

YEAST POSTBIOTIC’S PROVEN CONSISTENT EFFECTS
Preserving Gut Health
Numerous studies have shown that Safmannan^®, a premium quality yeast postbiotic, has positive impact on the preservation of the broiler’s gut barrier and the reduction of Clostridium perfringens load in the intestinal tract, under various challenging conditions including heat stress challenge.

The intestinal environment represents a critical interface between nutrition and health. When this environment is compromised due to heat stress, it creates a pathway for pathogens to proliferate, leading to inflammation and reduced nutrient absorption. Maintaining physiological balance at the gut level is therefore essential for efficient feed conversion and growth in commercial poultry operations.

Cheng et al. observed that Safmannan^® has the ability to help heat stressed-birds preserving their gut barrier and function, by increasing Mucin 2 secretion – main component of mucus, and gut tight junction proteins such as claudin-5. The same effects have been observed by Bungo et al. Birds in Safmannan^® group, challenged by heat stress, exhibiting significant higher levels of Mucin 2 and claudin-5, compared to the ones in both non-challenged group and heat stress-challenged group (Figure 1 and 2).

This indicates that Safmannan^® helps preserve the birds’ gut barrier integrity and proper function under heat stress conditions.

Reducing Clostridium Perfringens Load
Various environmental and management factors can disrupt homeostasis in poultry, with heat stress being particularly problematic in many regions. When birds experience heat stress, they activate physiological mechanisms to dissipate heat, which often comes at the expense of productive functions. The resulting imbalance can lead to reduced feed intake, impaired gut function, and increased susceptibility to pathogens like C. perfringens.

Modern poultry production requires a deep understanding of these biological mechanisms to implement effective interventions. By supporting natural homeostatic processes, producers can minimize the negative impacts of stress factors and maintain optimal performance.

Santovito et al. have studied the effectiveness of Safmannan^® in adsorbing Clostridium perfringens. The researchers used an equilibrium isotherm approach to measure the capability of Safmannan^® to adsorb C. perfringens. The study found that Safmannan^® can effectively absorb C. perfringens in a dose- and time-dependent manner, with high affinity and capacity. The researchers also observed that the adsorption of C. perfringens by Safmannan^® resulted in a reduction in the viability of the pathogen. This suggests that the antimicrobial activity of Safmannan^® against C. perfringens can be attributed to an adsorption mechanism, where the yeast postbiotic components bind to the bacterial cells and interfere with their metabolic functions.

Furthermore, Alqhatani et al. demonstrated that adding Safmannan^® to broilers’ diet can significantly decrease Clostridium perfringens load in the gut of broilers reared under natural heat stress conditions, compared to the challenged, non-supplemented birds (Figure 3).

Improving Poultry Performance
In addition to its positive effects on gut barrier preservation and Clostridium perfringens reduction, Safmannan^® has also been shown to help mitigate the detrimental effects of heat stress on broiler productivity. Multiple trials conducted in different regions around the world have demonstrated Safmannan^® capacity to improve feed conversion ratios (FCR) and survival rates in broilers under severe heat stress conditions (Figure 4).

These improvements align with the fundamental principle that maintaining homeostasis leads to improved feed efficiency and better growth rates. When birds can allocate energy to productive functions rather than combating stress and pathogens, the economic benefits become evident through enhanced performance metrics.

By preserving gut integrity and reducing the risk of enteritis in broilers, Safmannan^® enables broilers to better withstand the challenges of heat stress and maintain optimal performance. This makes Safmannan^® a valuable tool in the battle against the negative impacts of heat stress in broiler production.

Implementation of management practices that support homeostatic balance is increasingly recognized as essential in modern poultry production. Nutritional strategies, including the use of specialized dietary solutions like Safmannan^®, represent an effective approach to helping birds maintain physiological equilibrium even under challenging conditions.

Environmental controls that minimize stress are equally important, as they work synergistically with nutritional interventions to support optimal functioning. The economic benefits of supporting natural homeostatic processes translate directly to improved profitability, making these approaches highly relevant to poultry producers.

CONCLUSION
In conclusion, Safmannan^® has been shown to be an effective solution in preserving the gut barrier and reducing the risk of Clostridium perfringens-induced enteritis in broilers under heat stress conditions. By adsorbing the pathogen and reducing its viability, Safmannan^® helps maintain the integrity of the intestinal barrier and enables broilers to better withstand the challenges of heat stress. The incorporation of Safmannan^® into broiler heat stress management can enhance the resilience of the flock, optimize production efficiency, and ultimately, improve the profitability of broiler operations.

References
1. Cheng, Y. et al. (2019). Effects of Saccharomyces cerevisiae fermentation product on growth performance, intestinal barrier function, and immune response of broilers under heat stress. Poultry Science, 100(1), 100805
2. Bungo et al., (2021), Evaluating the effect of Safmannan^® supplementation on broiler chicks subjected to high ambient temperature, WPC 2021
3. Santovito, E. et al. (2019). Equilibrium Isotherm Approach to Measure the Capability of Yeast Cell Wall to Adsorb Clostridium perfringens. Foodborne Pathogens and Disease, 16(9), 1-8
4. Alqhatani, H. et al. (2024). Dietary supplementation of prebiotic yeast Saccharomyces cerevisiae cell wall promotes

About Dr. Alain Riggi
With extensive field experience as Chief Veterinarian in various poultry production companies, Dr. Alain Riggi joined MSD Animal Health in 2010. Since then, he has held several key roles, including Poultry Technical Director for Europe and North & West Africa. As poultry veterinarian, one of Dr. Riggi’s core missions at Phileo by Lesaffre is to help large poultry producers in the world (US, China, EU, Brazil, Thailand, etc.) to identify the issues in their farms and provide solutions.

About Lin Wang
With over 15 years of experience in animal nutrition and health, including a decade specializing in the poultry sector, Lin Wang brings deep expertise to her role at Phileo by Lesaffre. She is passionate about advancing quality protein solutions to address global nutritional challenges. Through her work, Wang contributes to developing sustainable animal production systems that enhance both producer profitability and animal welfare, aligning scientific innovation with practical industry needs.

Preserving gut integrity and reducing enteritis risk in broilers under heat stress yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Digestible arginine requirements in broilers have traditionally focused on specific ratios to lysine, but emerging research highlights benefits of exceeding historical norms. Higher ratios have shown positive effects on growth, immunity, gut health, and even resilience during heat stress and enteric challenges. The article explores how arginine’s multifunctional roles may be more critical than previously assumed—especially under stress conditions.

By Dr. Chance Williams, Director of Nutrition, Wayne Sanderson Farms Inc.
      Dr. Jason Lee, Product Development Director, CJ Bio America
Historically, nutritionists have used formulating ratios for digestible arginine to digestible lysine (dArg:dLys) between 103% and 107% for broilers. However, recent research has reported that ratios above 107% can have beneficial impacts on performance, health and stress. Benefits include additional body weight gain, efficiency and carcass yield by increasing the dArg:d Lys ratio to 112-115%. Additionally, elevated levels of dArg:dLys demonstrated improvements in intestinal function and integrity during an enteric challenge, as well as performance during protozoal and bacterial infections. The functional properties of arginine have also shown to assist the health and well-being of poultry when reared in elevated temperatures. Increasing arginine concentration above historical norms appears to better meet the nutritional requirement of poultry and prevents growth performance losses due to prioritization of this important nutrient to metabolic pathways other than growth.

ARGININE IS A FUNCTIONAL AMINO ACID
Arginine is an essential amino acid for broilers, known for its direct influence on growth (Kidd et al., 2001), immunity (Collier and Vallance, 1989), tissue healing (Efron and Barbul, 1998), and carcass traits (Corzo et al., 2003). Arginine is the most versatile amino acid and is involved in numerous physiological functions, serving as a substrate for the biosynthesis of nitric oxide, creatine, glutamine, glutamate, and ornithine (Khajali and Wideman, 2010). Arginine modulates the immune response directly through the production of nitric oxide and ornithine (Le Floc’h et al., 2004) and promotes the proliferation of lymphocytes in Peyer’s patches and stimulates the secretion of anabolic hormones such as growth hormone and insulin-like growth factor-1 which promote protein synthesis and wound healing. Nitric oxide acts as a cytotoxic mediator of immune-activated cells and regulator of the immune system (Hibbs et al., 1988). Arginine also serves as a precursor for the synthesis of polyamines, which are important for cell division and gene expression (Le Floc’h et al., 2004).

In a recent evaluation of the optimal ratio of arginine to lysine in Ross 708 broiler males, Corzo et al., (2021) observed that the ratio needed to optimize body weight gain, feed conversion ratio, and breast meat weight was 129%, 116%, and 112% respectively (Figure 1). Corzo et al. (2021) also reported linear increases in thigh weight and yield with increasing arginine ratio during the finisher phase, concluding higher dArg/dLys needs as the bird ages are likely due to the considerably high maintenance value of arginine in broilers. Performance enhancement with increasing arginine to lysine ratios were also reported by Oliveira et al., (2022) with a linear increase in body weight with arginine ratios ranging from 96% up to 124% of dLys with similar linear reduction in feed conversion ratio in Cobb 500 broilers. Anderson et al., (2023) also reported linear effects on body weight with increasing arginine ratios in Cobb 500 broilers.

Interestingly, Oliveira et al., (2022) evaluated an arginine dose response on skin thickness and strength in addition to the increasing arginine impact on muscle creatine level. The authors reported a linear increase in skin thickness (sampled from the left and right pelvic back region) and skin strength at 44 days of age as arginine ratio was increased from 94% to 124% of dLys. The highest evaluated arginine level of 124% of dLys resulted in a skin thickness of 1.211 mm and a strength of 10.171 mm as compared to 0.898 mm thickness and 5.154 mm strength from broilers fed a diet containing an Arg ratio of 106% of dLys, which is historically considered the requirements in broilers. The authors concluded that mitochondrial arginase located in the kidney can hydrolyze arginine into ornithine (Furakawa et al., 2021) and then ornithine into proline by the enzyme ornithine-aminotransferase. This benefit in skin quality could have significant impact on broiler health and wellbeing during grow out, as well as economic importance due to improved performance, less disease challenge, and decreased condemnations during processing. Andeson et al., (2024;2025) reported in two separate studies that increasing dietary arginine led to linear increases in serum ornithine levels, thus supporting the conclusions put forth by Oliveira et al. (2022).

IMMUNOLOGICAL BENEFITS
Fathima et al., (2024) demonstrated the immunological modulating effects of arginine during gastrointestinal challenge as an increase in dietary arginine decreased the CD8+:CD4+ T-cell ratio and down regulated the expression of inflammatory cytokines and enzymes preventing inflammatory injury to the tissues during necrotic enteritis challenge in broilers. The beneficial immunological impacts of elevated arginine ratios were also documented by Yazdanabadi et al., (2020), who reported that increasing the dietary arginine concentration to 125% of recommended levels increased nitric oxide and decreased pro-inflammatory cytokines in coccidiosis challenge broilers. This immunomodulation effects of arginine resulted in improved growth performance compared to 100% recommended arginine levels (Yazdanabadi et al., 2020). This downregulated expression of inflammatory cytokines and enzymes could prevent inflammatory tissue injury during enteric intestinal challenge.

Anderson et al., (2023) also observed effects on the immune system when feeding increasing levels of digestible arginine in addition to improvements in growth performance. In a dose response study with dArg:dLys ratios between 80% and 133%, quadratic analysis determined that the optimal ratio to maximize body weight gain and feed conversion ratio (95% of vertex) in Cobb 500 broilers was 116%. Additionally, following an LPS challenge, the infiltration of heterophils, production of nitric oxide and the ratio of heterophils to lymphocytes increased linearly with increasing arginine concentration. These data support the fact that arginine plays a pivotal role in the initiation of the immune response against a foreign antigen.

These immunomodulatory effects of arginine could benefit production animals during times of enteric challenge and allow improved growth performance and ability to effectively fight and clear a pathogenic infection. Necrotic enteritis is an economically important disease in broiler chickens causing intestinal damage and loss of performance. Zhang et al., (2019) demonstrated the antipathogenic properties of arginine in a necrotic enteritis model. Intestinal infection via a direct challenge resulted in significant lesion development and Clostridium perfringens recovery in the liver. The addition of L-arginine to increase the ratio to 123% of dLys significantly decreased Clostridium perfringens recovery in the liver, as well as observed lesion score in challenged broilers (Figure 2 -adopted from Zhang et al., 2019). Wang et al., (2024) reported the benefits of increasing arginine concentration on Clostridium perfringens’ α toxin-induced intestinal injury in broilers. Feeding increased levels of arginine increased broiler body weight, increased serum IgA and IgG, increased villus height and reduced crypt depth, decreased IL-1β, IL-6, and IL-17 and increased mTOR expression. Figure 2 (adopted from Wang et al. (2024) illustrates the beneficial impact of L-arginine supplementation on intestinal morphology during a challenge situation and the improved gastrointestinal health with longer and healthier villi and shorter crypt depth. This was observed simultaneously with reductions in proinflammatory cytokines and activation of the SLC38A9/mTORC1 pathway. Anderson et al., (2025) also reported benefits of increasing arginine level during a necrotic enteritis challenge as they evaluated a dose response of digestible arginine ratio to digestible lysine ranging from 80 to 150 in Ross 708 broilers subjected to a necrotic enteritis challenge model. Anderson et al., (2025) reported a linear decrease in broiler FCR during the recovery phase of challenge with increasing arginine concentration and reported an optimal arginine ratio for FCR during the dose response period of 123% dArg:dLys. These series of experiments provide a comprehensive view of the immunomodulatory potential of arginine administration and a mode of action for the induced performance benefits during challenge.

HEAT STRESS
The ability of elevated levels of arginine to provide benefits to poultry when experiencing heat stress is not a new concept. Brake et al., (1998) demonstrated that increasing the digestible arginine concentration positively benefited broiler body weight during periods of elevated temperatures. However, at the time of this publication in 1998, a commercially available option for a concentrated form of arginine was not available. With the introduction of feed grade L-arginine since 2016, dietary arginine concentrations can now be easily adjusted. Anderson et al., (2024) conducted an arginine dose response in broilers that were subjected to cyclic elevated temperatures (32 vs. 24 °C) in an effort to replicate summer conditions. In their study results, broilers fed increasing Arg ratios had linearly reduced cloacal temperatures at 46 days of age. This effect on core body temperature directly correlated with a linear reduction in observed feed conversion ratio and quadratic effects on breast meat yield with the apex of breast yield occurring at a ratio of 116%. These data demonstrate that the functional properties of arginine benefited the bird’s ability to handle elevated temperatures while providing sufficient arginine to maintain growth performance and yield.

CONCLUSIONS
Arginine is the most diverse essential amino acid necessary for numerous metabolic pathways that are essential for the health and wellbeing of an animal. Its roles in immunological functions, nitric oxide production, polyamines, creatine, proline synthesis and antioxidant capacity are vital to the ultimate performance of poultry and economic return. Due to the importance of these roles in health and wellbeing, providing less than adequate amounts of dietary arginine will force the animal to prioritize and potential lack sufficient amounts of arginine necessary for optimal economic performance, growth and yield.

References
1. Anderson, A., C. Beck, J. Santamaria, J. Lee, R. Adhikari, S. Rochell, and G. Erf. 2023. Influence of dietary arginine on local and systemic inflammatory responses to lipopolysaccharide in broilers. Poultry Science Association Annual Meeting. Philadelphia, PA. July 17, 2023
2. Anderson, A., J. Lee, R. Adhikari, and S. Rochell. 2024. Dietary arginine responses of Ross 708 broilers reared under cyclic elevated temperatures. International Poultry Scientific Forum. Alanta, GA. January 29, 2024
3. Anderson, A. J. Lee, R. Adhikari, R. Hauck, and S. Rochell. 2025. Dietary arginine response of Ross 708 broiler subjected to enteric challenge with Eimeria spp. And Clostridium perfringens. International Poultry Scientific Forum, Atlanta, GA January 27, 2025
4. Brake, J., D. Balnave, and J. Dibner. 1998. Optimum dietary arginine:lysine ratio for broiler chickens is altered during heat stress in association with changes in intestinal uptake and dietary sodium chloride. British Poultry Science 39:693-647. doi:10.1080/00071669888511
5. Collier, J., and P. Vallance. 1989. Second messenger role for NO widens to nervous and immune system. Trends Pharmacological Science. 10:427-431
6. Corzo, A., E. Moran, and D. Hoehler. 2003. Arginine need of heavy broiler males: applying the ideal protein concept. Poultry Science 82:402-407
7. Corzo, A., J. Lee, J. Vargas, M. Silva, and W. Pacheco. 2021. Determination of the optimal digestible arginine to lysine ratio in Ross 708 male broilers. Journal of Applied Poultry Research. 30:100136
8. Efron, D. and A Barbul. 1998. Modulation of inflammation and immunity by arginine supplements. Current Opinion in Clinical Nutrition and Metabolic Care 1:531-538
9. Fathima, S., W. Al Hakeem, R. Shanmugasundaram, and R. Selvaraj. 2024. Effect of arginine supplementation on growth performance, intestinal health, and immune response of broilers during necrotic enteritis challenge. Poultry Science 103:103815
10. Le Floc’h, N., D. Melchior, and C. Obled. 2004a. Modifications of protein and amino acid metabolism during inflammation and immune system activation. Livestock Production Science 87:37-45
11. Khajali, F., and R. F. Wideman. 2010. Dietary arginine; metabolic, environmental, immunological, and physiological interrelationships. World’s Poultry Science Journal 66:751-766
12. Kidd, M, E. Peebles, S. Whitmarsh, J. Yeatman, and R. Wideman. 2001. Growth and immunity of broiler chicks as affected by dietary arginine. Poultry Science 80:1535-1542
13. Oliveira, C., KK. Dias, R. Bernardes, T. Diana, R. Rodrigueiro, A. Calderano, and L. Albino. 2022. The effects of arginine supplementation through different ratios of arginine:lysine on performance, skin quality and creatine levels of broiler chickens fed diets reduced in protein content. Poultry Science 101:102148
14. Wang, X., T. Zhang, W. Li, H. Wang, L. Yan, X. Zhang, L. Zhao, N. Wang, and B. Zhang. 2024. Arginine alleviates Clostridium perfringens α toxin-induced intestinal injury in vivo and in vitro via the SLC38A9/mTORC1 pathway. Frontiers in Immunology. 10.3389/fimmu.2024.1357072
15. Yazdanabadi, F., G. Moghaddam, A. Nematollahi, H. Daghighkia, and H. Sarir. 2020. Preventative Vererinary Medicine 180:105031
16. Zhang, B., L. Gan, M.S. Shahid, Z. Lv, H. Fan, D. Liu, and Y. Guo. 2019. In vivo and in vitro protective effect of arginine against intestinal inflammatory response induced by Clostridium perfringens in broiler chickens. Journal of Animal Science and Biotechnology. 10:73. https://doi.org/10.1186/s40104-019-0371-4

New insights on digestible arginine requirements in broilers yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Micro encapsulated phytogenics are transforming poultry nutrition, moving beyond early herbal blends toward precision formulations that stabilize active compounds and target their release in the digestive tract. These innovations promise improved feed efficiency, growth performance, and gut health while addressing handling and processing challenges. Trials show measurable economic benefits, yet the full potential of combining plant and marine bioactives continues to evolve, inviting further exploration.

THE CHANGING FACE OF PHYTOGENICS
In the 1980s and 1990s, when phytogenic feed additives first emerged on the market, they were greeted as a natural and promising alternative to antibiotic growth promoters (AGPs). Formulated from herbs, spices, and other aromatic plants, these early blends brought a welcome “green” dimension to poultry production. They were embraced for their antimicrobial effects, ability to stimulate digestion, and potential to improve feed efficiency. But they were also products of their time – created with limited manufacturing technologies, reliant on volatile compounds that often degraded during feed processing, and typically built on formulations shrouded in mystery. For many years, the sector saw incremental progress rather than transformational change.

The global ban on AGPs brought phytogenics into the spotlight, especially in broiler production, where nutritionists sought natural tools to close the performance gap left by antibiotics. These plant-based solutions broadened their scope: They could modulate gut microbiota, reduce inflammation, stimulate enzyme activity, and strengthen gut lining integrity. Yet, despite their promise, first-generation phytogenics were hampered by three recurring challenges: Stability during feed processing, palatability and handling safety, and a lack of transparent formulation backed by solid scientific evidence.

Today, the sector stands at a turning point. The market is no longer satisfied with generic herbal blends that depend on marketing rather than measurable results. Instead, poultry producers are demanding precision, consistency, and proof. This has given rise to a second generation of phytogenics, products designed with advanced extraction techniques, rigorous quality control, and above all, manufacturing innovations such as micro-encapsulation that allow active compounds to survive processing and reach their target site in the digestive tract. This shift is not just a matter of science; it is transforming poultry farm economics by delivering higher feed efficiency, better growth rates, and measurable returns on investment.

MOVING BEYOND THE “BLACK BOX” ERA
The early generation of herbal blends reflected the technological capabilities of their time. Simple grinding, milling, or crude distillation were used to obtain plant extracts, but these methods often failed to protect sensitive molecules from the heat, moisture, and pressure of feed manufacturing. Volatile oils would evaporate, phenolic compounds would oxidize, and efficacy could vary dramatically from one batch to the next. Worse, many products were dusty and irritant for feed mill workers, and their strong aromas sometimes reduced feed intake in poultry.

Modern poultry farming demands more. Today’s second-generation phytogenics address these shortcomings with a combination of scientific transparency and cutting-edge processing. One of the most transformative innovations is micro-encapsulation. Unlike simple coating, which offers limited protection, micro-encapsulation allows active ingredients to be embedded in a protective matrix. This stabilizes volatile compounds during storage and processing, ensures uniform distribution in feed, and enables targeted release exactly where they are most effective; usually in the small intestine, where nutrient absorption is most critical.

This precision is particularly valuable in poultry farming; indeed without targeted release, much of a phytogenic’s potential can be lost before it can act. Encapsulation also solves key safety and handling issues. Dust-free granules improve working conditions in feed mills, while the controlled aroma prevents negative effects on feed intake. Nuqo’s solution lies in XPR Technology, a proprietary micro encapsulation process that physically protects these sensitive bioactives and delivers them where they are needed most in the animal’s gastrointestinal tract. Unlike simple coatings or standard encapsulation, XPR creates multiple protective layers, ensuring thermal stability during pelleting or extrusion, preserving efficacy, targeted release in the intestine, where bioactives can exert the greatest effect and synergistic action between plant and seaweed components, boosting immune function, modulating gut microbiota, and improving nutrient utilization (Figure 1).

The technological leap is not only in the delivery system but also in the source of active molecules. While plants remain at the core of phytogenic development, the exploration of marine algae (phycogenics) is opening new frontiers. Certain algae metabolites have shown unique effects on gut health and immunity, adding complementary modes of action to those of traditional herbs and spices. The combination of plant and algae bioactives, delivered through robust micro-encapsulation, is setting a new industry standard for efficacy, stability, and profitability.

TRIAL RESULTS – MEASURING PERFORMANCE, PROVING PROFITABILITY
The transition from first-generation herbal blends to high-precision phytogenics is not just theoretical. Trials around the world have repeatedly demonstrated the tangible benefits of these advanced formulations in commercial poultry production. One example is Nuqo NEX (NQ), a second-generation solution combining high concentrations of active metabolites from both plants and marine algae, protected by proprietary micro-encapsulation technology. The formulation ensures superior concentration and stability compared to conventional solutions, integrating phytogenic compounds derived from thyme, cinnamon, and clove with phycogenic bioactives from Ascophyllum nodosum.

In a 39-day trial at the University of Arkansas, male Cobb 500 broilers were raised on a standard US three-phase diet (Starter, Grower, Finisher). Starter feeds were pelleted and crumbled, while Grower and Finisher diets were fed as pellets – conditions that typically challenge the stability of volatile phytogenic compounds. NQ was applied at 100 g/ton from day 0 to day 39 in the treatment group, while the control group received the basal diet only (Figure 2).

By the end of the trial, control birds achieved body weight gains close to their genetic potential. Yet, the NQ group gained an additional 57 grams per bird and improved feed conversion ratio by 2.1 points compared to controls. In practical terms, this meant that the supplemented birds not only matched but exceeded their genetic performance expectations for body weight, while moving closer to optimal feed efficiency. Economic analysis, based on prevailing US feedstuff prices, calculated a return on investment of 3:1 for the farm, demonstrating that the additional cost of supplementation was more than offset by gains in performance.

Beyond growth and feed efficiency, NQ supplementation improved carcass and breast yields without increasing the incidence of meat quality defects such as woody breast or white striping. Other meat quality parameters, including pH, drip loss, and color, were unaffected, confirming that the performance improvements did not come at the expense of product quality.

This trial is part of a broader body of evidence, with over 30 studies worldwide documenting the benefits of this second-generation technology across broilers, layers, and other species. The consistency of results, across different diets, climates, and feed processing methods, highlights one of the most important advantages of high-precision phytogenics: they work reliably in real-world conditions, not just in laboratory settings.

A NEW STANDARD FOR POULTRY NUTRITION
The evolution of phytogenics from generic herbal blends to high-precision, micro-encapsulated formulations marks a decisive turning point in poultry nutrition. The first generation played an important pioneering role, introducing the concept of plant-based performance enhancers and paving the way for antibiotic-free production. But the demands of modern farming, greater transparency, consistent efficacy, worker safety, and demonstrable economic returns, have rendered many of these older solutions obsolete.

Second-generation phytogenics, exemplified by products like NQ technology, offer a fundamentally different value proposition. They combine carefully selected plant and algae bioactives, produced and processed with scientific precision, and delivered through micro-encapsulation that protects, stabilizes, and targets their activity. The result is a reliable improvement in performance metrics such as body weight gain and feed conversion, alongside enhanced meat yield and quality, all translating into measurable profitability for the farmer.

For an industry facing tight margins, volatile feed prices, and increasing consumer demand for sustainable production, these innovations are more than just an upgrade – they are a necessity. Continued research into new natural metabolites, coupled with further refinement of encapsulation and delivery technologies, promises to push the boundaries of what phytogenics can achieve.

The era of herbal blends as “black box” solutions is over. Poultry producers now have access to transparent, scientifically validated, and economically proven phytogenic technologies. The next decade will likely see these high-precision products become the norm, setting new standards for performance, profitability, and sustainability in poultry farming.

About Dr. Stephanie Ladirat
Currently working as Nuqo’s Technology Director, Dr. Stephanie Ladirat obtained her MSc degree in Food Technology with a specialization in Food Ingredient and Functionality and her PhD degree in Food Chemistry from Wageningen University (The Netherlands). During her PhD thesis, she studied in depth the human gut microbiota composition and its modulation upon prebiotic supplementation and/or antibiotic treatments. From 2014 till 2020, she worked at Cargill Animal Nutrition, first as technology lead for gut health additives and, then, as swine portfolio manager. She provided global technical product support for a broad range of products (phytogenics, organic acids, short and medium chain fatty acids, probiotics) and trained technical and sales teams. She most recently managed R&D projects and developed innovative feed additive solutions to answer specific customer needs related to animal gut health and performance.

Micro Encapsulated Phytogenics: Redefining poultry performance and profitability yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Feed pathogen control is a critical control point for Salmonella and other pathogens that compromise both food safety and production performance. Research analyzing multiple intervention strategies confirms feed contamination is both pervasive and persistent. Microbial-based interventions, postbiotics, bacteriophages, organic acid blends, heat treatment, and coarse grain diets demonstrate measurable effectiveness, while feed sanitizers provide both initial pathogen elimination and sustained recontamination protection.

Feed represents a key critical control point for Salmonella and other pathogens that compromise both food safety and production performance. As diagnostic capabilities advance through whole genome sequencing and CRISPR Sero-Seq technology, the question shifts from whether feed can harbor dangerous serotypes, to which interventions can effectively control them while preventing recontamination.

FEED CONTAMINATION DYNAMICS
Research analyzing multiple intervention strategies confirms that feed contamination with Salmonella is both pervasive and persistent (Bourassa et al, 2018; Chaney et al, 2022; Vilá et al, 2009). Historical data mapping Salmonella prevalence through feed mills shows contamination levels beginning at 27% during ingredient reception, decreasing to 6.5% immediately post-pelleting, then nearly doubling to 12.9% before loadout (Nape 1968; Hacking 1978; Jones 1991, 2004; Davies 1997; Whyte 2003). This recontamination pattern demonstrates that effective pathogen control must address both initial elimination and sustained protection throughout distribution.

Research has demonstrated that Salmonella serotypes isolated during poultry processing link to those found in feed mills, with studies showing over half of processing plant isolates trace back to feed sources (Corry 2002; Shirota 2000), reinforcing the need for comprehensive feed pathogen management strategies.

TREATMENT EFFICACY: THE EVIDENCE BASE
Microbial-Based Approaches
Microbial-based interventions operate through distinct mechanisms. Probiotics establish competitive exclusion by colonizing gut niches and producing antimicrobial compounds that create unfavorable conditions for pathogen growth.

Studies have shown that probiotic interventions demonstrate measurable effectiveness against Salmonella. For example, Knap et al (2011) documented that Bacillus subtilis DSM17299 achieved 58% reduction in Salmonella-positive samples while reducing cecal loads by 3 log units over 42 days. Vilá et al (2009) reported complete elimination in broilers (0% versus 42% in controls) using Bacillus cereus var. toyoi.

Postbiotics deliver bioactive metabolites and immunomodulatory factors that enhance intestinal barrier function and stimulate protective immune responses without requiring live organisms. Chaney et al (2022) found Saccharomyces cerevisiae-derived postbiotics reduced cecal prevalence from 12.2% to 3.4% (p = 0.0006) in a trial involving approximately 112,800 birds.

Bacteriophages provide highly targeted antimicrobial action through species-specific lysis of Salmonella cells while preserving beneficial microbiota. A study assessing bacteriophage delivery via feed achieved up to 100% reduction in some treatment groups with statistically significant load reductions (Thanki et al 2023).

NON-MICROBIAL APPROACHES
Organic acid blends can show measurable benefits. Bourassa et al (2018) found formic acid treatment (4 kg/ton over 6 weeks) reduced cecal positivity to 0% compared to 17% in controls, while combination treatments achieved 35% versus 60% positivity rates.

Physical modifications to feed can also demonstrate efficacy. Santos et al (2008) reported coarse grain diets resulted in lower cecal Salmonella loads (3.8-3.9 log MPN/g) compared to fine grain diets (4.4 log MPN/g), suggesting feed particle size represents an underutilized control parameter.

Treatments—including heat treatment and organic acids— act in feed to provide effective initial pathogen reduction but offer limited protection against recontamination during handling, transport, and storage.

Heat treatment exemplifies this limitation. While pelleting at 80-85°C for 20-40 seconds reduces general microbial load, it fails to achieve Salmonella elimination and provides no residual protection. Even extended protocols (6 minutes at 86°C) cannot prevent post-processing contamination from the moment the feed cools post-extrusion and during handling between mill and feeder.

Organic acids face similar constraints. Despite bacteriostatic properties and demonstrated efficacy at high inclusion rates, they do not actively protect feed from recontamination occurring during ingredient transport, mill processing, finished feed storage, delivery to farms, and bin-to-feeder transfer.

FEED SANITIZERS: ADDRESSING THE PROTECTION GAP
Over 40 years of research evidences that feed sanitizers represent the only commercially available solution providing both initial pathogen elimination and sustained recontamination protection. Wales et al (2013) documented that formaldehyde-based feed sanitizers, such as Termin-8®, effectively reduced Salmonella contamination while preventing recontamination throughout extended storage periods.

Recent Animal Plant and Health Agency work demonstrated that formaldehyde-free feed sanitizer, Finio®, controlled Salmonella more effectively at 1 kg/MT inclusion rates than organic acid blends applied at 6 kg/MT—significant for both efficacy and cost-effectiveness (Gosling et al., 2021). Research by Dr. Haraldo Toro expanded feed sanitizer effectiveness beyond bacteria, demonstrating avian influenza virus inactivation within feed matrices.

Feed sanitizers provide protection extending at least 14 days post-application, addressing the recontamination challenge limiting other strategies. This protection window covers typical mill-to-consumption timeframes, ensuring pathogen-free feed delivery to food-producing animals.

IMPLEMENTATION AND SELECTION CRITERIA
Continuous feed sanitation throughout the production cycle provides greater protection than partial approaches, as benefits accumulate over time to suppress pathogens more effectively. Early application is especially important, since exposure during initial gut development can establish long-lasting colonization that is difficult to control later. Collaborative research between Anitox and Colorado Quality Research has shown that birds receiving sanitized diets during critical windows may be better able to withstand enteric disease challenges, with lower mortality, reduced lesion scores and improved performance—highlighting the value of sustained, cycle-long interventions.

When evaluating feed pathogen control options, producers should consider two fundamental requirements:
Efficacy: Different treatments demonstrate varying capabilities against target pathogens. While some reduce general microbial load, specific pathogen elimination requires targeted approaches with documented effectiveness against Salmonella.

Sustained Protection: The feed mill and the extensive feed distribution network create ongoing recontamination risks from the point of extrusion in the mill all the way through to the feeder. Interventions providing residual protection offer advantages over those effective only at application point.

Feed pathogen management represents a practical component of comprehensive food safety programs. Research demonstrates multiple intervention categories can achieve measurable Salmonella reduction, with varying effectiveness and protection duration.

Producers implementing feed pathogen control strategies should evaluate options based on demonstrated efficacy, practical application requirements, and ability to maintain protection throughout the distribution chain. The goal remains straightforward: Ensuring feed quality at the mill translates to feed safety at the feeder.

As the industry optimizes production efficiency while maintaining food safety standards, evidence-based feed pathogen management strategies provide valuable tools for achieving both objectives simultaneously.

References
1. Al-Nass, A. Y., Al-Zenk, S. F., Al-Saff, A. E., Abdulla, F. K., Al-Baho, M., & Mashaly, M. (2011). Zeolite as a feed additive to reduce Salmonella and improve production performance in broilers
2. Bourassa, D., Wilson, K., Ritz, C., Kiepper, B., & Buhr, R. J. (2018). Evaluation of the addition of organic acids in the feed and/or water for broilers and the subsequent recovery of Salmonella Typhimurium from litter and ceca. Poultry Science, 97(1), 64-73
3. Chaney, W., Naqvi, S. A., Gutierrez, M., Gernat, A., Johnson, T., & Petry, D. (2022). Dietary inclusion of a Saccharomyces cerevisiae-derived postbiotic is associated with lower Salmonella enterica burden in broiler chickens on a commercial farm in Honduras. Microorganisms, 10(6), 1123
4. Knap, I., Kehlet, A. B., Bennedsen, M., Mathis, G., Hofacre, C., Lumpkins, B., Jensen, M. M., Raun, M., & Lay, A. (2011). Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers. Poultry Science, 90(12), 2787-2796
5. Santos, F. B. O., Sheldon, B. W., Santos, A., & Ferket, P. R. (2008). Influence of housing system, grain type, and particle size on Salmonella colonization and shedding of broilers fed triticale or corn-soybean meal diets. Poultry Science, 87(3), 405-420
6. Thanki, A., Hooton, S. P. T., Whenham, N., Salter, M., Bedford, M., O’Neill, H. M., & Clokie, M. R. J. (2023). A bacteriophage cocktail delivered in feed significantly reduced Salmonella colonization in challenged broiler chickens. Emerging Microbes and Infections, 12(1), 2181578
7. Vilá, B., Fontgibell, A., Badiola, I., Esteve-Garcia, E., Jiménez, G., Castillo, M., & Brufau, J. (2009). Reduction of Salmonella enterica var. Enteritidis colonization and invasion by Bacillus cereus var. toyoi inclusion in poultry feeds. Poultry Science, 88(5), 975-979
8. Wales, A. D., Carrique-Mas, J. J., Rankin, M., Bell, B., Thind, B. B., & Davies, R. H. (2010). Review of the carriage of zoonotic bacteria by arthropods, with special reference to Salmonella in mites, flies and litter beetles. Zoonoses and Public Health, 57(5), 299-314

About Dr. Alastair Thomas
With a PhD in Microbiology from the University of Bath, Dr. Alastair Thomas is the Global Head of Poultry Nutrition and Health at Anitox, where he leads a worldwide team of technical experts across 68 countries. A microbiologist by training, he focuses on optimizing poultry gut health, feed hygiene, and biosecurity, with particular expertise in early-life microbiome development and its impact on bird performance. He has contributed extensively to advancing antimicrobial-free production practices by highlighting the role of feed as a critical control point for pathogens such as Salmonella, Enterobacter, and Clostridia. Widely recognized as a thought leader in the field, Dr. Thomas integrates scientific research with practical, data-driven solutions to help producers safeguard flocks, improve nutrient absorption, and unlock the genetic potential of birds.

Feed Pathogen Control: Evidence-based approaches to salmonella reduction in poultry production yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Modern egg production is increasingly focused on the goal of a 100-week laying period and 500 eggs per hen, while maintaining consistent eggshell quality. As hens age, calcium metabolism and shell formation become critical limiting factors for productivity and profitability. Activated vitamin D supports efficient calcium absorption and mobilization, helping sustain eggshell strength and laying performance throughout extended laying cycles.

By Phytobiotics Futterzusatzstoffe GmbH
Commercial egg producers are striving to produce more eggs with adequate eggshell quality within one laying period of their hens. Some poultry farmers already achieve the target of 500 eggs in 100 weeks by adjusting breeds, management and nutrition. These are great examples of how modern hens can achieve performance goals unimaginable only 10-20 years ago. Active D Product Manager Murat Devlikamov explains:

WHAT IS THE BIGGEST CHALLENGE IN TERMS OF EXTENDED LAYING TIME?
Modern laying hens are truly high-performance animals that lay an egg almost every day. However, the eggs need to have a proper eggshell in order to be marketable; if this is not the case, economic losses are inevitable.

The eggshell requires calcium, which is mobilized from the feed and bones. The weight of the eggshell of the total egg mass remains relatively constant throughout the laying period as its share is genetically predetermined. Consequently, as the egg is getting larger, the eggshell is getting thinner. Considering the fact that the eggshell consists of 96% calcium carbonate the importance of calcium supply is evident to ensure stable eggshells. With age, shell thickness also decreases, because calcium availability reduces. As a result, the breaking strength of the eggshell declines and more and more eggs show cracks or abnormalities.

In the first half of the laying period, the percentage of broken eggs is neglectable, but increases in the second laying period and requires feeding-related or management measures.

HOW ACTIVATED VITAMIN D HELPS
It is not only the size of the egg that influences the breaking strength of the eggshell. It is also a proper absorption, mobilization and transport of calcium. Vitamin D is an essential molecule which activates calcium transport and influences its absorption rate. Because of the importance of both, a supplementation with vitamin D and calcium should be ensured throughout the whole production period. Unfortunately, it is not always the case, especially in older laying hens, as the function of organs such as liver and kidneys is impaired by environmental influences. The production of specific enzymes involved in the metabolization of vitamin D declines. The availability of calcium in bones also decreases as reserves are depleted. In this case plant based Active D may help as it provides the already activated vitamin D glycosides which are directly available for the hen.

Activated vitamin D offers the advantage that it does not require the vitamin D metabolic pathway and is therefore not dependent on enzymes or organs functionality. As a result, the mobilization of calcium from the feed is maintained in critical phases and more calcium is available for the formation of the eggshell.

A field study conducted by the University of Sydney and described below shows the positive effect of Active D in old hens.

USE OF ACTIVE D IN OLDER BROWN LAYING HENS
A total of 240 Hy-Line Brown layer hens, 55 weeks of age, were purchased from a commercial laying farm and housed in the high-rise layer facility at the University of Sydney’s Camden Campus. After an adaptation period of 5 weeks, during which the hens received standard commercial feed, the trial started. The animals were allocated into three groups. A control group with standard vitamin D levels in a control diet. Treatment 1 consisted of a control diet plus 75 g of activated vitamin D₃ product/ton of feed, while Treatment 2 consisted of the control diet plus 125 g of activated vitamin D₃ product/ton of feed. From the 60th week, following relevant data was collected, among others: Egg production, eggshell breaking strength, and eggshell thickness.

PROMISING RESULTS
In both treatment groups, shell thickness was maintained relatively throughout the trial, while dropped notably in the control birds at 80 weeks of age. Concurrently, supplementation of both concentrations of activated vitamin D₃ maintained eggshell thickness compared to the control diet, indicating that activated vitamin D₃ may counteract the decrease of shell thickness frequently observed as hens age, because it ensures the calcium absorption and transport to the eggshell. Significant improvements in relative shell weight and thickness indicate that supplementing activated vitamin D₃ in older laying hens may benefit eggshell quality. Additionally, a numerical increase of laying performance indicates that the overall productivity is maintained compared to the control group. This finding shows that Active D is a promising tool for egg producers to achieve the goal of 100 weeks and 500 eggs and thus enables longer economic production.

More eggs, stronger shells: The role of activated vitamin D yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Our understanding of how nutrition influences growth and resilience in poultry has greatly expanded in recent years. It is now clear that animal performance stems to a large extent from a balance between metabolism, immune function, and the gut microbiome. These systems interact continuously, and even small nutritional or environmental changes can shift the animals’ physiological response. This growing knowledge has encouraged the development of nutritional strategies and feed components that work through adaptive, non-antibiotic mechanisms. One recent proposed explanation for these responses has rapidly gained ground: hormetic modeling.

Hormetic modeling describes how small or moderate doses of nutritional components can activate beneficial adaptive responses (improved resilience or metabolic efficiency), while excessive doses become harmful. This idea parallels, largely speaking, Paracelsus’s famous principle: “The dose makes the poison.” In poultry nutrition, such hormetic patterns are well recognized in nutrients like trace elements (selenium, zinc) and specific amino acids (for example, arginine). At optimal levels, these nutrients support antioxidant defense, growth, and immune balance, whereas excessive intake may cause oxidative or metabolic stress
This review examines the hormetic principle and its application to modern poultry/swine feeding concepts, exploring how balanced nutrient design and controlled inclusion of bioactive compounds can strengthen cellular adaptation, improve stress tolerance, and enhance production efficiency.

HOW DO AGPs ACTUALLY WORK?
Despite AGP’s widespread historical use, the precise mechanisms by which subtherapeutic doses of antibiotics enhance animal productivity remained poorly understood. Recent advances in systems biology and mitochondrial research propose new answers, much needed to develop future advanced nutritional systems.

The traditional explanations for AGP efficacy have focused primarily on antimicrobial effects:
• reducing nutrient competition from microorganisms
• decreasing harmful bacterial metabolites
• improving gut wall morphology (thinner gut wall → better nutrient absorption)
• preventing subclinical infections

However, these mechanisms alone could not fully explain why different classes of antibiotics with diverse mechanisms of action produce similar growth-promoting effects (Gutierrez-Chavez et al., 2025).

Niewold (2007) hypothesized that the primary mechanism of AGPs is non-antibiotic anti-inflammatory activity, reducing the energetic costs of chronic low-grade inflammation. Inflammation diverts nutrients from growth toward immune responses, with cytokine production (particularly IL-1β, IL-6, and TNF-α) suppressing anabolic pathways (Kogut et al., 2018). AGPs appear to selectively inhibit pro-inflammatory cytokine production without completely suppressing immune function.

A paper published in 2024 by Fernandez Miyakawa et al. proposes that antibiotics at subtherapeutic levels act primarily through mitochondrial hormesis and adaptive stress responses, and not simply through antimicrobial activity. In this model, mitochondria act as bioenergetic hubs and signaling centers. Low-dose antibiotics trigger mild mitochondrial stress, which triggers the activation of adaptive protective pathways. This in turn induces mitokine release, leading to systemic adaptive responses improving growth, feed efficiency, and disease tolerance.

MECHANISM OF ACTION IN THE HORMETIC MODEL OF AGP EFFICIENCY
Hormesis is a biphasic mechanism whereby high doses are toxic, but low doses stimulate adaptive responses and are beneficial. In the case of AGPs, Fernandez Miyakawa et al. propose that low doses stimulate growth, stress resistance, and cellular repair.

KEY SIGNALING PATHWAYS
As Bottje et al. (2006, 2009) shows, efficient animals often have mitochondrial inner membranes that are less permeable to protons and other ions, allowing for more effective coupling between electron transport and ATP synthesis, which reduces energy loss through proton leak and maximizes the production of ATP per oxygen molecule consumed. Lower membrane permeability is influenced by factors like decreased membrane surface area per protein mass, specific membrane protein content (such as adenine nucleotide translocase), and fatty acid composition in the membrane phospholipids, all contributing to a tighter barrier that prevents unregulated electron or proton flow and supports higher energetic efficiency. Such features make mitochondria in efficient species more capable of maintaining membrane integrity and ATP generation, especially when facing environmental stress, as seen in freeze-tolerant animals whose mitochondria do not undergo damaging permeability transitions under extreme conditions.

Nrf2
Many AGPs interfere with mitochondrial protein synthesis and electron transport chain. At subtherapeutic levels, they cause a mild ROS (Reactive Oxygen Species) increase, which triggers the activation of redox-sensitive transcription factor Nrf2. Since Nrf2 regulates over 250 antioxidant, detoxification, and anti-inflammatory genes, the result is improved cell survival, redox balance, and tolerance to stress (Petri et al., 2012).

Mitokine production
Mitokines are “signaling molecules that enable communication of local mitochondrial stress to other mitochondria in distant cells and tissues” (Burtscher et al., 2023). Through fibroblast growth factor 21 (FGF21), growth differentiation factor 15 (GDF15), adrenomedullin2 (ADM2) etc, these stress signals are released systemically and coordinate tissue-wide responses, leading to improved growth and resilience.

INFLAMMATION AND DISEASE DEFENSE
While the negative side of antibiotic growth promoters is well researched and understood (Rahman et al., 2022), science can advance by isolating the positive effects and attempting to offer different pathways to the same benefits. One such lesson can be derived from understanding inflammation pathways and responses.

Chronic low-grade intestinal inflammation is common in modern poultry production, due to diet, microbiota shifts, high metabolic demands etc. This inflammation diverts energy from growth to immune responses.

AGPs reduce the energy costs of this inflammation in three main ways:
• Reduces inflammation through adaptive stress response
• Raising the threshold to trigger inflammation
• Promoting overall resilience, rather than simply killing pathogens

Fernandez Miyakawa et al. suggest, in this emerging model, that disease defense can operate two different actions: resistance to health challenges through reduction of the pathogen load (which is driven by the immune system and is energy costly); and overall resilience by reducing host damage without reducing the pathogen load. AGPs, the authors claim, mainly promote resilience by enhancing mitochondrial stress responses and tissue repair, i.e. more precisely:
• Direct mitochondrial stimulation in intestinal epithelial cells
• Systemic mitokine signaling coordinating organism-wide adaptive responses
• Selective microbiota modulation enhancing beneficial host-microbe interactions
• Improving resilience without immune system costs
• Metabolic optimization supporting growth and feed efficiency

In this context, “metabolic optimization” refers to the enhancement of metabolic processes within livestock or poultry to support efficient growth, feed conversion, and physiological resilience, without relying on immune-mediated pathways that are energetically costly. Scientific evidence shows that metabolic optimization involves improving nutrient assimilation, promoting more efficient energy production in tissues (such as mitochondrial ATP synthesis), and minimizing wasteful metabolic byproducts, resulting in reduced feed intake per unit of growth and better utilization of dietary nutrients (Rauw 2025, El-Hack 2025).

FUNCTION OF FEED ADDITIVES AND FEED COMPONENTS
Feed additives and feed components in many ways represent the complete other side of the spectrum from antibiotics, but are there some features where antibiotics and feed additives come close in their functions? There is a good case to be made for certain feed additives ultimately working in the animal to achieve similar benefits to the desirable, non-medicinal usage of AGPs. Especially with the emergent model of AGP mechanism described above, it is worth discussing how certain feed additives can support the same end goal: promoting animal resilience.

Lillejhoj et al (2018), Gutierrez-Chavez et al. (2025) and others outline the end-results such products must achieve:
• Growth performance & feed conversion efficiency
• Promotion of animal productivity under
real-world conditions
• Support gut homeostasis
• Non-adverse effect on the immune system
• Reduction of oxidative stress
• Support organism in mitigation of enteric inflammatory consequences

Within the hormetic model, possibly the most important systemic benefit is, in one phrase, promoting resilience. Phytomolecules have long been used, in human and animal medicine, for the same end goal. The mechanisms described below should naturally be seen with caution, as phytomolecule microbiome effects can be subtler and context-dependent. However, the substantiating literature has been increasingly accumulating on these specific topics.
1. Immunometabolic regulation
Phytomolecules demonstrate remarkably similar anti-inflammatory effects to what Niewold (2007) suggested was a primary mechanism of AGPs: non-antibiotic anti-inflammatory activity, reducing the energetic costs of chronic low-grade inflammation. Inflammation diverts nutrients from growth toward immune responses, with cytokine production (particularly IL-1β, IL-6, and TNF-α) suppressing anabolic pathways (Kogut et al., 2018). AGPs appear to selectively inhibit pro-inflammatory cytokine production without completely suppressing immune function. A similar effect can be observed with various types of phytomolecules, which significantly reduced pro-inflammatory and/or increased anti-inflammatory cytokine expression in animals challenged with several pathogens. The anti-inflammatory mechanism appears to involve inhibition of NF-κB activation and modulation of MAPK signaling pathways (Kim et al., 2010; Long et al., 2021).

2. Mitochondrial hormesis and energy metabolism
Fernández Miyakawa et al. (2024, see above) proposed that AGPs exert growth-promoting effects through mitochondrial hormesis – subtherapeutic antibiotic doses induce mild mitochondrial stress, triggering adaptive responses that enhance mitochondrial function, energy metabolism, and cellular resilience. This mechanism, while requiring further validation, explains why different antibiotics with diverse targets produce similar growth outcomes.

The mitochondrial stress response involves activation of the IL-6 receptor family signaling cascade, which regulates metabolism, growth, regeneration, and homeostasis in liver and other tissues (Perry et al., 2024). Subtherapeutic antibiotic exposure activates proteins involved in growth and proliferation through IL-6R gp130 subunit signaling, including JAK, STAT, mTOR, and MAPK pathways.

Phytomolecules demonstrate similar mitochondrial effects. Perry et al. (2024) showed that increased activity of AMPK, mTOR, PGC-1α, PTEN, HIF, and S6K can also be available via phytomolecule activity, suggesting enhanced anabolic metabolism.

Capsicum oleoresin supplementation in broilers increased jejunal lipase and trypsin activity, enhanced ileal amylase activity, improved jejunal morphology, and modulated immune organ development, indicating enhanced digestive efficiency and nutrient utilization (Li et al., 2022).

Compounds such as vanillin, thymol, eugenol have been shown to improve glucose and lipid metabolism through TRPV1 activation and mitochondrial function enhancement (Gupta et al., 2022; Zhang et al., 2017).

3. Gut microbiota modulation
AGPs selectively reduce specific microbial populations, particularly Lactobacillus species that produce bile salt hydrolase (BSH). Since BSH reduces fat digestibility and thus weight gain, AGP-mediated reduction of BSH-producing bacteria enhances energy extraction and growth (Lin, 2014; Bourgin et al., 2021).

Recent research by Zhan et al. (2025) using single-molecule real-time 16S rRNA sequencing demonstrated that therapeutic antibiotic doses (lincomycin, gentamicin, florfenicol, benzylpenicillin, ceftiofur, enrofloxacin) significantly altered chicken gut microbiota composition, with Pseudomonadota and Bacillota becoming dominant phyla after exposure. Different antibiotics produced distinct temporal effects on microbial diversity and community structure.

Phytomolecules exert targeted antimicrobial effects while promoting beneficial bacteria. Dietary supplementation with 800 mg/kg Capsicum extract in Japanese quails reduced cecal counts of pathogenic bacteria (Salmonella spp., E. coli, coliforms) while modulating Lactobacilli populations (Reda et al., 2020).

In pigs, 80 mg/kg natural capsicum extract increased cecal propionic acid and total volatile fatty acid concentrations, with increased butyric acid in the colon – indicating enhanced fermentation by beneficial bacteria (Long et al., 2021).

Capsicum and Curcuma oleoresins altered intestinal microbiota composition in commercial broilers challenged with necrotic enteritis, reducing disease severity through microbiome modulation (Kim et al., 2015).

Capsaicin demonstrates selective antimicrobial activity, inhibiting pathogenic Gram-negative bacteria while favoring development of certain Gram-positive bacteria. The antibacterial mechanism involves induction of osmotic stress and membrane structure damage (Adaszek et al., 2019; Rosca et al., 2020).

4. Intestinal barrier function and gut health
AGPs have been associated with improved intestinal morphology, including increased villus height and reduced crypt depth, which enhance absorptive capacity (Gaskins et al., 2002).

Phytomolecules produce similar or superior effects. Capsicum extract (80 mg/kg) in pigs increased ileal villus height and upregulated MUC-2 gene expression, indicating enhanced gut barrier function and integrity. The improved barrier function correlated with reduced diarrhea incidence (Liu et al., 2013; Long et al., 2021).

Allium hookeri extract increased expression of tight junction proteins (claudins, occludins, ZO-1) in LPS-challenged broiler chickens, demonstrating direct enhancement of barrier integrity (Lee et al., 2017).

5. Oxidative stress mitigation
Oxidative stress impairs growth by damaging cellular components and triggering inflammatory responses. AGPs reduce oxidative stress indirectly through anti-inflammatory effects and microbiota modulation (Bortoluzzi et al., 2021).

Phytomolecules possess direct antioxidant properties. Capsicum extract (50 mg/kg) in heat-stressed quails reduced serum and ovarian malondialdehyde (MDA) while increasing superoxide dismutase (SOD) and catalase (CAT) activities. Ovarian transcription factors showed decreased NF-κB and increased Nrf2 and HO-1 expression (Sahin et al., 2016).

A mixture of herbal extracts including pepper reduced thiobarbituric acid reactive substances and MDA in broiler liver and muscle, while increasing glutathione peroxidase (GSH-Px) activity and improving antioxidant enzyme expression (Saleh et al., 2018).

Capsicum extract (80 mg/kg) in pigs increased total antioxidant capacity, SOD, and CAT while reducing MDA levels, demonstrating robust antioxidant effects (Long et al., 2021).

STANDARDIZATION AND CONTROLLED RELEASE: CRITICAL SUCCESS FACTORS
A major criticism of phytomolecules has been inconsistent efficacy across studies. However, this variability largely reflects differences in:
• Active compound concentrations
• Bioavailability and stability
• Dosing precision
• Product quality and standardization

Microencapsulation is one of the technologies that address the standardization and bioavailability challenges. It protects volatile compounds from degradation during feed processing and storage, with encapsulated essential oils showing significantly higher retention compared to unprotected forms (Stevanović et al., 2018). By creating a protective barrier around active ingredients, microencapsulation enables controlled release in specific regions of the gastrointestinal tract, improving absorption efficiency and reducing dose variability (Bringas-Lantigua et al., 2011). The technology also masks unpalatable flavors that can reduce feed intake while standardizing active ingredient concentrations through precise manufacturing processes (Gharsallaoui et al., 2007). Studies demonstrate that spray-dried microencapsulated essential oils achieve encapsulation efficiencies exceeding 93% with minimal loss during storage (Hu et al., 2020), and can be engineered for enzyme-mediated release to ensure bioactive delivery at optimal intestinal sites (Elolimy et al., 2025).

MECHANISTIC SYNTHESIS: AN INTEGRATED MODEL
The evidence indicates that both AGPs and phytomolecules operate through an integrated network of effects:
1. Primary Level: Selective antimicrobial effects modify gut microbiota composition
2. Secondary Level: Reduced microbial metabolites (ammonia, endotoxins) decrease inflammatory signaling
3. Tertiary Level: Reduced inflammation conserves energy for growth; enhanced barrier function improves nutrient absorption
4. Quaternary Level: Mitochondrial hormesis and metabolic optimization increase energy efficiency
5. Systemic Level: Improved immunometabolic homeostasis supports optimal growth

This integrative model explains why multiple antibiotics with different mechanisms produce similar growth outcomes: they converge on common pathways regulating immunometabolism and mitochondrial function (Fernández Miyakawa et al., 2024).

Phytomolecules operate through the same mechanistic framework but with potential advantages:
• Multiple bioactive compounds providing redundancy
• Antioxidant effects enhancing stress resilience
• Lower AMR (Antimicrobial Resistance) selection pressure
• Potential prebiotic-like effects supporting beneficial microbiota

SAFETY AND ANTIMICROBIAL RESISTANCE CONSIDERATIONS
Antibiotic exposure significantly disrupts gut microbiota diversity and stability, with effects persisting beyond withdrawal periods. The study by Zhan et al. (2025) demonstrated that different antibiotics produce varying degrees of microbiota disruption, with florfenicol and gentamicin showing the strongest and most persistent effects.

In contrast, phytomolecules generally do not generate resistance through the same mechanisms as antibiotics. Some phytochemicals may actually enhance antibiotic efficacy and resensitize resistant bacteria through structural modifications of bacterial membranes (Khameneh et al., 2021; Suganya et al., 2022).

However, one study reported increased correlation between antibiotic resistance genes (ARGs) and mobile genetic elements in pig feces after mushroom powder supplementation, suggesting that certain phytogenic compounds may increase ARG mobility (Muurinen et al., 2021). This emphasizes the need for continued surveillance of phytomolecule effects on resistance gene dynamics.

Capsaicinoids and capsinoids have well-established safety profiles. Capsiate, a non-pungent analogue of capsaicin, exhibits substantially lower toxicity while maintaining similar metabolic and growth-promoting effects (Gupta et al., 2022). No adverse effects on animal health or product quality have been reported at recommended dosages in reviewed studies.

FUTURE DIRECTIONS AND RESEARCH NEEDS
Despite substantial progress, several areas require further investigation:
1. Mechanistic refinement: Detailed characterization of signaling pathways, particularly the IL-6R/gp130 cascade and mitochondrial stress responses
2. Precision formulation: Development of combinations optimized for specific production stages, environmental conditions, and disease pressures
3. Bioavailability optimization: Advanced delivery systems ensuring consistent active compound release and absorption
4. Microbiome-host interaction mapping: High-resolution characterization of microbial community shifts and their functional consequences
5. Economic validation: Large-scale production trials assessing cost-effectiveness compared to AGPs and disease management costs

CONCLUSIONS
The scientific evidence demonstrates that standardized phytomolecules operate through well-characterized biological mechanisms that substantially replicate those of AGPs:
1. Anti-inflammatory effects reducing energetic costs of immune activation
2. Mitochondrial hormesis enhancing energy metabolism and cellular resilience
3. Selective microbiota modulation supporting beneficial bacteria while controlling pathogens
4. Intestinal barrier enhancement improving nutrient absorption and reducing translocation
5. Antioxidant activity mitigating oxidative stress and supporting immune function

When properly standardized and formulated for controlled release, phytomolecules deliver growth promotion, feed efficiency improvements, and disease resistance comparable to AGPs, while potentially offering advantages in AMR risk profile, stress resilience, and consumer acceptance.

The mechanistic convergence between AGPs and phytomolecules, coupled with demonstrated efficacy in controlled trials, provides producers with confidence that science-based phytomolecular interventions represent legitimate alternatives to AGPs. Success depends on product standardization, appropriate dosing, and understanding that phytomolecules work through fundamental biological pathways rather than undefined or mystical mechanisms.

As the livestock industry continues to navigate the post-AGP era, standardized phytomolecules offer a scientifically sound, mechanistically validated approach to maintaining animal performance, health, and welfare while addressing antimicrobial resistance concerns.

References
1. Adaszek, Ł., et al. “Properties of Capsaicin and Its Utility in Veterinary and Human Medicine.” Research in Veterinary Science, vol. 123, 2019, pp. 14 – 19.
2. Bottje, W., et al. “Mitochondrial proton leak kinetics and relationship with feed efficiency within a single genetic line of male broilers”. Poultry Science, Volume 88, Issue 8, 1 August 2009, p. 1683-1693.
3. Bortoluzzi, C., et al. “A Protected Complex of Biofactors and Antioxidants Improved Growth Performance and Modulated the Immunometabolic Phenotype of Broiler Chickens Undergoing Early Life Stress.” Poultry Science, vol. 100, 2021, p. 101176.
4. Bourgin, M., et al. “Bile Salt Hydrolases: At the Crossroads of Microbiota and Human Health.” Microorganisms, vol. 9, no. 1122, 2021.
5. Bravo, D., et al. “A Mixture of Carvacrol, Cinnamaldehyde, and Capsicum Oleoresin Improves Energy Utilization and Growth Performance of Broiler Chickens Fed Maize-Based Diet.” Journal of Animal Science, vol. 92, 2014, pp. 1531 – 1536.
6. Bringas-Lantigua, M., et al. “Influence of Spray-Dryer Air Temperatures on Encapsulated Mandarin Oil.” Drying Technology, vol. 29, 2011, pp. 520–526.
7. Burtscher, J., et al. “Mitochondrial Stress and Mitokines in Aging.” Aging Cell, vol. 22, no. 2, 2023, e13770.
8. El-Hack, M. et al. “Integrating metabolomics for precision nutrition in poultry: optimizing growth, feed efficiency, and health”. Frontiers in Veterinary Science, Sec. Animal Nutrition and Metabolism, Volume 12 – 2025. https://doi.org/10.3389/fvets.2025.1594749
9. Elolimy, Ahmed A., et al. “Effects of Microencapsulated Essential Oils and Seaweed Meal on Growth Performance, Digestive Enzymes, Intestinal Morphology, Liver Functions, and Plasma Biomarkers in Broiler Chickens.” Journal of Animal Science, vol. 103, 2025, p. skaf092, https://doi.org/10.1093/jas/skaf092.
10. Fernández Miyakawa, Mariano E., et al. “How Did Antibiotic Growth Promoters Increase Growth and Feed Efficiency in Poultry?” Poultry Science, vol. 103, no. 2, 2024, article 103136. https://doi.org/10.1016/j.psj.2023.103136
11. Gaskins, H. Rex, C. T. Collier, and D. B. Anderson. “Antibiotics as Growth Promotants: Mode of Action.” Animal Biotechnology, vol. 13, no. 1, 2002, pp. 29 – 42.
12. Gharsallaoui, A., et al. “Applications of Spray-Drying in Microencapsulation of Food Ingredients: An Overview.” Food Research International, vol. 40, no. 9, 2007, pp. 1107-21.
13. Gutiérrez-Chávez, Vanesa, et al. “Capsaicinoids and Capsinoids of Chilli Pepper as Feed Additives in Livestock Production: Current and Future Trends.” Animal Nutrition, vol. 22, 2025, pp. 483 – 501. https://doi.org/10.1016/j.aninu.2025.03.014.
14. Gupta, A., et al. “Capsaicin and Capsinoids: Recent Updates on Their Health Benefits and Mechanisms of Action.” Phytotherapy Research, vol. 36, no. 5, 2022, pp. 1898 – 1912.
15. Hu, Q., Li, X., Chen, F., Wan, R., Yu, C.-W., Li, J., McClements, D. J., & Deng, Z. (2020). “Microencapsulation of an essential oil (cinnamon oil) by spray drying: Effects of wall materials and storage conditions on microcapsule properties”. Journal of Food Processing and Preservation, 44(11). https://doi.org/10.1111/jfpp.14805
16. Khameneh, B., et al. “Mechanisms of Antibiotic Resistance Resensitization by Phytochemicals: Review.” Phytomedicine, vol. 85, 2021, p. 153529.
17. Kim, D. K., et al. “Effects of Capsicum and Curcuma on Necrotic Enteritis in Broilers.” Poultry Science, vol. 94, 2015, pp. 2314 – 2321.
18. Kim, J. S., et al. “Anti-inflammatory Effects of Plant-Derived Molecules via NF-κB and MAPK Pathways.” International Immunopharmacology, vol. 10, no. 3, 2010, pp. 306 – 314.
19. Lee, S. H., et al. “Allium Hookeri Extract Enhances Tight Junction Proteins in Broilers.” Journal of Animal Physiology and Animal Nutrition, vol. 101, no. 1, 2017, pp. e48 – e56.
20. Li, X., et al. “Capsicum Oleoresin Supplementation Improves Digestive Enzyme Activity and Gut Morphology in Broilers.” Poultry Science, vol. 101, no. 7, 2022, p. 101844.
21. Lin, J. “Effect of Antibiotics on the Intestinal Microbiota and Their Role in Animal Growth.” Animal Biotechnology, vol. 25, no. 3, 2014, pp. 149 – 157.
22. Lillehoj, H., et al. “Phytochemicals as Antibiotic Alternatives to Promote Growth and Enhance Host Health.” Veterinary Research, vol. 49, no. 76, 2018.
23. Liu, Y., et al. “Dietary Capsicum Extract Enhances Intestinal Barrier Function and Growth in Pigs.” Journal of Animal Science, vol. 91, 2013, pp. 518 – 525.
24. Long, L., et al. “Phytogenic Feed Additives Modulate Intestinal Immunity and Antioxidant Status in Pigs and Poultry.” Frontiers in Veterinary Science, vol. 8, 2021, p. 620998.
25. Muurinen, J., et al. “Mushroom Powder Supplementation Increases Antibiotic Resistance Gene Mobility in Pig Feces.” Frontiers in Microbiology, vol. 12, 2021, p. 676678.
26. Niewold, T. A. “The Non-antibiotic Anti-inflammatory Effect of Antimicrobial Growth Promoters, the Real Mode of Action? A Hypothesis.” Poultry Science, vol. 86, 2007, pp. 605 – 609.
27. Perry, F., C. N. Johnson, L. Lahaye, E. Santin, D. R. Korver, M. H. Kogut, and R. J. Arsenault. “Protected Biofactors and Antioxidants Reduce the Negative Consequences of Virus and Cold Challenge by Modulating Immunometabolism via Changes in the Interleukin-6 Receptor Signaling Cascade in the Liver.” Poultry Science, vol. 103, no. 9, 2024, article 104044. https://doi.org/10.1016/j.psj.2024.104044
28. Rahman, Md, et al. “Insights in the Development and Uses of Alternatives to Antibiotic Growth Promoters in Poultry and Swine Production.” Antibiotics, vol. 11, no. 6, 2022, p. 766, https://doi.org/10.3390/antibiotics11060766.
29. Rauw, W.M. et al., “Review: Feed efficiency and metabolic flexibility in livestock”. Animal. Vol. 19 (2025) 101376. https://doi.org/10.1016/j.animal.2024.101376
30. Reda, F. M., et al. “Capsicum Extract Supplementation Modulates Gut Microbiota and Performance in Japanese Quails.” Animal Feed Science and Technology, vol. 265, 2020, p. 114507.
31. Rosca, I., et al. “Capsaicin Induces Osmotic Stress in Gram-negative Pathogens.” Veterinary Sciences, vol. 7, no. 4, 2020, p. 172.
32. Sahin, K., et al. “Dietary Capsicum Extract Reduces Oxidative Stress in Heat-stressed Japanese Quails.” Poultry Science, vol. 95, no. 2, 2016, pp. 231 – 240.
33. Saleh, A. A., et al. “Herbal Extract Mixtures Improve Antioxidant Status and Performance in Broilers.” Poultry Science, vol. 97, no. 11, 2018, pp. 3927 – 3936.
34. Stevanović, Z. D., et al. „Essential oils as feed additives—Future perspectives”. Molecules, 23(7), 2018, pp1717.
35. Suganya, R., et al. “Phytochemicals in Combination with Antibiotics: Antimicrobial Resistance Breakers.” Antibiotics, vol. 11, 2022, p. 123.
36. Zhang, Benyuan et al. “Mitochondrial Stress and Mitokines: Therapeutic Perspectives for the Treatment of Metabolic Diseases.” Diabetes & Metabolism Journal vol. 48,1, 2024, pp. 1-18.
37. Zhan, Ru, et al. “Effects of Antibiotics on Chicken Gut Microbiota: Community Alterations and Pathogen Identification.” Frontiers in Microbiology, vol. 16, 2025, article 1562510. https://doi.org/10.3389/fmicb.2025.1562510
38. Zhang, Y., et al. “Effects of Vanillin, Thymol, and Eugenol on Glucose and Lipid Metabolism via TRPV1 Activation.” Journal of Agricultural and Food Chemistry, vol. 65, no. 13, 2017, pp. 2719 – 2727.

Learning from AGP mechanisms to advance poultry nutrition yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.

Precision nutrition is reshaping commercial poultry production by extending beyond feed formulation into data-driven health and performance management. Advances in sensor technologies, blood biomarkers, and machine learning now enable more accurate, timely nutritional decisions. By integrating multiple data streams, precision nutrition supports improved bird performance, flock uniformity, animal welfare, and long-term sustainability in modern poultry systems.

HAS NUTRITION NOT ALWAYS BEEN PRECISE?
The term ‘precision nutrition’ could suggest that current nutrition practices are ‘imprecise’. However, nutrition has been, and will always remain, a precise science, striking a balance between providing enough nutrients to meet the requirements of the animal for optimal growth, without unnecessarily inflating feed cost or nutrient excretion into the environment.

Production animal nutrition has also been a constantly evolving discipline, with regular adoption of novel concepts e.g. digestible nutrient formulation systems, net energy etc. In the past few years, improved access to sensor technologies, data science tools such as machine learning and artificial intelligence, has accelerated this evolution. Systematic data generation, advanced analytics, and interpretation, offer disruptive opportunities to better understand the nutrition and health status of the flock.

In this new paradigm of animal nutrition, veterinary health, and live production, data is the new currency. Companies that collect, monitor, map, visualize, analyze, and interpret their data will be the most competitive and sustainable. The new tools available to the poultry industry present an opportunity to be more precise.

Figure 1 shows how data are gathered, collected, and interpreted in the Verax™ platform. First, blood samples are taken from birds and analyzed on site. The analysis results are added to the secure Verax™ cloud database via a dedicated app. The results are benchmarked, and the significance of the analysis results are given to the producer who can then make more informed management decisions. Over time, comparisons can be made to previous seasons or flocks, helping to identify changes. Using Verax™ is especially helpful when implementing new flock management changes or nutritional changes, as the data can be used to see how the changes are affecting the physiology of the bird.

ALL IN THE DETAIL
What makes Verax™ so valuable is the systematic and thorough method of data collection, notation, and storage. It is only by having such detailed notes on each sample that disruptive insights are found. The level of detail in Verax™ allows certain biomarkers to be linked with veterinary health outcomes. Any high value phenotype can be plugged into machine learning to produce algorithms for diagnostics and predictive tools.

Verax™ is accessed via a user-friendly and secure app interface on a mobile device. There are already many benefits to digitizing necropsies, but the real value comes from the thorough annotation and standardization of the data capture, allowing more in-depth insights to be drawn from the samples. The consistency of capturing several blood biomarkers and veterinary observations from every animal, house, farm and complex, allows machine learning to alert Verax™ users to potential problems before they develop.

Verax™ is part of a wider precision animal farming platform. Blood biomarkers are only one source of input, but data can be gathered from a whole range of biological matrices including saliva, digesta and excreta contents, feed and water consumption, and genetics (Figure 2).

EXAMPLES OF GETTING CALCIUM AND PHOSPHORUS RIGHT
Calcium (Ca) and phosphorus (P) are the most abundant mineral elements in the body. Most of the body’s Ca and P is stored in the skeleton which is why these minerals are so closely linked to bone health and skeletal integrity. But Ca and P are also involved in several other important pathways such as energy metabolism, blood clotting and neuromuscular function. Insufficient levels or an inadequate ratio of these minerals in the diet can cause several problems such as rickets, tibial dyschondroplasia, lameness, nerve function problems, poor appetite and body weight uniformity.

Total blood Ca is typically around 11.5-12 mg/dL, and P is usually approximately 6-7 mg/dL (Figure 5). Approximately 47-48% of blood Ca is ‘ionized’ (metabolically active; Figure 4), whereas the remainder of blood Ca is covalently bound to plasma proteins or associated with anions such as phosphate or lactate. These concentrations do not substantially change with bird age or gender but can be disrupted by various nutrition and management factors.

For example, ionized Ca has been observed as low as 0.6 mmol/l. Birds with levels of ionized Ca as low as this will display atypical behaviour, nervous paralysis and elevated mortality. More often, subclinical hypocalcemia or hypophosphataemia are observed, which is associated with low body weight (Figure 6) and poor flock uniformity.

Skeletal abnormalities such as bacterial chondronecrosis with osteomyelitis (BCO), enterococcus, and femoral head necrosis, are significantly more prevalent when ionized Ca levels drop below 1.1-1.2 mmol/L or when plasma total Ca concentration is below 10-10.5 mg/dL. Low plasma phosphorus, which is often associated with high plasma Ca, is also associated with skeletal abnormalities but most commonly is related to poor growth rate and body weight uniformity.

ENVIRONMENTAL pH CAN IMPACT Ca LEVELS IN THE BLOOD
Verax™ data has shown an association between the Ca and P status of the bird and season. This may be related to blood pH or a more general disruption to the acid/base balance of birds as ambient carbon dioxide concentrations rise and fall with altered respiratory tract health and ventilation rates. Blood pH is important as this influences the proportion of Ca that is metabolically active. This interplay is one example of why more systematic analysis of multiple data streams can shed light on underlying physiological changes relevant for efficiency and welfare. Further investigation is currently being carried out to assess seasonal variations in data held in the Verax™ platform, with the possibility of making recommendations for different feeding programs in warmer or colder seasons that go beyond the traditional adjustments made by nutritionists.

USING BLOOD BIOMARKERS TO ADJUST FEED FORMULATIONS
Even though Ca levels are hormonally regulated, blood Ca and P does respond to dietary inputs. Parathyroid hormone, calcitonin and vitamin D will regulate blood Ca levels to some extent, but not completely. Figure 6 shows a statistically significant association between dietary Ca and plasma Ca. This has also been shown for P (Figure 7). Interestingly, whilst dietary P has an influence on blood P, diet Ca is capable of influencing both Ca and P. Specifically, over-feeding dietary Ca has a supressing effect on blood P and vice versa. Whilst dietary Ca and P do have some influence on blood Ca and P, blood pH and acid/base balance may be more important in order to optimise blood Ca and P concentrations. For example, the proportion of total blood Ca that is metabolically active and can contribute to skeletal mineralisation is normally around 47-48% in broilers. However, this can drop by 2-4% for every 0.1 unit increase in blood pH. These interactions highlight the importance of monitoring biomarkers beyond blood Ca and P when attempting to optimise the nutrition and health status of the bird.

A common disturbance to optimal blood pH in commercial broilers is high chloride intake. Chlorine based sanitizers and water treatments are not unusual, plus sources of chloride are used in the feed. These can all, inadvertently, push blood pH down which might have negative implications, not only for Ca and P, but for renal health, litter quality and growth rate. Nutritionists need to understand the balance between cations and anions, and use them as levers within the least-cost formulation strategy to produce desirable outcomes.

EARLY DETECTION OF HEALTH PROBLEMS
In 2019, a trial was conducted looking at the response time of certain blood biomarkers to a coccidiosis challenge. Potassium and carotenoids began to shift 3-7 days before any other obvious or macroscopic symptoms becoming apparent. This rapid response sparked the idea for an early warning system for coccidiosis. The hypothesis was proposed that with enough data, machine learning could be used to create a classifier model with a forecasting capacity for coccidiosis.

MACHINE LEARNING
Verax™ uses supervised machine learning to create classifier and regressor models. There are currently many tens of thousands of data points in the database, gathered from commercial broilers with a naturally occurring prevalence of coccidiosis. To create the model, the data set was split into two sections; 60% used for training, and 40% used for validation. All the birds with coccidiosis were identified and a biomarker profile was created which predicted that phenotype. The model was then validated on the other subset of birds. Over time and with more data, especially from birds that have coccidiosis, the accuracy of the model increases and permits the identification of specific Eimeira species.

This principle was applied in practice on a farm in the US. Blood samples were taken from birds on four different farms on day 14. The blood analysis results were used to predict that two of the farms would have a coccidiosis outbreak later, and the other two would not. A second visit to the farms on day 28 confirmed the predictions.

Although the model is not 100% accurate yet, there is a very strong association with excellent statistical performance in terms of false positive and false negative rates on the forecasting ability of the model. Figure 8 shows an example of the user interface in Verax™ for tracking flocks, including coccidiosis scores, over time.

CONCLUSIONS
• The importance of data cannot be overstated. Data science will continue to unlock new opportunities for poultry producers if a more systematic approach is taken towards data handling, capturing, and processing.
• New technologies and tools are allowing nutrition to be more precise than ever before. Nutritional optimization is getting easier with improved monitoring and shorter feedback loops.
• By collecting and analyzing data from a variety of sources, nutritionists are better able to unlock new levels of bird performance. New tools like large language models are making it much easier to ingest unstructured data sources, but the data must be accessible to begin with.
• Blood biomarkers can be used to predict disease outbreaks earlier than ever before.

About Dr. Markus Wiltafsky-Martin
As Director of Service Commercialization in Evonik’s Animal Nutrition business, Dr. Markus Wiltafsky-Martin received his degree in Agricultural Science from the Technical University of Munich, Germany. He has been with Evonik since 2009 and has more than 16 years of experience in conducting projects with stakeholders of the animal protein business, focusing on the importance of feed ingredient quality for the overall business. In the last 13 years, Wiltafsky-Martin has worked intensively on the quality evaluation of feed ingredients and on the translation of analytical data into valuable information for the feed industry via advanced data evaluation.

Precision nutrition in commercial poultry production yazısı ilk önce Feed & Additive Magazine üzerinde ortaya çıktı.