International Symposium Showcases the Future of Poultry Nutrition Through Net Energy, Modeling, and Precision Feeding

Edgar O. Oviedo-Rondon¹, Nilva K. Sakomura², and Rony Riveros Lizana²

¹Prestage Department of Poultry Science, North Carolina State University
²Department of Animal Science, Faculty of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal Campus, São Paulo, Brazil

Scientists, nutritionists, industry leaders, and graduate researchers from around the world gathered at São Paulo State University (UNESP) in Jaboticabal, Brazil, on June 2 and 3 for the International Symposium on Nutritional Modeling and Energy Metabolism in Poultry Nutrition, a meeting that highlighted the growing role of mathematical modeling and net energy (NE) systems in shaping the future of poultry nutrition.

Organized by Professors Nilva Sakomura, Marcos Macari, and Rony Riveros, the symposium reflected more than 25 years of research conducted at UNESP’s Laboratory of Poultry Science (Lavinesp) coordinated by professor Sakomura.

Supported by multiple thematic grants from the São Paulo Research Foundation (FAPESP), this long-term research program has focused on developing practical tools for implementing NE systems in commercial poultry production.

Beyond presenting scientific results, the meeting sought to bridge the gap between research and industry by fostering collaboration among universities, nutrition companies, and poultry producers.

A New Era in Poultry Nutrition

A central theme throughout the symposium was that poultry nutrition is entering a new phase in which precision replaces generalized recommendations. For decades, feed formulation has relied on apparent metabolizable energy (AME) and nitrogen-corrected metabolizable energy (AMEn).

Researchers proposed NE as a more accurate alternative because it accounts not only for ME but also for the heat generated during nutrient metabolism.

According to several speakers, adopting NE-based formulation could improve feed efficiency, reduce production costs, and enhance environmental sustainability.

Although these systems have supported remarkable gains in productivity, speakers argued that they no longer fully reflect the biological efficiency of modern poultry genetics or the increasingly diverse range of feed ingredients used worldwide that differ from traditional corn-soybean meal diets.

New Equations Improve Energy Evaluation for Broilers

One of the Symposium’s principal scientific contributions was the presentation of predictive equations for estimating NE in poultry feed ingredients and coefficients of utilization.

Researchers evaluated 48 ingredients that varied widely in nutrient composition, combining conventional metabolic trials to determine ME with indirect calorimetry to quantify oxygen consumption and carbon dioxide production and to calculate the heat increment.

The findings confirmed that approximately one-quarter of metabolizable energy is lost as heat during nutrient utilization, demonstrating that ME consistently overestimates the energy available for productive functions.

Statistical analyses identified crude protein (CP) and dietary fat as the primary determinants of these energy losses.

Table 1. Corn Products Feed Data. Nutritional Composition & Energy Values of Corn Derived Feedstuffs

Table 2. Soybean Products Feed Data. Nutritional Composition & Energy Values of Soybean Derived Feedstuffs

The resulting prediction equations performed well when validated against independent datasets, suggesting that they can accurately estimate NE for both complete diets and individual feed ingredients to feed broilers.

For complete diets, the best equation evaluated was:

For individual ingredients, the equation

Such equations offer nutritionists practical alternatives to labor-intensive calorimetry studies when evaluating new ingredients.

Precision Feeding for Modern Layers

Commercial laying hens also received considerable attention. Researchers described studies using experimental diets designed to generate wide variation in nutrient composition while:

• Measuring heat production
• Maintenance requirements
• Body energy retention
• Egg energy deposition through respiratory calorimetry

These data supported the development of practical equations that predict NE using ME, CP, and ether extract:

More importantly, the research demonstrated that ingredients with similar ME values may differ substantially in biological efficiency.

Certain corn hybrids with low CP content (6.92% CP) converted dietary energy more efficiently than higher-protein or high-lysine varieties.

At the same time, soybean meals varied in energetic value despite similar chemical composition.

But 45% CP soybean meal was 1.22% less efficient than 46% CP soybean meal.

These findings suggest that future ingredient evaluation should emphasize nutrient utilization (NE/ME ratio) rather than relying exclusively on conventional chemical analyses.

Another impact of NE-based formulation is that it promotes dietary CP reduction, since excess protein is energetically penalized.

Models Become Practical Tools

Beyond individual equations, several speakers highlighted the broader value of mathematical modeling as a decision-support tool.

Rather than replacing empirical nutrition based on tables, these models integrate information on:

• Genetics
• Age
• Environmental conditions
• Ingredient variability
• Health status
• Production objectives to generate more precise feeding recommendation

Such models enable nutritionists to simulate multiple formulation scenarios before feed manufacture, improving precision while reducing unnecessary nutrient oversupply.

Factorial Models for Broilers and Broiler Breeders

A couple of presentations addressed the development of NE factorial models that describe the dynamics of energy partitioning in broilers and broiler breeders.

To estimate the energy needs of broilers, the NE for maintenance, growth, and physical activity was considered, with flock stocking density and environmental temperature influencing the NE for maintenance.

Additionally, it was demonstrated that the efficiency of fat and protein deposition in the body varies with environmental temperature, and the corresponding utilization coefficients were presented.

The NE for maintenance of broiler breeders between 29 and 65 weeks was determined to be 259 KJ/kg^0.75*d.

However, the efficiency of nutrient deposition or reserve mobilization was affected by energy intake and age.

The model evaluated for:

Future studies in this area should include the effect of ambient temperature, degree of feathering, and physical activity in this model.

One of the presentations discussed the new LAVINESP NE Model to determine broiler and layer needs for NE according to genetic potential for protein deposition, temperature, air velocity, and stocking density.

Another discussion was made on models to predict calcium and phosphorus utilization and the effects of phytase. Finally, the Broiler Growth Model (BGM) was described as a mechanistic, web-based tool to connect growth theory with practical decision-making through simulations of multiple nutritional and environmental combinations.

The BGM and the Egg Production Model can be accessed at www.poultrymodel.com.

In this portal users can simulate distinct environmental and nutritional conditions. Additionally, there are tools to develop nutritional programs for broilers, pullets, and laying hens.

Feed Processing Also Matters

Researchers also demonstrated that nutrient utilization depends not only on ingredient composition but also on feed processing.

Enzymes like phytase:

Improve nutrient availability and reduce heat increment, thereby increasing energy utilization, as evidenced in the NE system.

Likewise, optimized feed processing enhances digestibility while reducing the maintenance energy required for digestion.

Together, these factors reinforce the importance of evaluating how nutrients are delivered as well as their chemical composition.

Industry Looks Toward Implementation

Representatives from breeding companies, feed additive manufacturers, and nutrition companies complemented the scientific program by discussing the practical implementation of NE systems.

They compared values obtained by diverse research groups that have developed equations to predict NE but noted a lack of clarity about optimal NE levels.

Precision Nutrition Supports Sustainability

Although nutrition remained the symposium’s primary focus, environmental sustainability emerged as a consistent theme.

Improved nutritional precision not only enhances economic performance by almost 17% but also reduces nutrient losses and environmental impacts.

Because protein metabolism generates considerable heat, NE-based diets often achieve better efficiency of energy utilization with lower CP (0.79) concentrations supplemented by crystalline amino acids than standard CP diets (0.76). This strategy improves nitrogen utilization while reducing nitrogen excretion.

Similarly, more accurate energy evaluation facilitates greater use of alternative ingredients and agricultural by-products, decreasing dependence on traditional feedstuffs such as corn and soybean meal.

Collectively, these approaches contribute to more efficient and environmentally responsible poultry production.

Looking Ahead

The symposium concluded with a clear message: poultry nutrition is evolving from an empirical discipline toward a predictive science driven by physiology, mathematics, and computational modeling.

Rather than replacing established nutritional principles, biological modeling and the NE approach refine them by providing a more biologically meaningful assessment of nutrient and energy utilization.

Nevertheless, there was a broad consensus that the industry is approaching the point at which the advantages of NE systems outweigh the challenges of transitioning from conventional ME-based formulations.

In biological modeling, it was concluded that model implementation depends on trained personnel to understand the values and boundaries that each model may have to support decision-making in line with the goals.

The use of automated data collection, electronic sensors, farm connectivity, and artificial intelligence may help to improve the quality, accuracy, and speed of predictions made by biological models.

For nutritionists, researchers, and poultry producers, the implication is clear: the next generation of feed formulation will be defined not simply by the nutrient composition of ingredients, but by how efficiently birds convert those nutrients into meat and eggs.

International Cooperation Drives Progress

The symposium reflected the increasingly global nature of poultry nutrition research. Scientists from Brazil, France, Canada, Australia, and the United States contributed expertise in physiology, nutrition, genetics, mathematical modeling, and feed formulation.

Long-standing collaborations among UNESP, INRAE, Université Laval, the University of Sydney, the University of New England, and participation of Cobb-Vantress, Adisseo, Trouw Nutrition, and numerous graduate researchers have created a strong international network supporting continued innovation in poultry nutrition to accelerate the transfer of research into commercial practice.

Further Information

For more information you can access the entire Proceedings of this event:

Macari, M., Riveros, R. & Sakomura, N. (2026). Proceeding of Nutritional Modeling and Energy Metabolism in Poultry Nutrition. Proceeding of Nutritional Modeling and Energy Metabolism in Poultry Nutrition, 1–135.

DOI: https://doi.org/10.5281/zenodo.20747168