Poultry Feed Additives and the impact of Protease

Jun 28, 2024 Animal Nutrition & Health

According to the United Nations, the global population will be 8 billion near the end of 2022 and will rise to 9.7 billion by 2050. This rapid growth demands an increase in the speed, efficiency and quantity of worldwide food production, all without unreasonable contributions to environmental concerns like climate change.

While there are many ways to accomplish this, one factor of particular interest is the addition of animal feed additives to the diets of poultry, pigs and other domestic animals. As these additives are rapidly adopted in the industry, it becomes increasingly important to study their impact on animal growth, gut health, environmental impact and more.

We will explore one such animal feed additive — protease in the diets of poultry in this article, reviewing recent research to clarify its utilization.

History of Poultry Enzyme Feed Additives

As with many elements of the poultry industry, animal feed additives are at the center of an ongoing conversation. To fully understand its role of improving feed efficiency, it is firstly necessary to understand how they originally became accepted in animal nutrition.


Inclusions of non-starch polysaccharide (NSP)-degrading enzymes, β-glucanase and xylanase, became a routine procedure in the 1990s. These enzymes were added to the traditional poultry diets based on viscous grains, including barley and wheat. The goal of these additives were to increase feed efficiency, allowing animals to obtain more energy from high-fiber diets. According to the research by the University of Minnesota, the enzymes delivered results: Reports indicate that animal growth performance, nutrient digestibility and immune responses were all improved. Motivated by these positive outcomes, the food production industry spent the next decade accepting similar additives in the form of phytate-degrading feed enzymes, or phytases. Presently, almost every wheat-based broiler chicken diets contain both phytase and xylanase.


Development of feed additives as an animal health and growth promoter did not stop there, however. Other enzymes, including exogenous proteases, have been developed to improve poultry production, including digestibility, broiler growth and gut health. This consistent development indicates that the poultry industry has accepted feed additives as one of many solutions to a growing demand for human nutrition — and that animal science and ongoing research have an important part to play in the decisions made by farm service managers, food technologists and other poultry nutrition experts. Today, research is being conducted to find out exactly how effective various additives are and how they can play an even greater role in the global economy. This suggests an ongoing evolution — one that may change the way food producers look at the challenges and goals associated with meeting worldwide food demands.

The Goals of Poultry Feed Additives

As the needs of poultry meat organizations become more complex and consumer demand continues to rise, the goals characterizing feed additives must evolve to keep up. Analyzing these objectives is key to appreciating the value of VTR protease and similar feed ingredient additives.

Here are just a few of the most significant needs driving the development of chicken feed solutions:

1. Optimizing Dietary Energy

According to a worldwide research team, dietary energy is the largest cost consideration in poultry operations. As such, it is important for animal nutrition decision-makers to identify the ideal protein-to-energy ratio, which is a key element in cost-effective but optimized broiler growth and performance. Many poultry feed additives seek to optimize this ratio in the existing wheat-based broiler diets.

2. Improving Digestibility

Many poultry feed additives, especially exogenous proteases, are designed to augment the activities of the chicken’s natural gut enzymes, including pepsin and trypsin. This facilitates the improved digestibility of dietary proteins and increases the intestinal uptake of amino acids.

3. Controlling Feed Costs

Although a high-protein poultry diet can be expensive, especially one based on soybean meal, improved digestibility indicates better nutrition from the same amount of feed intake. This allows poultry production organizations to operate more efficiently while still meeting increased consumer demand.

4. Improving Broiler Meat Quality

Elements like broiler growth performance and feed intake ultimately impact meat quality, which can be measured based on several factors:

  • Carcass weight.
  • Dressing percentage.
  • pH value of carcass elements.
  • Muscle coloration.
  • Protein, fat and water content.


To optimize performance in these and other areas of meat quality, many feed additives are designed to increase feed intake, nutrient digestibility, broiler growth and more.

5. Reducing Environmental Impact

According to the research by Cambridge University, poultry production may be more environmentally friendly than the production of other animal operations. However, it still contributes to issues including eutrophication and acidification; For example, feed production and transport represents about 70% of the global warming potential of poultry production, while manure management contributes between 40% and 60%.

To reduce environmental impact, the Cambridge study identifies a solution: improving feed efficiency. This is increasingly achieved through the utilization of poultry feed additives, which increase nutrient digestibility and decrease the amount of undigested feed content lost via waste.

6. Reducing the Risk of Necrotic Enteritis

When undigested protein escapes into the hindgut of a broiler, bacterial growth can result including Clostridium perfringens, the causative pathogens Necrotic Enteritis (NE). By causing reduced food intake, weight gain and other broiler performance issues, NE has created $6 billion in losses per year across the global poultry industry, according to poultry science research from universities in the United States.

Poultry feed additives are often included in chicken diets to reduce the risk of necrotic enteritis (NE). When nutrient digestibility is increased, less undigested protein is left to escape into the hindgut. This protects both meat performance and overall cost for producers.

Study of VTR Biotech Protease in Broiler

A study was conducted in 2021 to evaluate the efficacy of exogenous protease in wheat-soybean meal based-diets in broiler chickens from 1 to 35 days post-hatch housed on ‘deep litter’ or conditions similar to the commercial Australian situation.


Study Design

The experimental design contained three dietary treatments including a positive industry standard diet (PC), negative control diet (NC) with reduced amino acid densities and NC diet supplemented with VTR protease. All diets were supplemented VTR phytase at 1000 FTU/kg to be consistent with standard industry practice.

A total of 360 one day-old off-sex male Ross 308 birds (parent line) were radomly assigned to 24 floor pens with 15 birds per pen and each treatment had 8 replicates. Pens were located in an enviromentally-controlled deep litter facility on the Camden Campus of the University of Sydney.On day 23, 5 birds selected randomly from each pen were sacrificed to collect ileal digesta to detemine protein and amino acid digestibility coefficients.



When the study was complete, researchers grouped results into two different categories:


Growth Performance

The overall performance of birds offered the positive control diet in the study outperformed 2021 Aviagen performance objectives for weight gain by 9.7 % and FCR by 3% from 1 to 35 days post-hatch.

Overall, from 1-35 days post-hatch, reducing amino acid density in the NC diet compromised weight gain by 5.0% (2644 versus 2513 g/bird, P = 0.018) and increased FCR by 5.1% (1.363 versus 1.432 g/g, P = 0.005). Application of protease generated 70g/bird increase in BWG and 0.024 g/g decrease in FCR (P > 0.05) from 1-35 days post-hatch. There was no dietary effect on mortality rate (P = 0.507)


Nutrient Digestibility

Supplementation of protease significantly increased dry matter digestibilties (P<0.01) by 6.9% over NC diet. Desipte being non-signitifcant, broiler chickens offered the NC diet had lower apparent amino acid digestbilities in comparison to the PC diet and supplementation of protease numerically increased apparent digetsbilities of all 16 tested amino acids.

Numerially, VTR Biotech protease supplementation improved crude protein digestibility by 3.92% over NC diet, while tyrosine digestibility improved by 5.88%. Other nutrient digestibility improvements included:

  • Methionine: 1.84%
  • Valine: 3.23%
  • Proline: 2.05%
  • Arginine: 2.40%
  • Histidine: 2.38%
  • Threonine: 3.40%
  • Glutamic acid: 1.37%
  • Glycine: 3.36%
  • Serine: 3.05%



VTR protease showed noteworthy improvements in both broiler performance and nutrient digestibility.

However, this is not the only topic of interest surrounding VTR protease and other poultry feed additives. Researchers indicated that the combination of phytase and protease could further improve nutrient digestibility due to the beneficial interaction between these two enzymes. As such, researchers recommended that more studies be conducted to investigate this potentially valuable relationship.

In summary, VTR protease lived up to the promises made by early animal feed additives and, in many ways, surpassed them. This is just one example of how continued research, development and industry conversation can lead to innovative advancements in feeding habits.

Key Takeaways: Impact of VTR Protease on Poultry Performance

Although much of the research data speaks for itself, there is value to be had in taking a closer look at key takeaways. Consider the elements that stand out from this study and the surrounding global conversation:

  • VTR protease leads to multiple benefits. This poultry feed additive improves the nutrient digestibility of protein, tyrosine, methionine and more, indicating that it can influence broiler health and performance in more ways than one.
  • Poultry feed additives are promising. Although there may be other ways to address the demands of a fast-growing world population, this study has proven that feed additives like VTR protease deserve significant consideration and should not be overlooked by any organization involved in poultry production.
  • Feed additives can benefit other industries. Poultry physiology is unique and the results of this study cannot necessarily be applied to any other livestock; however, research by experts across the animal science industry indicates that VTR protease may have similarly positive effects on gut health, feed intake, nutrient digestibility and growth in other livestock like pigs.
  • There is more research to be done. VTR protease is already creating positive results. Nutritionists and feed additive researchers can learn from the success of VTR protease, conducting more studies to identify the ways in which this product can combine with various poultry feed types and achieve improved results.


These takeaways are particularly relevant because they inform the decision-making process for many animal nutrition experts. Feed additives like VTR protease are a somewhat new variable in the discussion surrounding chicken nutrition, feed efficiency and solutions for environmentally friendly meat production; as such, poultry operations should turn to reliable research when creating a broiler diet. This is especially true as not all animal feed additives can necessarily deliver the results or reliability of VTR protease.

Learn More About Animal Feed Additives

As the world population continues to grow, it is more important than ever for livestock producers to find safe, sustainable, efficient ways of improving their yield without compromising quality or the environment. To address this issue, animal science must take a leading role in the conversations surrounding food production.

Animal feed additives are a perfect example of this approach. With the right research and a long list of impressive results, producers can feel confident adopting new solutions such as VTR protease in poultry feed. This feed additive creates value for the consumer, the company and even the chicken, helping create a stronger, healthier food production system across the globe.

However, even VTR Biotech protease does not represent the end of additive development. Researchers will continue studying new applications and enzyme combinations, learning how VTR protease can act as an example for other innovations in the poultry industry and beyond.




To learn more about animal feed additives like VTR protease, please contact us at: [email protected]