New Research Highlights Hidden Risks of Trypsin Inhibitors in Soybean Meal

White paper reveals how widespread variability in soybean meal quality affects swine performance.

Soybean meal continues to be one of the most important protein sources in swine and poultry diets around the world. But while its role in feed formulations is well established, new research suggests that not all soybean meal is created equal—and the hidden variability in soybean quality may be affecting animal performance more than many producers realize.

A newly released white paper from NOVUS draws on more than a decade of global data to show why trypsin inhibitor (TI) levels in soybean meal remain a persistent challenge for nutritionists and livestock operations. The paper highlights how TI—an anti-nutritional factor naturally found in soybeans—can reduce amino acid digestibility, hinder growth, and hurt overall feed efficiency.

“Soybean meal is the greatest protein contributor in most diets, yet its nutritional value is often assumed rather than measured,” explains Rasha Qudsieh, NOVUS global enzymes and microbials senior manager.

“Our data from more than 1,900 soybean meal samples globally shows that trypsin inhibitor levels are highly variable across regions, years, and processing methods, and even small increases in TI can negatively impact amino acid digestibility, feed efficiency, and animal performance.”

TI Levels Persist Even in Commercially Processed Soybean Meal
Trypsin inhibitors occur naturally in soybeans as part of the plant’s defense system. While TI is often associated with under-processed soy products, NOVUS research indicates the issue is more widespread.

According to their global dataset, measurable TI levels persist even in commercially processed soybean meal, with documented effects on gut health and growth across poultry and swine species.

These TI levels interfere with protein digestion by blocking trypsin, a key digestive enzyme, forcing animals to expend additional energy producing more enzymes and reducing the overall efficiency of feed utilization.

“We’ve analyzed hundreds of soybean meal samples globally, creating an extensive database on trypsin inhibitors,” says Paula Fisher, NOVUS analytical services senior manager.

“We’ve also invested years developing practical methods to measure TI accurately. This paper shares what we’ve learned and explains why routinely monitoring TI is becoming increasingly important for nutritionists who want consistency in animal performance and predictability in their financial returns.”

Key Insights From the White Paper
The white paper, titled Outsmarting Trypsin Inhibitors, outlines several findings that challenge traditional assumptions in feed formulation:

1. There is no universally “safe” TI level -- Even moderate increases can negatively affect digestibility and animal performance, especially in younger or high-performing animals.
2. TI levels vary widely by region, crop year, and processing method --  This variability makes relying on standard book values increasingly unreliable.
3. Heat processing alone does not guarantee low TI  -- Over- or under-processing can both lead to issues, and even properly processed soybean meal may contain residual TI.
4. TI impacts both swine and poultry -- Documented effects include reduced growth, poorer feed efficiency, and digestive stress.
5. Measuring and managing TI is now a practical reality

With improved analytical tools and expanding databases, routine monitoring is becoming more accessible for feed mills and nutritionists.

A Living Database for the Global Feed Industry
NOVUS says it plans to update the white paper annually based on new findings from its Global Trypsin Inhibitor Database, providing the livestock industry with ongoing insights into soybean meal quality trends and their implications for animal nutrition.

The white paper is available at: novusint.com/resources.