By Casey Zangaro
Soybean meal is the primary protein source in pig diets due to their consistent supply and advantageous amino acid profile. Recognizing its quality is essential for swine nutritionists, as anti-nutritional factors, such as trypsin inhibitors, can affect pig performance, according to Liener, 1994.
What are trypsin inhibitors and why are they important?
Trypsin inhibitors are natural compounds found in raw soybeans that block digestive enzymes, mainly trypsin and chymotrypsin. These enzymes are essential for proper protein digestion in pigs. Elevated trypsin inhibitor activity (TIA) decreases protein digestibility and amino acid absorption.
Commercial soybean meals are heat-processed to reduce trypsin inhibitor activity to safe levels. Proper heating inactivates most trypsin inhibitors without affecting amino acid availability. Underheating can increase TIA, whereas overcooking may reduce amino acid digestibility, particularly lysine.
Diets containing inadequately processed soybean products have been shown to reduce protein digestibility, slow growth and decrease feed efficiency. Monitoring soybean meal quality using indicators such as trypsin inhibitor activity, urease activity and protein solubility can help nutritionists and producers ensure that heat processing has adequately inactivated inhibitors and that pigs receive the full nutritional benefit of the diet. The effects of trypsin inhibitors are most pronounced in young pigs whose digestive systems are still developing, but older pigs may also be affected if TIA levels are excessive.
Source : msu.edu