Soybean meal (SBM) is the most important source of dietary protein in many world areas, providing amino acids for poultry and swine. Trypsin inhibitor (TI) is one of the most relevant anti-nutritional factors in SBM. Knowledge of SBM TI contents is critical to maintain optimal performance and health of poultry and swine. To gain knowledge of TI contents in SBM, 434 SBM samples from 12 customers located in different world areas were analyzed for TI by near-infrared (NIR) spectroscopy technology from Jan. 2023 to Jan. 2024. Wet chemistry TI values analyzed by the AOCS Official Method Ba 12a-2020 was used to establish NIR prediction equations. For 9 customers, their NIR instruments, Bruker or FOSS, were calibrated by Novus and they scanned SBM samples (n=315) and sent spectrum to Novus, and Novus analyzed their spectrum for TI content with calibrations specific to each customer. For 3 customers, they shipped their SBM physical samples (n=119) to Novus for analysis of TI by NIR. Among the 434 samples, 343 are solvent extract SBM, 59 are expeller SBM, and 32 are full-fat SBM. Due to unequal sample size and variance, data were subject to Welch ANOVA to evaluate TI content as affect by SBM type, SBM type by world area, and customer; means were separated by Tukey Cramer test with a significant level of 0.05. Across world areas, full-fat SBM had higher TI than expeller SBM, and expeller SBM had higher TI than solvent extract SBM (17.7, 10.8, and 5.1 mg/g trypsin inhibited for full-fat, expeller, and solvent extract SBM respectively). Examination of SBM type by world area revealed that full-fat SBM from North America (17.4 mg/g) and Latin America (17.9 mg/g) had similar TI content, expeller SBM TI content from Latin America (16.8 mg/g) were higher than (P<0.05) those from North America (10.7 mg/g) or North Africa (9.2 mg/g), solvent extract SBM were similar for Asia (6.5 mg/g), North America (6.1 mg/g) and Latin America (5.5 mg/g), which were higher than (P<0.05) those from North Africa (3.2 mg/g). Trypsin inhibitor content of solvent extract SBM varied significantly among customers with the highest averaging 6.5 mg/mg and the lowest averaging 2.7 mg/g. Previous research has indicated that dietary TI content greater than 1 mg/g may cause potential AA digestibility and performance issues, corresponding to 20%, 10%, and 7% SBM inclusion in the diets for TI at 5, 10, and 15 mg/g respectively.
The study indicated there is a need to monitor SBM TI content with NIR to manage variation in SBM quality through supplier selection, formulation adjustment or protease supplementation, achieving precision feeding and improving animal performance and production efficiency.