Soy-based ingredients can harbor high levels of trypsin inhibitor protein (analytically expressed by activity: TIU) due to inherent variability and inconsistent processing. Feeding pigs diets high in TIU has been shown to reduce pig growth performance by way of decreasing ileal nitrogen digestibility. Additionally, previous research has demonstrated a potential link between hindgut protein fermentation and pig morbidity. Therefore, our objective was to assess the interaction between dietary TIU concentration (TIU/mg) and F18 enterotoxigenic E. coli (ETEC) infection in nursery pigs. In this study, pigs fed diets at or above 2.4 TIU/mg experienced higher antibiotic usage and mortality rates under ETEC challenge, while those fed 4.2 TIU/mg observed impaired growth performance. Interestingly, dietary TIU concentration did not influence mucosal ETEC attachment measured by in situ hybridization or colonic fermentation based on bioamine and volatile fatty acid concentrations in challenged pigs. Altogether, feeding nursery pigs diets high in TIU will negatively affect pig growth performance and may exacerbate ETEC-associated morbidity and mortality.

Read the full article in the Journal of Animal Science.