Isoleucine Enhanced the Function of the Small Intestinal Mucosal Barrier in Weaned Piglets to Alleviate Rotavirus Infection

Abstract

Background: Rotavirus (RV) is a major cause of diarrhea in young children and animals, especially piglets, leading to substantial economic losses in the global pig industry. Isoleucine (Ile), a branched-chain amino acid, plays an important role in regulating nutrient metabolism and has been shown to improve diarrhea. This study aimed to evaluate the effects of Ile supplementation on the mucosal immune barrier of the small intestine in RV-infected weaned piglets. Methods: Forty-eight 21-day-old weaned piglets were randomly divided into three dietary treatments (each treatment was subdivided into two groups, eight replicates per group), with 0%, 0.5%, or 1% Ile added for 15 days, and then, one group from each treatment was challenged with RV. Results: The results showed that 1% Ile added to the diet promoted the healthy development of the intestinal mucosa. Ile could restore the reduced villus height in the ileum and the goblet cell number in the duodenum and ileum to normal levels, improving the intestinal epithelial tight junctions in RV-infected piglets. Additionally, Ile increased the activity of lipase, amylase, and sucrase, as well as superoxide dismutase (SOD) and glutathione (GSH), along with the expression of SIgA, DEFβ1, and DEFβ2 in parts of the small intestine. Conclusions: The addition of Ile to the diet mitigated the effects of RV infection on intestinal morphology and mucosal barrier function, as well as the physiological functions of weaned piglets, and improved the antioxidant and immune functions of the piglets to some extent. These findings offer valuable insights, contributing to a deeper understanding of the role of Ile in supporting intestinal health.