These findings suggest that IUGR could decrease small intestinal morphology and function, whereas dietary BA supplementation could promote the ileum development of NBW piglets, protect the liver by reducing plasma ALT and AST levels, and increase the proportion of potentially beneficial bacteria in the small intestine of NBW and IUGR piglets, contributing to intestinal development and health of weaned piglets. The gene discussed is GPT; the disease is fetal growth restriction.