This study aimed to investigate the effects of pterostilbene (PTE) on the intestinal barrier function, antioxidant capacity, lipid metabolism, and microbial and metabolite homeostasis of suckling piglets via its action on breast milk. Findings indicate that PTE supplementation enhanced the antioxidant status of mature milk and strengthened intestinal barrier function in piglets. Specifically, PTE enhanced intestinal antioxidant status and fatty acid β-oxidation in piglets by regulating the PI3K-