Maternal dietary inulin intake during late gestation and lactation ameliorates intestinal oxidative stress in piglets with the involvements of gut microbiota and bile acids metabolism.

Maternal inulin intake has been shown to alleviate oxidative stress in piglets, but the role of bile acids (BAs) in this process remains unknown. This study aimed to investigate the roles of gut microbiota and BAs metabolism in the amelioration of intestinal oxidative stress in piglets through a maternal inulin diet. A total of 40 sows were allocated into two dietary treatments from day 85 of gestation until the end of lactation: CON (control diet) and INU (diet with 2% wheat bran replaced by inulin). An oxidative model was further established on the intestinal porcine epithelial cell-jejunum 2 cell line (IPEC-J2) to examine the effect of bacterial BAs on intestinal oxidative stress. Results showed that the maternal inulin diet promoted the average daily gain of piglets during suckling and reduced diarrhea rate during weaning (P = 0.026 and P = 0.005, respectively). Piglets from the INU group had lower serum levels of reactive oxygen species (P = 0.021), malondialdehyde (P = 0.045), along with higher serum levels of glutathione peroxidase (P = 0.027), catalase (P = 0.043), and total superoxide dismutase (P = 0.097). Compared to the CON group, maternal inulin intake increased fecal ursodeoxycholic acid (UDCA) by 10.84%, hyodeoxycholic acid (HDCA) by 250.64% (P = 0.026), and lithocholic acid (LCA) by 16.41% (P = 0.048) in piglets. Moreover, the fecal abundance of Ruminococcus and Christensenellaceae_R-7_group increased by 167.08% and 75.47% in INU piglets (P = 0.046 and P = 0.037, respectively). Furthermore, the in vitro study using IPEC-J2 cells demonstrated that UDCA, LCA, and HDCA attenuated intestinal oxidative stress by mediating kelch-1ike ECH-associated protein 1/nuclear factor E2-related factor 2 signaling. In conclusion, our results suggested that maternal dietary inulin intake during late gestation and lactation alleviates intestinal oxidative stress of piglets by regulating gut microbiota and BA metabolism.