Gut Microbiota-Derived Ursodeoxycholic Acid Mediates the Resistance to Colonic Inflammation in Pigs.

Microbes in the gut are crucial for host health, yet their role in disease resistance remains unclear. Using fecal microbiota transplantation from disease-resistant Min pigs to Duroc × Landrace × Yorkshire (DLY) pigs, combined with 16S rRNA sequencing and metabolomics, we investigated this relationship. The transferred microbiota alleviated lipopolysaccharide-induced intestinal inflammation and barrier damage in the DLY piglets. Key bacterial genera and bile acid metabolites have been identified, with in vitro evidence showing that the gut microbiome can convert bile acids to secondary forms, primarily ursodeoxycholic acid (UDCA). Subsequent mechanistic validation in a mouse model demonstrated that UDCA acts via the gut-liver axis on the farnesoid X receptor, inhibiting PI3K/AKT/NF-κB pathways and reducing inflammatory responses, thereby preserving tissue structure in the liver and colon. These findings establish a causal link between gut microbiota and disease resistance, indicating that targeting microbial bile acid metabolism may restore intestinal and hepatic health.