Dietary supplementation with Lactobacillus plantarum modified gut microbiota, bile acid profile and glucose homeostasis in weaning piglets.

: Bile acids (BA) have emerged as signaling molecules regulating intestinal physiology. The importance of intestinal microbiota in production of secondary BA, e.g. lithocholic acid (LCA) which impairs enterocyte proliferation and permeability, triggered us to determine the effects of oral probiotics on intestinal BA metabolism. Piglets were weaned at 28 days of age and allocated into control (CON, n=14) or probiotic (PRO, n=14) group fed 50 mg of Lactobacillusplantarum daily, and gut microbiota and BA profile were determined. To test the potential interaction of LCA with bacteria endotoxins in inducing damage of enterocytes, IPEC-J2 cells were treated with LCA, lipopolysaccharide (LPS), and LCA+LPS, respectively, and expressions of genes related to inflammation, antioxidant capacity and nutrient transport were determined. Compared with the CON group, the PRO group showed lower total LCA level in ileum and higher relative abundance of Lactobacillus genera in feces. In contrast, the relative abundances of Bacteroides, Clostridium_sensu_stricto_1, Parabacteroides and Ruminococcus_1, important bacteria genera in BA biotransformation, were all lower in PRO than in CON group. Moreover, PRO piglets had lower postprandial glucagon like peptide (GLP)-1 level while higher glucose level than CON piglets. Co-administration of LPS and LCA led to down-regulated expression of glucose and peptide transporter genes in IPEC-J2 cells. Altogether, oral Lactobacillusplantarum altered BA profile probably by modulating relative abundances of gut microbial genera that play key roles in BA metabolism, and might consequently impact glucose homeostasis. The detrimental effect of LCA on nutrient transport in enterocytes might be aggravated under LPS challenge.