Dietary Supplementation with Bacillus subtilis DSM 32315 Alters the Intestinal Microbiota and Metabolites in Weaned Piglets

Sixty-four piglets were allocated to two groups (control and BS), each group including eight replicates with four piglets. Dietary BS DSM 32315 increased (P < 0.05) the abundances of jejunal Leucobacter and Cupriavidus, ileal Thermus, Coprococcus, and Bifidobacterium, as well as colonic Succiniclasticum; and increased the concentrations of ileal straight-chain fatty acids, colonic propionate, branched-chain fatty acids (BCFAs), and tyramine, but decreased (P < 0.05) the colonic indole concentration. The ileal and colonic microbial community structure tended to cluster into two groups. LEfSe analysis identified five microbial biomarkers in jejunum and eight biomarkers in ileum in the BS group, and three biomarkers in colon in the control group. The ileal Bifidobacterium abundance was positively correlated (P < 0.05) with isovalerate concentration, while the colonic Actinobacteria and Lactobacillus abundances were negatively correlated (P < 0.05) with indole concentration.