Dietary supplementation with Bacillus mixture promotes the gut health of weaned piglets

Abstract This study was conducted to investigate the effects of dietary supplementation with a mixture of Bacillus on the intestinal health of weaned piglets. We randomly assigned 120 piglets to three groups; a control group (basal diet), a probiotics group (supplemented with 4 × 109 CFU/g Bacillus licheniformis-B. subtilis mixture; BLS mix), and an antibiotics group (supplemented with 0.04 kg/t virginiamycin, 0.2 kg/t colistin, and 3000 mg/kg zinc oxide). All groups had five replicates with eight piglets per replicate. On days 7, 21, and 42 of the trial, intestine and digesta samples were collected to determine the intestinal morphology, gut microbiota and metabolites, and the expression of genes related to gut health. The results showed that the BLS mix decreased the jejunum crypt depth, increased the ileum villus height, and increased the jejunum and ileum villus height to crypt depth ratio. The BLS mix also increased the expression levels of E-cadherin and Occludin in the colon and pro-inflammatory cytokines and TLR4 in ileum and colon. The BLS mix also increased Simpson’s diversity index in the gut microbiota and the relative abundances of o_Bacteroidetes and f_Ruminococcaceae, but it decreased the relative abundances of Blautia, and Clostridium. Collectively, these findings suggested that dietary BLS mix supplementation efficaciously promotes intestinal health through the modulation of gut microbiota in weaned piglets.