Dietary supplementation of Bacillus subtilis influenced intestinal health of weaned pigs experimentally infected with a pathogenic E. coli

BackgroundThere is growing evidence to support the beneficial effects of supplementing direct-fed microbials (DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this study was to investigate dietary supplementation of Bacillus subtilis (DSM 25841) on growth performance, diarrhea, gut permeability and immunity of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli (E. coli).ResultsThe F18 E. coli infection reduced (P<0.05) growth performance and intestinal villi height, whereas increased (P<0.05) diarrhea and transcellular and paracellular permeability in the jejunum compared with non-challenged control. Supplementation of Bacillus subtilis linearly enhanced average daily gain of E. coli infected pigs from d 0 to 5 post-inoculation (PI) (P<0.05) and d 0 to 11 PI (P=0.058). Supplementation of high dose of Bacillus subtilis reduced (P<0.05) both transcellular and paracellular permeability on d 5 and d 11 PI compared with the E. coli infected pigs fed with control diet. E. coli infection up-regulated (P<0.05) the mRNA expression of SLC5A10 (soluble carrier family 5 member 10) and MUC2 (mucin 2) on d 5 PI, but down-regulated (P<0.05) expression of SLC5A10, MUC2, and CLDN1 on d 11 PI in jejunal mucosa when pigs were fed with the control diet. Supplementation of Bacillus subtilis linearly up-regulated (P<0.05) the mRNA expression of CFTR and ZO1 on d 5 PI and SLC5A10 and MUC2 on d 11 PI in jejunal mucosa of E. coli infected pigs. In addition, E. coli infection increased (P<0.05) the mRNA expression of several immune genes (IL1A, IL1B, and IL7 on d 5 PI, and IL1B, IL6, IL7, and TNF on d 11 PI) in the ileal mucosa of weaned pigs. Inclusion of Bacillus subtilis to control diet linearly down-regulated gene expression of IL1A on d 5 PI (P=0.07) and IL6 on d 11 PI (P<0.05) in ileal mucosa of E. coli infected pigs.ConclusionsSupplementation of Bacillus subtilis (DSM 25841) enhanced growth rate and improved gut barrier function of weaned pigs experimentally infected with a pathogenic E. coli.