Bacillus subtilis MZ-01 alleviates diarrhea caused by ETEC K88 by reducing inflammation and promoting intestinal health

Abstract Aims The purpose of this study was to investigate the effects of Bacillus subtilis supplementation on the health of weaned piglets and whether Bacillus subtilis supplementation can reduce the damage of piglets induced by ETEC K88. Methods and Results The experiment was designed with a 2 × 2 factorial arrangement, comprising the control (CON) group, Bacillus subtilis (PRO) group, Escherichia coli K88 (ETEC) group, and Bacillus subtilis + ETEC (PRO + ETEC) group. Regardless of the presence of ETEC, the addition of PRO increased the piglets' final body weight (FW), average daily gain (ADG), and daily feed intake (ADFI). Additionally, PRO primarily achieves a reduction in heat-stable enterotoxin (ST) levels, suppresses the expression of NF-κB, TLR4, and MyD88 mRNA in the jejunum and ileum, lowers pro-inflammatory factors in the blood and small intestine, enhances the expression of tight junction proteins in the small intestine, improves the composition of the colonic microbiota, increases colonic short-chain fatty acids (SCFAs) contents, thereby alleviates diarrhea and mitigates bodily damage caused by ETEC K88 infection. Conclusion The addition of Bacillus subtilis MZ-01 alleviated ETEC K88-induced piglet diarrhoea by reducing heat-stable enterotoxin levels, decreasing pro-inflammatory factors in the blood and intestine, and enhancing the intestinal barrier and tight junction proteins.