Dietary Bacillus subtilis PB6 Enhances Reproductive Performance by Modulating Gut Microbiota, Barrier Function, and Inflammation in Clostridium perfringens Type A-Infected Sows

Bacillus subtilis is aerobic or facultatively anaerobic. After entering the gastrointestinal tract, its spores germinate and colonize the gut, inhibiting the growth of harmful aerobic bacteria (Escherichia coli, Streptococcus, Staphylococcus aureus). However, it remains unclear whether B. subtilis can inhibit Clostridium perfringens type A infection. In this study, B. subtilis PB6 was added to the diets of pregnant sows infected with Clostridium perfringens type A, which significantly improved the reproductive performance and reduced the incidence of bloat in sows and diarrhea in neonatal piglets. The treatment significantly increased the abundance of intestinal probiotics (B. subtilis, Lactobacillus, Limosilactobacillus reuteri, Lactobacillus johnsonii, Muribaculaceae, Lactobacillus amylovorus, and Lactobacillus reuteri) in sows and decreased the relative abundance of Clostridium perfringens type A after feeding B. subtilis administration. These probiotics can repair the intestinal tissue and improve intestinal histomorphology, and enhance the expression of MUC2 and sIgA in sows, thereby further strengthening the mucosal immune function. B. subtilis can also reduce the levels of inflammatory factors (CRP, IL-1β, and IFN-γ) and attenuate the inflammatory response in sows and neonatal piglets. Taken together, our results suggest that dietary supplementation with B. subtilis PB6 could reduce bloat in sows and diarrhea in piglets while improving intestinal barrier function and microbial balance in sows.