Dietary Supplementation with Probiotic <i>Bacillus licheniformis S6</i> Improves Intestinal Integrity via Modulating Intestinal Barrier Function and Microbial Diversity in Weaned Piglets

Bacillus licheniformis (B. Licheniformis) has been considered to be an effective probiotic to maintain gut health and boost productivity in the pig industry, but there is no complete understanding of its mechanisms. We determined whether weaned piglets exposed to BL−S6 (probiotic) had altered intestinal barrier function or microbiota composition. In our study, 108 weaned piglets (54 barrows and 54 gilts) were divided equally into three groups, each with six pens and six piglets/pen, and fed a basal diet supplemented without or with antibiotic (40 g/t of Virginiamycin and 500 g/t of Chlortetracycline) or probiotic (1000 g/t of B. Licheniformis) for a 14-day trial. On day 14, one piglet was chosen from each pen to collect blood and intestinal samples. Compared with the control group, dietary supplementation with a probiotic promoted body weight (BW) gain and average daily gains (ADG) while reducing diarrhea incidence (p p SOD1, Nrf2, and HO-1 (p p p p = 0.09). Furthermore, weaning piglets who were given probiotics had a better balance of the cecum microbiota, with lactobacillus abundance increased and clostridium_sensu_stricto_1 abundance decreased. In conclusion, dietary supplementation with the probiotic BL−S6 promoted intestinal integrity, which was associated, in part, with modulating intestinal barrier function and microbial diversity in weaned piglets; it may offer a promising alternative to antibiotics to prevent diarrhea