Bacillus licheniformis-Fermented Products Reduce Diarrhea Incidence and Alter the Fecal Microbiota Community in Weaning Piglets

SIMPLE SUMMARY: Antibiotics have been commonly used worldwide as growth promoters and for prophylactic treatment of diarrhea in weaning piglets. However, The European Union has banned the use of antibiotic growth promoters in animal production. Therefore, finding alternative solutions for preventing diarrhea in weaning piglets is urgent. Modulation of gut microbiota composition by probiotics has a beneficial effect on animal health. In this study, we assessed the effects of Bacillus licheniformis-fermented products on diarrhea incidence and the fecal microbiome composition in weaning piglets. Results showed that B. licheniformis-fermented products could improve diarrhea incidence and the fecal microbiota community in weaning piglets. These findings indicate that B. licheniformis-fermented products have the potential for development as feed additives and use as possible substitutes for antibiotics to prevent postweaning diarrhea in the pig industry. ABSTRACT: Prophylactic use of antibiotics in-feed has been effective in decreasing the incidence of diarrhea in weaning piglets. However, the overuse of antibiotics as prophylactic or therapeutic agents in animal feed leads to the evolution of drug-resistant bacteria and antibiotic residues in pigs. This study investigated the effects of Bacillus licheniformis-fermented products on diarrhea incidence and the fecal microbial community in weaning piglets. A total of 120 crossbred piglets with an average initial body weight of 9.87 ± 1.43 kg were randomly allotted to four dietary treatments consisting of three replicate stalls with 10 piglets in each. The dietary treatments comprised a basal diet as control, control plus 1 g/kg or 4.5 g/kg of B. licheniformis-fermented products, and control plus 30 mg/kg antibiotics (bacitracin methylene disalicylate). Results showed that 4.5 g/kg of B. licheniformis-fermented product supplementation significantly reduced diarrhea incidence in weaning piglets. Principal coordinate analysis and a heatmap of species abundance indicated distinct clusters between the groups treated with antibiotics and B. licheniformis-fermented products. The bacterial richness and evenness in the feces decreased in weaning piglets fed 1 g/kg of B. licheniformis-fermented products and antibiotics. The abundance of the genera [Ruminococcus] gauvreauii group, Ruminococcaceae UCG-005, and Ruminococcaceae UCG-008 in the feces decreased in weaning piglets fed B. licheniformis-fermented products or antibiotics. The average abundance of the genus Prevotella 9 in the feces was positively correlated with the concentration of B. licheniformis-fermented products and negatively correlated with the diarrhea incidence in weaning piglets. Furthermore, the average abundance of the genus Prevotella 9 in the feces was positively correlated with the growth performance of weaning piglets. These results demonstrate that B. licheniformis-fermented products can improve diarrhea incidence and fecal microflora composition in weaning piglets.