Bacillus licheniformis Alleviates Clostridium perfringens-Induced Intestinal Injury in Mice Model by Modulating Inflammation, Apoptosis, and Cecal Microbial-Metabolic Responses.

Bacillus licheniformis (B. licheniformis) is a probiotic known for its ability to enhance host resistance against pathogenic infections. This study aimed to evaluate the protective effects and underlying mechanisms of B. licheniformis in a mouse model challenged with Clostridium perfringens (C. perfringens). C57BL/6J mice were pretreated with B. licheniformis for 21 days before oral infection with C. perfringens. The probiotic administration significantly prevented infection-induced weight loss and immune organ enlargement. Serum cytokine analysis revealed that B. licheniformis increased anti-inflammatory IL-4 and IL-10 levels while reducing pro-inflammatory IL-1β, IL-6, and TNF-α levels. Histological analysis showed that B. licheniformis preserved intestinal morphology and inhibited epithelial cell apoptosis. Moreover, the probiotic mitigated the infection-induced decline in volatile fatty acid (VFA) production. 16S rRNA gene sequencing revealed that B. licheniformis reshaped the cecal microbiota, characterized by the increased abundance of Lachnospiraceae_NK4A136_group, Muribaculaceae, and Parabacteroides, and reduced abundance of Alistipes. Untargeted metabolomic profiling identified differential metabolites-including D-glucono-1,5-lactone, D-erythrose 4-phosphate, and D-sedoheptulose 7-phosphate-enriched in the pentose phosphate pathway, suggesting a regulatory role in redox homeostasis and host response. Collectively, these results indicate that B. licheniformis exerts protective effects against C. perfringens infection by modulating inflammation, apoptosis, microbial composition, and metabolic pathways. This work provides new insights into the application of B. licheniformis as a functional microbial feed additive in livestock disease prevention.