alleviates intestinal inflammation and promotes microbiota-mediated protection against fatal infections.

The fatal impairment of the intestinal mucosal barrier of chicks caused by significantly resulting economic losses in the modern poultry industry. Probiotics are recognized for beneficially influencing host immune responses, promoting maintenance of intestinal epithelial integrity, antagonistic activity against pathogenic microorganisms and health-promoting properties. Some basic studies attest to probiotic capabilities and show that could protect intestinal mucosa from injury in animals infected with Typhimurium. However, the mechanisms underlying its protective effects in chicks are still not fully understood. Here, we used the chick infection model combined with histological, immunological, and molecular approaches to address this question. The results indicated that significantly reduced the diarrhea rate and increased the daily weight gain and survival rate of chicks infected with Typhimurium. Furthermore, we found that markedly improved the immunity of gut mucosa by reducing apoptotic cells, hence effectively inhibiting intestinal inflammation. Notably, pre-treatment chicks with balanced the expression of interleukin-1β and interleukin-18, moderated endotoxin and D-lactic acid levels, and expanded tight junction protein levels (Zonula occluden-1 and Claudin-1), enhanced the function of the intestinal mucosal epithelial cells. Additionally, investigations using full-length 16S rRNA sequencing also demonstrated that greatly weakened the adhesion of , the mainly manifestation is the improvement of the diversity of intestinal microbiota in infected chicks. Collectively, these results showed the application of against fatal infection by enhancing barrier integrity and the stability of the gut microbiota and reducing inflammation in new hatch chicks, offering new antibiotic alternatives for farming animals.