Bacteriocin-Producing YRL45 Enhances Intestinal Immunity and Regulates Gut Microbiota in Mice.

Bacteriocins production is one of important beneficial characteristics of probiotics, which has antibacterial property against intestinal pathogens and is helpful for regulating intestinal flora. To investigate the impact of bacteriocin-producing probiotics on gut microecology, bacteriocin-producing YRL45 was orally administered to mice. The results revealed that it promoted the release of cytokines and improved the phagocytic activity of peritoneal macrophages to activate the immune regulation system. YRL45 was conducive to maintaining the morphology of colon tissue without inflammation and increasing the ratio of villus height to crypt depth in the ileum. The gene expression levels of , and were significantly up-regulated in the ileum and colon, and the gene expression of presented an upward trend with YRL45 intervention. Moreover, YRL45 remarkably enhanced the levels of immunoglobulins sIgA, IgA and IgG in the intestine of mice. The 16S rRNA gene analysis suggested that YRL45 administration up-regulated the relative abundance of the beneficial bacteria and , down-regulated the abundance of the pathogenic bacteria , and promoted the production of acetic acid, propionic acid and total short-chain fatty acids (SCFAs) in mice feces. Our findings indicated that YRL45 had the potential to be developed as a novel probiotic to regulate the intestinal barrier by altering gut microbiota to enhance intestinal immunity and ameliorate intestinal flora balance.