Lactobacillus paracasei influences the gut-microbiota-targeted metabolic modulation of the immune status of diarrheal mice

Koumiss is a traditional fermented drink widely consumed by nomads owing to its rich nutritional value and therapeutic effects. Lactobacillus paracasei is a bacterial strain isolated from koumiss and has a positive effect on diarrhea; however, the relationship between gut microbial dysbiosis and L. paracasei gut microbial metabolism remains unclear. Therefore, this study aimed to explore the anti-diarrheal activity of L. paracasei in a murine E. coli-induced diarrhea model to provide novel insights into its probiotic properties by analyzing its intestinal metabolites and effects on the intestinal barrier. Oral administration of the probiotic, L. paracasei, enhanced tight junction protein expression, alleviated clinical manifestations consistent with E. coli-induced diarrhea, and positively affected overall intestinal microecological homeostasis. Moreover, it increased the goblet cell count and the secretory immunoglobulin A content and regulated intestinal metabolism via gut microbes, consequently preventing E. coli-mediated disruption of the intestinal epithelial cell barrier.