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.