Lactobacillus reuteri alleviates LPS-induced intestinal mucosal damage by stimulating the expansion of intestinal stem cells via activation of the Wnt/β-catenin signaling pathway in broilers.

The continuous expansion of intestinal stem cells (ISCs) is crucial for maintaining the renewal of the intestinal epithelium, particularly in inflammatory conditions. It remains largely unknown how the internal microbiota repair damage to the internal mucosal barrier. Hence, investigating potential anti-inflammatory probiotics from the intestinal symbolic microbes of broilers and analyzing their mechanism of action to support the intestinal mucosal barrier function can offer novel regulatory tools to alleviate broiler enteritis. In this research, we utilized in vivo broilers plus ex vivo organoids model to thoroughly examine the effectiveness of Lactobacillus reuteri (LR) in protecting the integrity of the intestinal mucosa during lipopolysaccharide-induced (LPS-induced) enteritis in broilers. The findings indicated that LR feeding maintained intestinal morphological and structural integrity, enhanced proliferation of intestinal epithelial cells, and inhibited cell apoptosis and inflammatory response against the deleterious effects triggered by LPS. Simultaneously, LR enhanced ISCs activity and stimulated intestinal epithelial regeneration to protect the intestinal barrier during LPS-induced injury conditions. The coculture system of LR and ileum organoids revealed that LR increased the growth of organoids and attenuated LPS-stimulated damage to organoids. Furthermore, the LPS-induced decrease in ISC activity was rescued by reactivation of Wnt/β-catenin signaling by LR ex vivo and in vivo. This research revealed that LR promoted the expansion of ISCs and intestinal epithelial cell renewal by regulating the Wnt/β-catenin signaling pathway, thereby maintaining the integrity of the intestinal mucosal barrier. This finding provided theoretical support for lactobacillus as a probiotic additive in livestock feed to improve intestinal inflammation and treat intestinal diseases.