Stachyose protects intestinal mucosal barrier via promotion of tight junction and Lactobacillus casei-drived inhibition of apoptosis in juvenile turbot, Scophthalmus maximus L.

Abstract

This study aimed to elucidate the possible beneficial effects of stachyose on cottonseed meal-induced intestinal barrier damage and to investigate the underlying mechanism in turbot (Scophthalmus maximus L.). A 12-week feeding trial was conducted using four isonitrogenous and isolipidic diets: a fishmeal-based diet (FM), a diet with cottonseed meal replacing 40% fish meal protein (CM), CM supplemented with 1.4% (S1) and 2.8% (S2) stachyose. Dietary stachyose at 2.8% mitigated cottonseed meal-induced depression of the growth performance and feed utilization, improved the intestinal morphology, and decreased the D-lactate content and activity of diamine oxidase in serum. The protective effects of stachyose were associated with enhancement in expression of intestinal tight junction proteins and inhibition of apoptosis. An additional in vitro study showed that Lactobacillus casei, greatly enriched in the intestine of fish fed the S2 diet, alleviated gossypol-induced apoptosis in epithelial cells. The function of L. casei was found to be associated with the activation of Akt and stimulation of epithelial cell proliferation in the intestine. Collectively, these results provide novel insights into the regulatory role of stachyose in modulation of intestinal microbiota and mucosal barrier function, as well as a microbiome-targeted strategy to improve intestinal health of fish.