Gut microbiota mediates the effects of inulin on enhancing sulfomucin production and mucosal barrier function in a pig model.

Dietary fibers (DFs) have many beneficial effects on intestinal health by ameliorating intestinal inflammation and modulating the microbial community composition, thereby affecting the barrier function. This study aims to characterize the gut microbiota of pigs fed with DFs, revealing a link between the intestinal microbiota and mucin chemotypes. Pigs (six per group) were randomly allotted to consume one of the following diets: control (CON) or a diet supplemented with 5% microcrystalline cellulose (MCC) or inulin (INU) for 72 days. We found that INU but not MCC enhanced the colonic barrier function by promoting the expression of ZO-1, Occludin and MUC2 and reducing the colonic crypt depth. INU increased sulfomucin production and mRNA levels of sulfotransferases Gal3ST1 and Gal3ST2. Goblet cells in the ileum were found to contain predominantly sialomucins while colonic goblet cells were dominated by sulfomucins with sialomucins absent. DF consumption increased the concentrations of short-chain fatty acids (SCFAs) of the ileum and colon compared to the CON diet. Moreover, the results of 16S rRNA gene sequencing analysis revealed that DFs significantly altered the composition of ileal and colonic mucosal microbiota. Network analysis indicated that INU-induced changes in bacterial genera and SCFAs, such as Akkermansia and butyrate, were significantly related with sulfomucins and the mucosal barrier function-gene in pigs. Collectively, these findings suggest that the intestinal mucosal microbiota and SCFAs induced by INU play a crucial role in modulating the chemotypes of mucin and the barrier function.