Alterations in intestinal microbiota by alginate oligosaccharide improve intestinal barrier integrity in weaned pigs

Abstract

• AOS enhances the intestinal barrier integrity by activating the AMPK pathway. • AOS attenuates intestinal inflammatory reactions by inhibiting the NF-κB pathway. • These changes are associated with alterations in intestinal microbiota and microbial metabolites caused by AOS. In this study, we investigated the effects of alginate oligosaccharide (AOS) on the intestinal microbiota and intestinal barrier integrity in weaned pigs. Twenty-four weaned pigs were equally assigned to either a control group (fed the basal diet) or an AOS group (fed the basal diet supplemented with 100 mg/kg AOS). AOS upregulated caecal and colonic tight junction protein expression levels but downregulated caecal pro-inflammatory cytokine expression levels. AOS increased the caecal and colonic abundance of phospho-adenosine 5′-monophosphate-activated protein kinase α (p-AMPKα) and decreased the abundance of caecal intra-nuclear nuclear factor-κB (NF-κB) p65. Furthermore, AOS increased the caecal prevalence of several bacteria belonging to Bacteroidetes and Firmicutes as well as the caecal and colonic concentrations of short-chain fatty acids (SCFAs). Thus, AOS alters the intestinal microbiota composition and SCFA concentrations in weaned pigs, thereby influencing the intestinal inflammatory responses and barrier integrity by regulating NF-κB and AMPK pathways.