Xanthan gum oligosaccharides ameliorate glucose metabolism and related gut microbiota dysbiosis in type 2 diabetic mice

Xanthan gum oligosaccharides (XGOS) is a potentially commercial prebiotic. This study investigated the effects of XGOS on in vivo glucose metabolic parameters and gut microbiota structures in streptozotocin/high fat diet (STZ/HFD)-induced type 2 diabetic (T2D) mice and in vitro fecal fermentations using Hungate tubes and a Bionic Gastrointestinal Reactor (BGR). XGOS can efficiently ameliorate fasting hyperglycemia, glucose tolerance, in-sulin levels, pro-inflammatory cytokine interleukin-6 levels, and liver and pancreas pathological structures in T2D mice as compared with the model group. XGOS shaped the colonic microbiota structures by significantly reversing an increase in the Firmicutes to Bacteroidetes ratio and increasing Bacteroidales and Prevotella abundance in T2D mice and in vitro fecal fermentations. XGOS consumption increased by 83% of butyric acid in in vitro fecal fermentation using BGR, but not in T2D mice feces. Notably, XGOS degradation significantly stimulated expression of the short-chain fatty acid (SCFA) receptors, GPR41 and GPR43 in the liver. These findings indicated XGOS can ameliorate glucose metabolism in T2D mice, which was associated with the alteration of gut microbiota and the activation of SCFA receptors in the liver.