Effects of Yam Gruel on Gut Microflora, Blood Glucose and Insulin in T2DM Rats

Objective: To investigate the effect of yam gruel on gut microflora, short chain fatty acids (SCFAs), blood glucose and insulin secretion in type 2 diabetic rats. Methods: 60 SPF Wister rats were randomly selected as blank group, and the remaining 50 rats were injected with streptozotocin (STZ) to make T2DM model. The rats were randomly divided into model group, yam gruel group, metformin group and combination group. The blank group and model group were given 5 mL normal saline, the yam gruel group was given 5 mL yam gruel every day, the metformin group was given metformin aqueous solution every day, and the combination group was given yam gruel and metformin for six weeks. The fasting blood glucose (FBG) of rats was detected every week. After the intervention, the blood glucose, fasting insulin (FINS), gut microflora composition and the content of SCFAs in feces were detected. Results: Compared with the blank group, the FBG, FINS and insulin resistance index of the model group were increased (P<0.05), the contents of acetic acid, propionic acid, butyric acid, OTUs, Chao1 index and Shannon index were significantly decreased (P<0.05), the relative abundance of Firmicutes, Verrucomicrobia, Oscellospira, Akkermansia and Clostridium decreased (P<0.05), and the relative abundance of Proteobacteria increased (P<0.05). After 4 weeks of intervention, blood glucose of rats in Yam gruel group decreased significantly (P<0.05). The FBG, FINS and HOMA-IR of the yam gruel group were significantly lower than those of model group (P<0.05). The FINS and HOMA-IR of the yam gruel group were no significant difference between metformin group, combination group. Compared with the model group, the contents of acetic acid, propionic acid and butyric acid of the yam gruel group increased (P<0.01), the OTUs, Firmicutes, Verrucomicrobia, Akkermansia and Clostridium of the yam gruel group increased, and Proteobacteria of the yam gruel group decreased (P<0.05). Conclusion: Yam gruel might improve insulin resistance and reduce blood glucose by improving intestinal microbial imbalance and increasing SCFAs content in T2DM rats.