Effects of Five Food Materials on the Abundance of Gut Microbiota and Fecal Short-Chain Fatty Acids in High-Fat Diet-Induced Obese Rats

Although banana powder (BP), konjac powder (KP), resistant dextrin (RD), corn starch (CS) and L-carnitine (LC) have been reported for their anti-obesity properties, their effects on the gut microbiota and its metabolites, and the differences in anti-obesity mechanisms related to the gut microbiota are still unknown. In this study, high-throughput sequencing and high performance liquid chromatography (HPLC) were used to detect the gut microbiota profile and the amount of short-chain fatty acids (SCFAs) in the feces of high-fat diet-induced obese rats, respectively. Results showed that the probiotic genera Ruminococcus_2, Coprococcus_2 and Ruminiclostridium_5 were the main bacterial genera in the CS, BP and RD groups, respectively. Spearman correlation analysis and canonical correlation analysis (CCA) demonstrated that glucolipid metabolism parameters were related to changes in the gut microbiota. The relative contributions of soluble dietary fiber-rich diets (konjac powder and resistant dextrin) and insoluble dietary fiber (resistant starch)-rich diets (banana powder and corn starch) to producing SCFAs were equivalent, and greater than that of L-carnitine (LC). The ability of the five materials to promote the growth of probiotics and inhibit the proliferation of harmful bacteria in the gut was in the decreasing order of RD > BP > CS > KP, and the ability to increase fecal SCFAs was in the decreasing order of BP > RD > CS > KP, while LC showed little effect on the gut microbiota or SCFAs. CCA analysis showed that the degree of correlation between glucolipid metabolism parameters and the intestinal microbial community decreased in the following order: blood glucose (GLU) > high-density lipoprotein cholesterol (HDL-C) > total cholesterol (TC) > low-density lipoprotein cholesterol (LDL-C) > triacylglycerol (TG). Spearman correlation analysis showed that Ruminococcus_2 was positively correlated with butyrate content, and Escherichia. Shigella was positively correlated with the contents of acetate, butyrate and total SCFAs.