Buckwheat‐resistant starch (BRS) has shown to be a nutrient capable of lowering cholesterol and reducing obesity. In this study, the regulatory effects of tartary buckwheat starch on blood lipid level and gut microbiota (Lactobacillus, Bifidobacterium, Enterococcus, and Escherichia coli) in mice fed with a high‐fat diet was investigated. Male C57BL/6 mice were separately fed with a normal diet (CON), a high‐fat diet (HFD), and high‐fat diet supplemented with buckwheat‐resistant starch (HFD+BRS) for 6 weeks. After the feedings, lipid profile, blood glucose, plasma levels of cytokines, short‐chain fatty acid content in the colon and intestinal flora of fecal were measured. Furthermore, the antioxidant indices of the liver and duodenum tissues were measured to evaluate the antioxidant capacity of mice. Significantly reduced plasma levels of total cholesterol (TC), triglyceride (TG), glucose, and cytokines were observed in the HFD+BRS group, accompanied by an increased antioxidant capacity in the liver and duodenum. In addition, supplementation with BRS significantly inhibited the increase in plasma lipopolysaccharide, tumor necrosis factor‐α, and interleukin‐6 levels. Gut microbiota composition was regulated by the supplement of BRS, which promoted the growth of Lactobacillus, Bifidobacterium, and Enterococcus, as well as inhibited the growth of Escherichia coli. In contrast to the HFD group, the content of short‐chain fatty acids in mice colon increased in the BRS group. In conclusion, BRS benefited the cholesterol and glucose metabolism, as well as optimized gut microbiota composition in mice fed with a high‐fat diet. Practical Application This study identified the beneficial effects of tartary buckwheat‐resistant starch on the regulation of blood lipids and intestinal flora in mice fed a high‐fat diet. The result of this study will provide a basis for the development of probiotic products supplemented with tartary buckwheat‐resistant starch and direction for further research.

Resistant starch (RS) is closely related to the composition of intestinal flora. Based on many studies on the physiological functions of probiotics and short‐chain fatty acids (SCFAs), it is possible that RS can improve the intestinal health of the host. Therefore, we speculated that tartary buckwheat‐resistant starch (TBRS) can also regulate the intestinal flora disorder caused by high‐fat diet. We randomly divided 36 SPF C57BL/6J mice into low‐fat diet, high‐fat diet (HF‐CS), high‐fat diet supplemented with TBRS (HF‐BRS), and high‐fat diet supplemented with corn‐resistant starch (HF‐CRS). We analyzed the diversity and richness of gut microbiota based on PCR and Illumina high‐throughput sequencing technology. In community abundance, the HF‐BRS group was significantly higher than the other three groups ( p < .05). TBRS improved the gut microbiota dysbiosis, including decreasing the Firmicutes ‐to‐ Bacteroidetes ratios (F/B) and contributing to the growth of Bacteroides and Blautia as well significantly inhibiting the growth of Bifidobacterium , Faecalibaculum , and Erysipelatoclostridium . We also analyzed the production of SCFAs by GC‐MS, and the concentration of total SCFAs increased in the HF‐CS group. However, TBRS significantly increased the production of SCFAs, especially the propionate concentration compared with the HF‐CRS group ( p < .05). These results elucidated that TBRS has the potential to improve intestinal health by altering the structure of gut microbiota and increasing the production of SCFAs. Our findings have important implications for TBRS as functional food ingredient to manipulate intestinal microflora.

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The aim of this study was to evaluate the effect of buckwheat fermented milk on intestinal flora and short-chain fatty acids (SCFAs) of rats fed a high-fat diet (HFD). Buckwheat fermented milk was made with Lactobacillus plantarum ST-Ⅲ, Lactobacillus bulgaricus, and Streptococcus thermophilus. Thirty-six males C57BL/6 rats (aged 3 weeks and with 9 to 12 g weight) were subjected to a 2-week adaptive period on a normal diet. After a week of acclimatization, the rats were randomly divided into three groups with 12 rats in each group. The high-fat diet with fermented milk (HFDFM) group received HFD supplemented with fermented milk, and the high-fat diet supplemented with buckwheat fermented milk (HFDBFM) group received HFD plus buckwheat fermented milk. Besides, the gavage dose was 0.4 mL/day. After the feedings, colon levels of cytokines and antioxidant indices of the liver, colon, and duodenum tissues were measured. The composition of intestinal flora of rats and the content of SCFAs were determined by gas chromatography-mass spectrometry and Illumina high-throughput sequencing technology. Supplementation with buckwheat fermented milk significantly inhibited the increases in lipopolysaccharide levels in colon and antioxidant indexes in the HFD-fed rats. In addition, buckwheat fermented milk could significantly enhance Firmicutes and decrease Bacteroidetes compared to HFDFM. In addition, SCFA concentrations in HFDBFM were higher than other groups. In conclusion, buckwheat fermented milk can alleviate the damage of HFD to intestinal flora of rats. It modulates microbiota composition and SCFA concentrations to balance the intestinal environment, which will benefit to rats' intestinal health.Practical Application: This study explored the effect of buckwheat fermented milk on the regulation of intestinal microflora and SCFAs in rats fed a high-fat diet. It provides new ideas for the development of buckwheat fermented food.

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