Probiotic-fermented rice buckwheat alleviates high-fat diet-induced hyperlipidemia in mice by suppressing lipid accumulation and modulating gut microbiota

[Display omitted] •Fermented rice buckwheat (FRB) increases bioactive components compared with rice buckwheat (RB).•FRB exhibits better hypolipidemic effects than those of RB.•FRB alleviates dyslipidemia, oxidative stress and chronic inflammation in HFD-induced mice.•FRB inhibits cholesterol synthesis and lipogenesis, and promotes lipolysis in HFD-induced mice.•FRB ameliorates lipid accumulation is associated with the modulation of the gut microbiota. Hyperlipidemia is associated with lipid metabolic disorders, chronic inflammation, and intestinal dysbiosis. Previous studies have shown that the metabolic improvement of high-fat diet (HFD)-induced mice by buckwheat is correlated with gut microbiota; however, the anti-hyperlipidemia effects and potential mechanism of probiotics-fermented rice buckwheat (FRB) are not well understood. Here, we aimed to investigate the lipid-lowering and gut microbiota regulation of FRB in HFD-induced hyperlipidemic mice. We observed that probiotic fermentation markedly increased the contents of γ-aminobutyric acid, rutin, total polyphenols, and total flavonoids in rice buckwheat. FRB supplementation over eight weeks significantly reduced body weight gain and visceral obesity, as well as alleviating dyslipidemia in HFD-fed mice. Moreover, FRB treatment effectively ameliorated oxidative stress and chronic inflammation. We further demonstrated that FRB intervention significantly inhibited hepatic cholesterol synthesis and lipogenesis, and promoted lipolysis. More important, FRB treatment reversed HFD-induced gut dysbiosis by decreasing the ratio of Firmicutes to Bacteroidetes and increasing the abundance of SCFA-producing bacteria such as Bacteroides, Lactobacillus, and Blautia, along with increasing the total SCFAs contents. Overall, these results show that FRB is a beneficial nutraceutical for hyperlipidemia amelioration.