Highland barley improves lipid metabolism, liver injury, antioxidant capacities and liver functions in high-fat/cholesterol diet mice based on gut microbiota and LC-MS metabonomics

Highland barley (HB) possesses a series of properties such as regulating lipid metabolism and attenuating liver injury. Our study aimed to investigate the effect of HB, highland barley bran (HBB), whole grain highland barley (WGHB) on lipid metabolism, liver inflammation, gut microbiota and metabolite profiles in high-fat/cholesterol (HFCD) diet mice. 5 treatment groups were fed a normal control diet or a HFCD with or without HB supplementation for 10 weeks. The results showed that HB especially HBB significantly improved lipid parameters, liver function and injury and blood glucose indexes related to hyperlipidemia compared with HFCD group. In addition, HBB recovered the disorder of gut microbiota by increasing Bacteroidetes/Firmicutes ratio and Lactobacillus and Allobaculum abundances, and decreasing Proteobacteria abundance related to lipid metabolism bacteria. HBB enhanced the levels of 6 short chain fatty acids induced by HFCD. Fecal metabolomics analysis showed that the important differential metabolites between HBB group and HFCD group were deoxycholic acid, myclobutanil and cis-4-Hydroxy-D-proline, and the important differential metabolic pathways were arachidonic acid metabolism, tyrosine metabolism and bile secretion. Results suggested that HBB was an effective dietary intervention candidate to ameliorate hyperlipidemia.