Highland barley attenuates high fat and cholesterol diet induced hyperlipidemia in mice revealed by 16S rRNA gene sequencing and untargeted metabolomics

In this study, highland barley (HB), HB bran (HBB) and whole grain HB (WGHB) alleviating hyperlipemia and liver inflammation in high fat and cholesterol diet (HFCD) mice was investigated. All 50 ICR mice were randomly allocated to 5 treatment groups: Normal control group, HFCD group, HB group, HBB group and WGHB group. The serum lipid profiles, liver and epididymal adipocyte histology, gut microbiota and untargeted metabolomics were adopted. The results suggested that HB especially HBB supplement could obviously decrease BW and BWG. Serum lipid profiles showed that HB especially HBB decreased TG, TC, LDL-C, ALT and AST levels while increased HDL-C level. Liver and epididymal adipocyte H&E staining also confirmed that hepatic injury and adipose accumulation were alleviated by HB especially HBB. Gut microbiota analysis indicated that HBB increased Bacteroidetes/Firmicutes ratio, Lactobacillus and Akkermansia muciniphila abundances while decreased Proteobacteria and Shigella abundances. Untargeted metabolomics results showed that HBB significantly increased deoxycholic acid levels compared with HFCD mice and HBB regulated arachidonic acid metabolism pathway. The obtained results provided important information about the processing of highland barley to retain its hypolipidemic effect and improve its acceptability and biosafety, and had a guiding effect on the development of HB products.