Effects of long-term intake of whole wheat and aleurone-enriched Chinese steamed bread on gut microbiome and liver metabolome in mice fed high-fat diet

The protective effects of whole wheat flour steamed bread (WWF) and aleurone-enriched wheat flour steamed bread (AWF) on gut microbiota and metabolomic disorders were investigated in long-term high-fat diet (HFD) mice. The results showed that AWF and WWF significantly ameliorated dyslipidemia, hepatic oxidative stress, and damage in HFD-fed mice. The fecal microbiome analysis showed that AWF and WWF significantly increased diversity in the gut microbiota and altered the structure of the gut microbiota. An increase in Bacteroidetes (by 31% and 34%) and decrease in Firmicutes (by 17% and 17%) were observed in the AWF and WWF groups, respectively. Liver metabolomics demonstrated that AWF and WWF upregulated carboxylic acids and derivatives and organooxygen compounds, and downregulated fatty acyl compounds. Moreover, WWF significantly modulated the concentrations of steroids and steroid derivatives, and glycerophospholipids. Overall, our findings suggest that AWF and WWF dramatically altered hepatic metabolism concurrent with shifts in specific gut bacteria in C57BL/6J mice, exhibiting potential as functional foods for the prevention of metabolic disorders induced by a long-term HFD. Despite some differences, the AWF is generally able to achieve the same level of health benefits as the WWF.