The difference of regulatory effect of two Inonotus obliquus extracts on high‐fat diet mice in relation to the fatty acid elongation function of gut microbiota

Obesity is a disease that causes metabolic disorders in the human body and is closely related to intestinal microbes. This experiment compares the therapeutic effects of two Inonotus obliquus extracts on high‐fat diet (HFD) mice and explores the effects and mechanisms of intestinal flora and its metabolites. The energy intake (EI), weight gain (BWG), fecal flora diversity, fecal and urine metabolites, and fecal triglycerides (TG) of mice were measured at 4 temporal points. We found that due to the difference in energy intake between the two groups in the early stage of the experiment, the ethanol extract of Inonotus obliquus (IOE) had a stronger effect on the accumulated BWG than the polysaccharide (IOP) of Inonotus obliquus at the end of the experiment. Moreover, the difference caused by IOE and IOP intake was the largest in the second week, in four temporal points. Compared with IOP, IOE in the second week can reduce EI, fecal short‐chain fatty acids (SCFA) and TG, reduce host metabolism, increase fecal Akkermansia and fatty acid elongation, and increase host substrate phosphorylation. The change trend of the fatty acid elongation P value from 2 to 14 weeks is consistent with the overall difference trend between the two groups. The difference in the regulating effect of the two Inonotus obliquus extracts on HFD mice is related to the fatty acid elongation function of the intestinal flora, which leads to the reduction of IOE and the effect of BWG is better than IOP. It provides a theoretical reference for the development of functional food using the extract of Inonotus obliquus.