Alterations of Bile Acids and Gut Microbiota in Obesity Induced by High Fat Diet in Rat Model.

Obesity has become a worldwide health issue and has attracted much public attention. In the current study, we aim to elucidate the roles of bile acids and their associations with gut microbiota during obesity development, employing high fat diet (HFD)-induced obesity in a rat model. We collected feces and plasma, liver tissues, and segments of intestinal tissues and a developed bile acids quantification method by employing an ultraperformance liquid chromatography coupled with mass spectrometry detection (UPLC-MS) strategy. We then assessed bile acids fluxes in the biological matrixes collected. We found that, irrespective of dietary regimes, taurine-conjugated bile acids were the dominant species in the liver whereas unconjugated bile acids were in plasma. However, HFD caused slight increases in the total bile acids pool and particularly the increases in the levels of deoxycholic acid (DCA) (138.67 ± 37.225 nmol/L in control group, 242.61 ± 43.16 nmol/L in HFD group, p = 0.014) and taurodeoxycholic acid (TDCA) (2.8 ± 0.247 nmol/g in control group, 4.5 ± 0.386 nmol/g in HFD group, p = 0.0018) in plasma and liver tissues, respectively, which were consistent with the increased levels of DCA in intestinal tissues and feces. These changes are correlated to an increase in abundance of genera Blautia, Coprococcus, Intestinimonas, Lactococcus, Roseburia, and Ruminococcus. Our investigation revealed the fluxes of bile acids and their association with gut microbiota during obesity development and explicated unfavorable impact of HFD on health.