Endogenous bile acids are associated with body lipid accumulation in non-diet induced obese pigs

Abstract

Abstract Background Non-diet-induced obesity has been difficult to improve due to the complex etiology. Pigs can serve as an animal model for biomedical researches due to their physiological similarities to humans. This study first explored the differences in endogenous bile acids profiles (content and composition) between lean and obese pigs when they were fed to the same diet. Then, the effects of the characteristic bile acids within obese pigs on lipid accumulation were further verified by using 3T3-L1 adipocyte cells model. Methods Fourteen pigs including lean and obese pigs with body weight about 80 kg were fed the same diet with a level of feeding at approximately 3% of their respective body weight daily for 42d. The 3T3-L1 pre-adipocytes were cultured in a medium with high glucose levels, and then differentiated into mature adipocytes using differentiation medium. Results There was a significant difference in endogenous bile acids profiles between obese and lean pigs. The obesity had a strong correlation with isoallolithocholic acid and 3-oxodeoxycholic acid in colonic digesta of pigs, and isoallolithocholic acid enhanced lipid content in 3T3-L1 adipocytes. The differential bile acids between obese and lean pigs may be caused by the differences in gut microorganisms. Conclusion The results provide evidences that the obesity of obese pigs is independent of dietary nutrients intake, but closely related to endogenous bile acids, implying that bile acids may be the targets to prevent non-diet-induced obesity.