Trans fatty acids alter the gut microbiota in high-fat-diet-induced obese rats.

The gut microbiota is directly influenced by dietary components, and it plays critical roles in chronic diseases. Excessive consumption of trans fatty acids (TFAs) is associated with obesity induced by alterations in gut microbiota, but the links between obesity and gut microbiota remain unclear. Therefore, studies examining the impact of TFAs on intestinal microflora are essential. In our study, we performed 16S rRNA gene sequencing on faecal samples from SD rats fed a basal diet (CON group), high-fat (HF) diet (DIO group) or TFA diets (1% TFA group and 8% TFA group) for 8 weeks to investigate the effects of TFA/HF diets on obesity and gut microbiota composition. We found that the TFAs/HF diets significantly induced obesity and changes in blood and brain physiological parameters of the rats. The relative abundance of the phyla Firmicutes and Bacteroidetes were inversely altered in the three test groups compared to the CON group. Proteobacteria increased slightly in the DIO, 1% TFA and 8% TFA groups. The genus Bacteroides increased in the DIO and 1% TFA groups, but Muribaculaceae decreased in all experimental groups compared to the controls. Moreover, significant differences were observed among clusters of orthologous group (COG) functional categories of the four dietary groups. Our observations suggested that the TFA/HF diets induced obesity and dysfunction of gut microbiota. Gut dysbiosis might mediate the obesity effects of TFA/HF diets.