Fig. 4

The concentrations of BAs, physiological changes, and microbial composition after HFD feeding or BA supplementation. a The concentrations of total BAs, primary BAs, and secondary BAs in caecal content in control, control + BA, and HFD groups (n = 7 per group). Data are expressed as mean ± SEM. Differences were assessed by the Mann–Whitney U test. Significance was established at adjusted P < 0.05 (*P < 0.05, **P < 0.01) with FDR = 0.05. b Heatmaps of BA alteration, microbiome alteration, and their correlations. The two heatmaps with gradient colors of white to orange illustrate the mean concentration of BAs and the mean abundance of microbes in control, HFD, and control + BA groups. The heatmaps with gradient colors of green, white, and red illustrate the Spearman correlations of the relative abundance of microbes and the concentrations of BAs among the samples from the control (n = 5) and control + BA (n = 5) groups. The r values are represented by gradient colors, where red and green cells indicate positive and negative correlations, respectively; *P < 0.05. c Body weight, abdomen adipose tissue weight, liver weight, and the concentration of serum total cholesterol in control, control + BA, and HFD groups (n = 7 per group). Differences are assessed by the Mann–Whitney U test. Significance is established at adjusted P < 0.05 (*P < 0.05) with FDR = 0.05. d Principle coordinate analysis (PCOA) plot is generated using OTU metrics based on the Bray–Curtis similarity for the samples in control, control + BA, and HFD groups (n = 5 per group). The center point coordinate of the ellipse is the mean value of PC1 and PC2, respectively, in the corresponding group. The length of the semi-major axis and semi-minor axes of the ellipse is 1.5-fold SD of PC1 and PC2, respectively. The ellipse is rotated to the direction of largest variation of the corresponding group. The values of PC1 and PC2 are shown in bar plots. Data are expressed as mean ± SEM. Differences were assessed by the Mann–Whitney U test. Significance was established at P < 0.05 (***P < 0.001). e Hierarchical clustering based on the Bray–Curtis similarity for the microbial composition of caecal content of each sample in control, control + BA, and HFD groups (n = 5 per group). f The mean percentage of the total population at phylum levels in the caecal microbiota in control, control + BA, and HFD groups (n = 5 per group). Differences were assessed by the Mann–Whitney U test. Significance was established at P < 0.05 (*P < 0.05, **P < 0.01)