Fig. 2

HFD-induced microbial composition changes in mouse caecum. a Principle coordinate analysis (PCOA) plot is generated using OTU metrics based on the Bray–Curtis similarity for the samples in control (n = 5) and HFD (n = 5) groups. 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 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 are assessed by the Mann–Whitney U test. Significance is established at P < 0.05 (***P < 0.001). b Hierarchical clustering based on the Bray–Curtis similarity of caecal content microbial composition in control (n = 5) and HFD (n = 5) groups. c The mean percentage of the total population at phylum levels in the caecal microbiota in control (n = 5) and HFD (n = 5) groups. Differences are assessed by the Mann–Whitney U test. Significance is established at P < 0.05 (*P < 0.05, **P < 0.01). d Linear discriminant analysis (LDA) effect size method was performed to compare taxa between control (red; n = 5) and HFD (green; n = 5) groups. The bar plot lists the significantly differential taxa based on effect size (LDA score (log 10) > 2). Enriched taxa in controls (negative LDA score), and enriched taxa in HFD (positive LDA score). e Spearman correlations of the relative abundance of differential microbial species selected by the LDA effect size method and the concentrations of BAs among the samples from control (n = 5) and HFD (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