Fig. 3

AA reshaped the composition and function of gut microbiota. a Principal component analysis (PCA) based on weighted_normalized_unifrac distance metrics of operational taxonomic units (OTUs). b Percent abundance of bacteria at the phylum level. c Firmicutes/Bacteroidetes ratio.  The relative abundance of bacteria at the family level (d) and the genus level (e). The relative abundance of genes involved in energy production and conversion (f), and bile acid metabolism (g) predicted by COG. The relative abundance of genes involved in carbohydrate digestion and absorption (h) and PPAR signaling pathway (i) in the KEGG pathway on level III. (j−m) The gene levels of sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase (j), stearoyl-CoA desaturase (k), Na⁺-transporting ATPase (l), and K⁺-transporting ATPase (m). Control, CH, and CH + AA represent groups intermittently exposed to warm water (32 ± 0.5 °C), cold water (3.5 ± 0.5 °C), and cold water plus AA, respectively. Data were expressed as mean ± standard deviation (SD) (n = 6 rats/group). Differences were evaluated by one-way ANOVA with a post hoc Student–Newman–Keuls test (*P < 0.05, **P < 0.01, and ***P < 0.001, and ns represents no significant difference)