Fig. 6
Reduction of gut microbiota and BAs weakened the thermogenesis-promoting effect of AA. a Rectal temperature. b Representative infrared images. The black arrow points to the temperature measurement location, including the eyes, back, and abdomen. (c–e) Surface body temperature including eye temperature (c), dorsal temperature (d), and ventral temperature (e). (f) The ratio of energy intake, body weight, white adipose tissue (WAT) weight, and brown adipose tissue (BAT) weight of CH + AA + ABX to energy intake, body weight, WAT weight, and BAT weight of CH + AA, respectively. Immunohistochemical staining (g) for uncoupling protein 1 (UCP1) in WAT (Magnification = 100×; scale bar, 100 μm) and BAT (Magnification = 200×; scale bar, 50 μm), and the relative expression of UCP1 in WAT (h) and BAT (i). CH + AA represents rats intermittently exposed to cold water and fed AA, while CH + AA + ABX represents rats intermittently exposed to cold water and fed AA and antibiotics. Data were expressed as mean ± standard deviation (SD) (n = 6 rats/group). Differences were evaluated by unpaired two-tailed Student’s t-test (*P < 0.05, **P < 0.01, and ***P < 0.001)