The mice were treated with a cocktail of antibiotics (ABX) containing 1 g/L ampicillin, neomycin sulfate and metronidazole and 0.5 g/L vancomycin for three weeks. Then, the mammary gland, ileum and colon tissues were collected. (A-C) The AhR, Cyp1a1 and Cyp1b1 mRNA levels in the mammary glands were identified using qPCR (n = 3). (D) Protein expression of AhR and Cyp1a1 in mammary glands of control and ABX-treated mice (n = 3). The levels of AhR (E), Cyp1a1 (F), IL-22 (G), Reg3g (H) and Reg3β (I) mRNA in ileum and colon tissues from control and ABX-treated mice were measured by qPCR (n = 3). Student’s t test were applied for statistical analysis in (A-C) and (E-I) and the date are shown as means ± SEM. *p < 0.05, **p < 0.01 and ***p < 0.001 indicate significant differences from each group. ABX, a cocktail of antibiotics.