Fig. 9.

In vivo effects of 17β-estradiol on the gene expression of estrogen receptors (a–c) and aromatase CYP19 (d–e) in the head kidney. Fish were fed for 14 days with control food (non-E2) or food treated with 17β-estradiol (E2, 20 mg/kg food). On day 14 of E2 feeding, fish were injected i.p. with A. salmonicida (4 × 10⁸ bacteria in 250 μL PBS per fish). At 24 and 96 h post-infection (hpi), the head kidneys were collected, and gene expression was measured. Changes in gene expression are shown as x-fold increase compared to control group (non-E2) and standardized for the housekeeping gene 40S ribosomal protein s11. Averages and S.E. (n = 7). Stars (*) indicate statistically significant differences between control (CTR) and E2-treated animals (*p ≤ 0.05, **p ≤ 0.001); number signs (#) indicate statistically significant differences between time points of infection (24 vs 96 hpi) (#p ≤ 0.05, ##p ≤ 0.001, ###p ≤ 0.0001)