stress response

Hybridization of one kidney of cortisol treated fish vs. one kidney of control fish. Kidneys were collected from untreated juvenile sea bream (n=4) and from fish, which received for 72h a coconut-oil implant containing 10mg/Kg (fish wet weight) (n=4) cortisol. Experiments were carried out at the University of the Algarve, Portugal in accordance with National legislation for the welfare of animals. Experiments were conducted in two 125 l cylindriconical tanks supplied with a continuous through-flow of oxygenated seawater at 20+1 °C using juvenile sea bream (25 g + 3 g) adapted for 1 week to the experimental conditions. One tank contained 8 untreated fish (control) and the other tank 8 cortisol treated fish and the end of experiments fish were removed form tanks, decapitated and the kidneys rapidly removed and place in RNAlater (Qiagen) at –20 °C. No mortality occurred in the control tank but 2 fish died in the cortisol treated tank. Keywords: other