Egg cortisol exposure enhances fearfulness in larvae and juvenile rainbow trout
Résumé
We investigated the effects of an early boost of cortisol exposure in
rainbow trout (Oncorhynchus mykiss) eggs during fertilisation on subsequent
behavioural responses when exposed to a sudden stimulus in larvae
and juveniles. At 55 d post-fertilisation (dpf), treatment had no effect on
high accelerations occurring after a sudden event. At 146 dpf, these high
accelerations were more frequent in cortisol-treated fish than in controls.
At 146 dpf also, swimming activity was increased in cortisol-treated fish
both before and after the sudden stimulus. This study underlines the
important behavioural modifications in both larvae and juveniles, linked
to a change in the surrounding environment of the embryo. Indeed, fish
exposed to cortisol as eggs showed a higher level of fearfulness later in life.
Our findings are of major interest for stress management in an aquaculture
context and also allow for a better understanding of the long-lasting
effects of a permanent and/or acute stress – mediated by cortisol – that
could be encountered by females, affecting population’s life history
trajectory.