Abstract
Background:
Glucocorticoids increase in response to the hypothalamic–pituitary–adrenal axis stimulation, and their metabolites can be measured in dolphins’ feces.

Aim:
This study aimed to assess the welfare of bottlenose dolphins under human care by measuring fecal glucocorticoid metabolites.

Methods:
Our study consisted of measuring glucocorticoid metabolites concentration by enzyme immunoassay in fecal samples from five bottlenose dolphins housed in a dolphinarium. Dolphins were sampled once a month over a year, and one day before and two days after the three stressful events.

Results:
We confirmed the validation of an extraction technique and an enzyme immunoassay to measure fecal glucocorticoid metabolites and we observed an increase in their concentration after the stressful events, which provides a biological validation of this method. In parallel, we confirmed that males had a higher concentration of fecal glucocorticoid metabolites than females, with a basal concentration of around 80 and 50 ng/g of dried feces, respectively.

Conclusion:
Our study confirms that fecal glucocorticoid metabolites measurement is a relevant indicator of stress response in bottlenose dolphins under human care, although it needs to take into account the sex and reproductive status of the animals.

Key words: Bottlenose dolphin, Cortisol, Enzyme immunoassay, Feces, Stress