Fecal glucocorticoid metabolites can be used as a stress indicator in bottlenose dolphins ().

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 (FGM).

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 1 day before and 2 days after the three stressful events.

RESULTS

We confirmed the validation of an extraction technique and an enzyme immunoassay to measure FGM 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 FGM than females, with a basal concentration of around 80 and 50 ng/g of dried feces, respectively.

CONCLUSION

Our study confirms that FGM 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.