Faecal Cortisol Metabolites as an Indicator of Adrenocortical Activity in Farmed Blue Foxes

• Published in: Animals
• Main Authors: Ojala, Eeva A., Kurkilahti, Mika, Hovland, Anne Lene, Palme, Rupert, Mononen, Jaakko
• Format: Text
• Language: English
• Published: MDPI 2021
• Subjects: Article; Eia; Vulpes lagopus
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8470140/; http://www.ncbi.nlm.nih.gov/pubmed/34573597; https://doi.org/10.3390/ani11092631

SIMPLE SUMMARY: The measurement of faecal cortisol metabolites (FCMs) is increasingly used to monitor physiological stress responses in different animal species. Before this method is applied in coming stress- and welfare-related studies of farmed blue foxes (Vulpes lagopus), a species-specific validation is first required. In the current study, a 5α-pregnane-3ß,11ß,21-triol-20-one enzyme immunoassay was found suited to measure FCMs and thus hypothalamus–pituitary–adrenal (HPA) axis activity in farmed blue foxes. FCMs can therefore serve as a valid indicator of stress in future welfare studies of blue foxes. ABSTRACT: Welfare studies of blue foxes would benefit from a measurement of faecal cortisol metabolites (FCMs) as a non-invasive, physiological stress parameter reflecting hypothalamus–pituitary–adrenal (HPA) axis activity. Before implementation, a species-specific validation of such a method is required. Therefore, we conducted a physiological validation of an enzyme immunoassay (EIA) to measure FCMs in blue foxes. Twenty individuals (nine males and eleven females) were injected with synthetic adrenocorticotrophic hormone (ACTH) and faecal samples were collected every third h for two days. The FCM baseline levels were assessed based on the first sampling day (control period, 144 samples), followed by the ACTH injection and the second day of sampling (treatment period, 122 samples). FCMs were analysed with a 5α-pregnane-3ß,11ß,21-triol-20-one EIA. We compared the estimated mean FCM concentrations of the treatment samples to the baseline average. All samples for the two periods were collected at the same time of the day, which enabled to test the data also with an hourly pairwise comparison. With the two statistical approaches, we tested whether a possible diurnal fluctuation in the FCM concentrations affected the interpretation of the results. Compared to the baseline levels, both approaches showed 2.4–3.2 times higher concentrations on time points sampled 8–14 h after the ACTH injection (p < 0.05). The ...