Prey cortisol affects the usefulness of fecal glucocorticoid metabolite concentration as an indicator of stress in a carnivore

Abstract

Prey cortisol affects the usefulness of fecal glucocorticoid metabolite concentration as an indicator of stress in a carnivorefemales, compared to controls. In addition, fecal metabolite concentrations in non-treatment samples were higher for females (22.2 ± 3.3 ng g -1 , mean ± SE) than males (13.3 ± 1.5 ng g -1 ), suggesting female Arctic foxes may have higher baseline cortisol concentrations or females may be more sensitive to captivity or relocation. These results indicate that prey cortisol can influence measurement of glucocorticoid metabolites in carnivore feces and suggest caution may be needed when interpreting such measurements in wild carnivores.

Fecal glucocorticoid metabolites as an indicator of adrenocortical activity in Arctic foxes (Vulpes lagopus) and recommendations for future studies

“…A recent study (McDonald et al 2018) used a cortisol radioimmunoassay for measuring fGCMs in Arctic foxes. Despite adding extremely high amounts of cortisol to the fox diet, the measured fGCM levels were only moderately increased afterwards, suggesting that the applied cortisol radioimmunoassay may not be suitable for Arctic foxes.…”

“…Because of significant differences between species in excreted fGCMs (Palme 2019) and in gut passage time, it is necessary to validate FGM measures for each species and assay. Although fecal GCMs have recently been used in studies of stress in both wild (McDonald et al 2018) and farmed Arctic foxes (Sanson et al 2005), no successful validation of the method was carried out in these studies. A physiological validation is an experimental process, where animals are injected with synthetic ACTH, thereby stimulating the release of glucocorticoids (Touma and Palme 2005).…”

Changes in Fecal Glucocorticoid Metabolites in Captive Coyotes (Canis latrans): Influence of Gender, Time, and Reproductive Status

“…Glucocorticoids (GC) and their glucocorticoid metabolites (GCMs), including cortisol and corticosterone, are hormones involved in regulating energy [1] and assist most Animals 2023, 13, 3596 2 of 15 mammals [2], including carnivores [3][4][5][6][7], to overcome stressful or metabolic changing situations [2,8,9]. Stress is a cascade of neurological, hormonal, and immunological responses to changes in the environment [10] and includes daily responses to metabolic situations such as digestion and sleeping, as well as long-term challenges such as reproduction [9].…”