Evaluation of Glucocorticoid Faecal Monitoring as a Non-Invasive Assessment of Stress in Captive Crab-Eating Fox (Cerdocyoun thous) After ACTH Stimulation

Abstract

Blood sampling is a common method in biological research of domestic animals for studying hormone mechanisms. However, this approach can be stressful for wild species, and compromise research concerning animal welfare. The crab-eating fox (Cerdocyoun thous) is a medium-sized canid found in South America and a popular zoo species in that region. However, almost nothing is known of their biology or what factors impact captive welfare. Thus, a non-invasive method to measure adrenal activity and stress was developed for quantifying fecal glucocorticoids non-invasively in this species. The physiological relevance of the cortisol immunoassay was demonstrated by injection of exogenous ACTH into two males and one female, which led to a significant increase in fecal glucocorticoid metabolites within 24-48 h. From these findings we conclude that fecal samples can be used for the non-invasive assessment of adrenocortical status in crab-eating fox.

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

“…This is comparable to reported times found in silver foxes (Hovland et al 2017). However, others have found much longer delays (24 h to 48 h), when dealing with crab-eating, bat-eared and island foxes (Paz et al 2014;Le Roux et al 2016;Kozlowski et al 2020). Assessing delay times is an important part of a validation experiment, because they indicate when acute stressors are reflected in fGCM concentrations (Palme 2019).…”

“…The use of fGCMs has been validated as an indicator of adrenocortical activity in carnivores (e.g. Monfort et al 1998;Schatz and Palme 2001;Young et al 2004;Malmkvist et al 2011), and specifically in several fox species, including the silver fox (Vulpes vulpes; Hovland et al 2017), bat-eared fox (Otocyon megalotis; le Roux et al 2016), island fox (Urocyon littoralis; Kozlowski et al 2020) and the crab-eating fox (Cerdocyoun thous; Paz et al 2014). 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.…”

Quantifying long-term stress in brown bears with the hair cortisol concentration: a biomarker that may be confounded by rapid changes in response to capture and handling

“…This contrasts with the time scale of hours or days reflected by other matrices, including blood (serum or plasma), urine, saliva and faeces. Of these, faeces have also been widely used for the ‘non-invasive’ measurement of stress as reflected by its glucocorticoid levels ( Wasser et al , 2000 , 2011 ; Rodrigues da Paz et al , 2014 ). However, use of faecal glucocorticoid concentrations as an index of stress in brown bears has proved to be particularly challenging due to complex seasonal and dietary influences ( von der Ohe et al , 2004 ).…”