Beyond Glucocorticoids: Integrating Dehydroepiandrosterone (DHEA) into Animal Welfare Research

Abstract

Animal welfare researchers are committed to identifying novel measures for enhancing the quality of life of individual animals. Recently, welfare scientists have emphasized the need for tracking multiple indicators of an animal’s behavioral, emotional and mental health. Researchers are currently focused on integrating non-invasive physiological biomarkers to gain insight into an individual’s welfare status. Most commonly, the animal welfare community has analyzed glucocorticoid hormones and their metabolites as a measure of stress. While glucocorticoids provide valuable information about hypothalamic–pituitary–adrenal (HPA) axis activity, there are limitations to utilizing these hormones as the sole measure of long-term stress and welfare. Other biomarkers, such as dehydroepiandrosterone and its sulfate ester—collectively referred to as DHEA(S)—help provide a more complete picture of HPA activity. DHEA(S) counteracts the effects glucocorticoids by having anti-aging, immune-enhancing and neuroprotective properties. Recent studies have examined the ratio of glucocorticoids to DHEA(S) as a way to better understand how the HPA axis is functioning. There is evidence that this ratio serves as an indicator of immune function, mental health, cognitive performance and overall welfare. We review studies that employed the glucocorticoid:DHEA(S) ratio, outline methodological considerations and discuss how researchers can integrate glucocorticoids, DHEA(S) and the glucocorticoid:DHEA(S) ratio into welfare assessments.

Níveis de Cortisol: Impactos sobre a Saúde Mental e a Imunidade / Cortisol Levels: Impacts on Mental Health and Immunity

“…Sabe-se que os glicocorticoides, tal como o cortisol, quando elevado, inibe a liberação de hormônios que participam da produção dos esteróides anabolizantes. Esses atuam no crescimento, cura e na reprodução (WHITHAM et al, 2020).…”

“…Evidentemente, os prejuízos do aumento do cortisol no âmbito cognitivo, incluindo memória e aprendizagem, pode também afetar os sistemas de feedback negativo (WHITHAM et al, 2020).…”

Hair Cortisol, Testosterone, Dehydroepiandrosterone Sulfate and Their Ratios in Stallions as a Retrospective Measure of Hypothalamic–Pituitary–Adrenal and Hypothalamic–Pituitary–Gonadal Axes Activity: Exploring the Influence of Seasonality

“…Recently, there has been growing attention on those endocrine systems that interfere with each other in complex dynamic ways [ 2 ], such as the hypothalamic–pituitary–gonadal (HPG) and hypothalamic–pituitary–adrenal (HPA) axis. Hence, assessing simultaneously hormones that are thought to co-regulate to each other, such as those secreted by HPA and HPG activation, would be postulated as a better approach to physiological stress measurements [ 2 , 3 ].…”

“…Cortisol (C), the main glucocorticoid in mammals [ 4 , 5 ], is commonly used as a physiological indicator of stress, since it is secreted after the activation of the HPA axis in response to a situation in which homeostasis is threatened by the actions of various external or internal stressors [ 5 , 6 ]. Additionally, with the activation of the HPA axis, other components, such as dehydroepiandrosterone (DHEA) and its sulfate ester (DHEA-S), are released into bloodstream [ 3 ]. Both DHEA and DHEA-S have been characterized as glucocorticoid antagonists, and are considered as indicators of resilience, because of their anti-aging, immune-enhancing and neuroprotective functions [ 3 ].…”

“…Additionally, with the activation of the HPA axis, other components, such as dehydroepiandrosterone (DHEA) and its sulfate ester (DHEA-S), are released into bloodstream [ 3 ]. Both DHEA and DHEA-S have been characterized as glucocorticoid antagonists, and are considered as indicators of resilience, because of their anti-aging, immune-enhancing and neuroprotective functions [ 3 ]. Testosterone (T) is the main sexual steroid in males and has been used as a stress indicator, since this hormone is negatively influenced by stressful living environments, impacting reproductive performance, growth rate, and immunity [ 7 ].…”