Host: Primate Society of Japan
Cortisol, the primary glucocorticoid of human and non-human primates alike, is a key component to the physiological response to stress. This hormone is most commonly measured in blood serum or plasma, which not only involves venipuncture but may require additional stressful procedures such as capture and restraint that can easily confound the reliability of the assessment. Fortunately, stressful sample collection can be avoided by using alternative sample matrices such as urine, feces, or saliva (Davenport et al. 2006). Under stress, primates release the glucocorticoid steroid from the adrenal cortex into the systematic circulation, which binds to intracellular steroid receptors to produce transcriptional changes that function to restore homeostasis (Sapolsky et al. 2000). As an alternative to analyzing blood, in various animals stress has been evaluated by measuring glucocorticoid levels in saliva, urine, and feces (Queyras and Carosi 2004).
During recent decades, efforts have been made towards improving the housing and care of non-human primate in laboratories (Fagot et al. 2014). It has been documented well in both humans and animals, chronic stress can lead to a decline in health, both physically and psychologically. An animal's state of well-being can be measured in many ways, but an assessment of the animals' physiological and behavioral repertoire can give us a clearer picture of the status of its welfare. Indeed, many studies and reviews have been done to validate different methods of evaluating stress both in captive and non-captive conditions; however, not many studies have been done to evaluate stress in relatively natural-highly enriched settings compared to less enriched housing conditions. For the purpose of my study, I will be using non-invasive methods to quantify levels of stress by collecting fecal samples in both housing conditions. We hypothesize that animals living in a highly enriched environment, which have the ability to express a greater variety of behaviors, will subsequently have lower levels of cortisol, much closer to ones in free ranging or wild populations. Therefore, our findings might be useful for monitoring stress in many captive, and non-captive environments of primate populations alike, as well as promote non-invasive ways for assessing welfare.
