Salivary alpha-amylase enzyme as a non-invasive biomarker of acute stress in Japanese macaques (Macaca fuscata)

Abstract

Human studies have revealed salivary alpha-amylase (sAA) enzyme levels are positively correlated with the release of the hormone norepinephrine, allowing sAA to act as a biomarker for sympathetic nervous system (SNS) activity. The SNS is associated with the fight-or-flight response and is a separate but parallel stress response system to the hypothalamic-pituitary-adrenal (HPA) axis. Recent non-human primate studies have made progress in using sAA as an additional physiological stress marker. However, there are currently no published reports of sAA validation as an acute stress response marker in Japanese macaques. Furthermore, saliva collection could prove itself to be stressful for the monkey. Consequently, developing a non-invasive method for cooperative saliva collection between the researcher and monkey is not only necessary for accurate data collection but is also ethically sound. Therefore, this study has a two-fold aim: [1] non-invasively collect saliva with the monkey’s cooperation and [2] validate sAA as a biomarker of acute stress in M. fuscata. Validation of sAA enzyme as an acute biomarker in Japanese macaques could provide a useful tool for future research questions as well as practical uses in animal welfare. I will discuss developing a methodology for saliva collection, current findings, and other recent research activities.