Techniques for collecting saliva from awake, unrestrained, adult monkeys for cortisol assay

Cortisol levels serve as an index of pituitary-adrenal activity in nonhuman primates. In adult monkeys, cortisol is normally measured in blood (typica lly requiring restraint or sedation) or urine (reflecting a state rather th an point estimate). In contrast, saliva collection is less invasive than dr awing blood and allows for repeated sampling within a short period of time. Although protocols exist for collecting saliva from young monkeys, these p rocedures are inadequate for awake, unrestrained adult animals. Our laborat ory has developed two methods for collecting saliva from adult rhesus monke ys: a "screen" method, which involves licking screen-covered gauze, and a " pole" method, which involves sucking and chewing on an attached rope. Twent y-three adult male rhesus monkeys were used to evaluate these two methods. After a period of adaptation, saliva samples were collected from 21 of 23 s ubjects. Saliva collection was faster with the pole than with the screen me thod (P < 0.01), but the pole method was not suitable for some animals beca use of their tendency to bite off the attached rope. An analysis of 19 sali va samples revealed a mean cortisol concentration of 0.84 mu g/dl (range 0. 27-1.77 mu g/dl). There was no statistically significant difference in cort isol value between methods used (P > 0.22). The influence of the flavoring on the cortisol assay was tested, and was found to have no significant effe ct (P > 0.28). Our results indicate that either technique can be used to sa fely collect saliva from unrestrained adult monkeys. Choice of technique wi ll depend on the proclivities of individual monkeys. Am. J. Primatol. 52:93 -99, 2000. (C) 2000 Wiley-Liss, Inc.