P3.176 Sunday, Jan. 6 A meta-analytic approach to comparing indices of stress in vertebrates: Does heterophil:lymphocyte ratio reveal similar degrees of stress as circulating corticosterone concentration? GOESSLING, J.M.*; MENDONÇA, M.T.; WILSON, A.E.; Auburn Univ.; Auburn Univ.; Auburn Univ. firstname.lastname@example.org
While a suite of assays is available to biologists interested in measuring physiological stress, there is not a consensus as to the most reliable biomarker indicating an individual is experiencing an environmental stressor, especially on a chronic basis. Additionally there are many constraints (i.e., timing, effort, and cost) that impact which measure(s) of stress to use. We used meta-analysis to synthesize and compare available data associated with the response of two commonly used assays of physiological stress: heterophil:lymphocyte ratio (H/L) and circulating glucocorticoid concentration (GC). Because the studies where both measures were obtained centered in groups (i.e., birds and reptiles) where the primary GC is corticosterone (CORT), we only analyzed studies using those species which use CORT as the primary GC. We compared paired values of H/L and CORT from control (i.e., “unstressed”) and treatment (i.e., “stressed”) populations to test for differences between the ability of the two measures to reliably indicate stress. Our analysis included two taxonomic classes (birds and reptiles) and 14 species across a broad range of stress types (e.g., food restriction, temperature stress, increased density, etc). In general, H/L and CORT responses to stress were similar and no differences between the stress indices were observed as a result of class, species, captivity status, or stress treatment type. Thus, we support the use of either measure as a reliable biomarker of stress, although H/L may represent a more practical assay due to logistical considerations.