The Effect of Chronic Psychological Stress on the Blood Chemistry of European Starlings (Sturnus Vulgaris).
- We applied chronic psychological stress by exposing European starlings (Sturnus vulgaris) to a previously validated chronic stress protocol (CSP) consisting of 4 different randomly applied stressors per day. Experimental design consisted of a 21 day CSP (CSP1), a 60 day recovery (R1), a second 14 day CSP (CSP2), and a second 30 day recovery (R2). Body weight decreased approximately 5% during CSP1,... read morebut overshot to 5-10% above initial body weight during R1. To investigate underlying mechanisms, we periodically measured corticosterone and 12 biochemical analytes, including aspartate aminotransferase (AST), creatinine kinase (CK), bile acids (BA), total protein (TP), albumin (ALB), globulin (GLOB), glucose (GLU), uric acid (UA), calcium (CA++), phosphorus (PHOS), potassium (K+), and sodium (NA+). AST and CK increased at the beginning of CSP1, suggesting muscle breakdown. Additionally, decreases in ALB and TP paired with stable UA, but no associated change in GLU, suggested protein breakdown as a secondary energy source. Changes in blood parameters that occurred during CSP1 did not recover during R1. During CSP2 and R2, weight loss and gain occurred in different proportions. CSP2 produced an approximate 15% decrease in body weight and only re-gained 5% body weight during R2, but returned to pre-CSP1 weight. Corticosterone increased during CSP2 but not during CSP1.read less