P2.178 Thursday, Jan. 5 Chronic stress alters stress-induced oxidative damage in domestic chickens (Gallus gallus) WHITLEY, B.N.*; TREIDEL, L.A.; BOWDEN, R.M.; HAUSSMANN, M.F.; Bucknell Univ.; Bucknell Univ.; Il. St. Univ.; Bucknell Univ. email@example.com
Glucocorticoid release in response to an acute stressor facilitates rapid energy expenditure by redirecting limited resources to essential functions, promoting short-term survival. However, repeated exposure to stress (i.e., chronic stress), can cause dysregulation of glucocorticoid secretion and abnormal glucocorticoid levels that can suppress growth, immune function, and reduce survival. We have previously shown that elevated glucocorticoids during an acute stress response accompany an increase in oxidative stress. Whether a similar oxidative stress response to an acute stressor occurs when an animal is simultaneously experiencing chronic stress is unknown. To test this, we exposed domestic chickens (Gallus gallus) to either control (C; n = 10) or chronic stress (S; n = 10) conditions. At twelve days post-hatch, all birds experienced an acute stress series (blood samples collected at <3, 20, and 45 min). Chronic stress birds were then exposed to 30 minute stressors five times a day for ten days. All birds underwent a second acute stress series after the chronic stress period. Oxidative damage and total antioxidant capacity were measured in all plasma samples. While there was no difference between C and S birds in oxidative stress levels before the initiation of the chronic stress period, after ten days of chronic stress, S birds had a decreased oxidative stress response compared to the C birds. Chronically stressed birds may have lower corticosterone levels during an acute stress response resulting in decreased oxidative stress. Alternatively, if chronically stressed birds have elevated baseline corticosterone there may be a concomitant protective increase in antioxidant defenses, mitigating the rise in oxidative stress in response to an acute stressor.