Meeting Abstract
While it is known that chronic exposure to noxious stimuli can result in detrimental effects, we still lack a complete understanding of how specific factors influence the transition from the beneficial, acute response into the chronic, damaging one. In this study, we used house sparrows (Passer domesticus) to test a) whether brief recovery periods can relieve this wear and tear, and b) whether these periods influence responses to subsequent bouts of chronic stress. Birds were randomly assigned to one of three treatment groups that were permitted either 0 hours, 24 hours, or 72 hours of recovery following 4 days of a repeated stress protocol. Birds were then subjected to an additional 4 days of a repeated stress protocol. Blood samples were taken prior to the start of the initial stress protocol, after the recovery period, and at the end of the final stress protocol and assayed for baseline, stress-induced, negative feedback strength, and maximum capacity of corticosterone (CORT). Video samples were also taken to quantify changes in the neophobic response. We predicted that birds that were permitted longer periods of recovery would regain negative feedback strength and capacity, and maintain their neophobic responses. Changes in baseline and maximum CORT capacity were independent of recovery period throughout the entire experiment. Stress-induced CORT was reduced most dramatically for the 24-hour recovery group. Negative feedback strength unexpectedly remained the same for the 24-hour group, however was attenuated for the 0 and 72-hour groups over the first two sample points. Neophobia increased nonsignificantly with increasing recovery periods. In sum, these data suggest that brief recovery periods can marginally influence subsequent stress physiology and behavior.
