Meeting Abstract
Oxidative status has been implicated as playing a vital role in physiological processes and mediating life histories, as well as adaptive phenotypic adjustments to stressors. The antioxidant defense system is also highly plastic in vertebrates, and a significant amount of variation in individuals’ ability to resist oxidative stress as adults can be explained by the conditions experienced during development. Thus, the early life environment can cause a potentially beneficial alteration in the antioxidant system. At the same time, many studies have found differences in antioxidant levels and the amount of damage sustained between tissues in response to the same stressor. One possibility is that organisms prioritize protection of certain tissues over others, potentially those with greater impacts on fitness. We tested the hypothesis that male zebra finches (Taeniopygia guttata) exposed to a chronic mild stressor early in life will be better able to cope with a high stressor as adults, and will be characterized by upregulated antioxidant enzymes and decreased oxidative damage compared to the controls. Furthermore, we predict differences between tissue types, and expect reproductive tissue to have greater levels of protection than other tissues sampled. To test this hypothesis, we exposed juvenile male zebra finches to a prolonged mild heat stress (38° C) or control (22° C) temperature over 28 days. As adults, the males were then exposed to either a high heat stressor (42° C) or control temperature for 3 consecutive days. Four hours following the final treatment bout, birds were euthanized and the organs were collected. Using Western blots we quantified antioxidant enzyme levels [superoxide dismutase (SOD-1 and SOD-2) & glutathione peroxidase-1] and lipid oxidative damage (4-hydroxynonenal) in the liver and testes tissue.
