Meeting Abstract
Damage created by the leak of electrons from the electron transport chain and formation of reactive oxygen species (ROS) has been implicated as a possible mechanism for the tradeoff between energetically demanding life-history traits such as reproduction and longevity, yet this implication is based on the assumption that there is a positive correlation between ROS production and energy expenditure. Evaluation of mitochondrial bioenergetics suggests that this assumption is incorrect. To confirm this, we evaluated the relationship between energy expenditure and oxidative damage, as a proxy for ROS production, in the House Finch (Haemorhous mexicanus). We also evaluated the relationship between oxidative damage in blood and organs, as damage in the blood is commonly assumed to reflect processes occurring throughout the body. Finches were assigned to 1 of 3 cage sizes to simulate differences in activity and relative energy expenditure. Precise differences in energy expenditure are being evaluated using the doubly labeled water method. After at least 2 weeks in assigned cages, the birds were scarified and liver, pectoralis, and blood were collected. The relative concentration of protein carbonyls in each tissue was evaluated. Our results indicated that there is no correlation between oxidative damage to proteins and cage size for any of the tissues evaluated. In addition, we found no correlation between oxidative damage to proteins in the blood and oxidative damage to muscle or liver. Additional measures of oxidative damage will be presented. Our findings indicate that the assumptions that energy expenditure and oxidative damage are positively correlated and that blood accurately reflects oxidative damage throughout the body are both incorrect.
