Meeting Abstract
A high metabolic output is necessary for birds to complete long distance flights, however this high metabolism produces reactive oxygen species that have the potential to cause oxidative damage to cells and tissues if unmediated. We investigated how the oxidative defense system responded to dietary fatty acid composition and antioxidant supplementation as well as to exercise. European starlings (Sturnus vulgaris) were flown in a wind tunnel for on average 15 hours over 15 days. Trained birds (and paired sedentary birds) were fed one of four diets composed of either a high or low polyunsaturated fatty acid (PUFA, 18:2n-6) and a high or low concentration of the antioxidant, anthocyanin. Endurance training stressed the antioxidant defense system, as plasma oxidative capacity (Oxy-adsorbant test) was lowest in exercised birds during training immediately before and after a 3 hour experimental flight compared to pre-training and at sacrifice 2 days post-training (p<0.05, RMANOVA). Oxy did not change among sedentary birds (p=0.19) nor in accordance with diets (neither in controls p=0.83 nor trained birds p=0.13). Plasma oxidative damage (dROMs test) was unchanged in sedentary birds (p=0.50), however damage was highest in trained birds immediately before a 3 hour flight compared to post-flight and pre-training (p<0.05). Red blood cell glutathione peroxidase activity was greater in all trained diet groups (from 13-26%) immediately post-flight with the greatest enzyme activity in the high antioxidant groups. The antioxidant defense system demonstrates flexibility in response to elements important during migration, notably exercise and nutrition.
