30.1 Thursday, Jan. 5 The effects of high carbohydrate versus high protein diet on body composition, endurance flight capacity and fuel mixture in a migratory songbird GUGLIELMO, C.G.*; GERSON, A.R.; Univ. of Western Ontario; Univ. of Western Ontario email@example.com
Migratory birds eat a wide variety of diets, and some switch diets during migration. A typical pattern is for insectivorous birds to switch to fruits when they are abundant. Previous studies, based on plasma metabolite analysis, suggest that diet may influence the mixture of fuels in flight; eating high protein insects may increase the use of protein and eating high carbohydrate fruits may enhance fat metabolism. High carbohydrate diets also typically increase body fatness and refueling rate. We acclimated yellow-rumped warblers (Dendroica coronata) to synthetic diets containing dry mass ratios of either 60:15:10 or 15:60:10 carbohydrate:protein:fat while they were in fall and spring migratory states. Body composition was measured non-invasively by quantitative magnetic resonance and endurance flight performance was tested at 7.8 m/sec flight speed in a climatic wind tunnel at 15 C and 70% RH. High carbohydrate diet increased body mass by 8% and body fatness by 50%, but did not affect lean mass. The likelihood of completing a flight of greater than 45 min was doubled by the high carbohydrate diet. Voluntary flight duration lasted up to six hours and was not affected by fat load, but was nearly double in the high carbohydrate group. The percent of energy derived from the catabolism of lean mass (protein) was negatively related to flight duration, but not diet. Our results indicate that dietary variation can influence body composition and endurance flight performance, but does not affect fuel mixture.