Meeting Abstract

6.2  Tuesday, Jan. 4  Effect of Diet and Training on Ketone Body Metabolism in Starlings OLSON, J.*; ALLPORT, K.; KEALEY, P.; MCWILLIAMS, S.; BAUCHINGER, U.; Villanova Un., PA; Villanova Un., PA; Villanova Un., PA; Un. of Rhode Island; Un. of Rhode Island john.olson@villanova.edu

Migratory birds are capable of performing long-distance flights, relying primarily on lipids. One consequence of high lipid catabolism is production of water-soluble ketone bodies, yet little is known about the extent to which ketone body metabolism changes as a function of diet and long-distance flight. This study tests the hypothesis that European Starlings fed a polyunsaturated fatty acid (PUFA) diet will exhibit higher capacities for both ketone body synthesis and mobilization (as indicated by HMG CoA-synthase and oxoacid CoA-transferase activities, resp.) than starlings fed a diet higher in monounsaturated fatty acid (MUFA). The effects will be more pronounced in trained birds. Twenty young European Starlings without prior migratory experience were caught, and placed on either a PUFA (51% 18:1, 26% 18:2) or MUFA (57% 18:1, 17% 18:2) diet. Half the birds in each diet were flown in a flight tunnel (AFAR, Univ. of Western Ontario) for increasingly longer times over a 15-d period. Organ samples were collected immediately after death, and enzyme activities were assayed spectrophotometrically at 30˚C using standard protocols. Contrary to predictions, diet and training did not affect the capacity for synthesis or use of ketone bodies in liver, kidney, or pectoralis muscle of European Starlings (p>0.20; 2-way ANOVA: with diet and training as factors). In contrast, the PUFA diet, but not training, increased oxoacid-CoA transferase activities in heart (Diet: F_1,18=7.87, p=0.013; Training: F_1,18=0.34, p=0.567; Diet*Training: F_1,18=0.42, p=0.527; 2-way ANOVA). As expected, liver is the key site of ketone body synthesis, and heart and kidney (in order) are key sites of use; maintenance of high capacity for ketone body catabolism in both of these organs is crucial to performing their ongoing roles.