Metabolic fuel selection: Exercise and cold exposure

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This research deals with the ability of animals to survive in the cold and to perform long-distance migrations. The first project investigates how fish cope with changes in temperature and environmental contaminants like PCBs. Cold-blooded animals must be able to modify cell membranes to ensure the maintenance of normal metabolism as their body temperature fluctuates. Because many PCBs accumulate within membranes, it is particularly important to know whether these toxins interfere with the life-saving changes in membranes taking place during acclimation to different temperatures. The second project investigates how migrant birds manage their energy reserves during cold exposure and endurance exercise. Long-distance migrant birds have a remarkable ability to survive in very cold environments and to use fat stores during locomotion. However, the mechanisms used by these amazing athletes to cope with cold and to travel non-stop for thousands of kilometers have not been elucidated. We will determine how Canada geese protect uninsulated parts of their body from freezing in the winter. We will carry out experiments to test whether they flood their legs with warm blood at regular intervals and possess antifreeze proteins in their feet to survive in the cold. Newly hatched geese normally imprint on their mother, but they can also do so on a human surrogate parent. We will imprint young geese on the pilot of an ultralight paramotor and train them to follow it in free flight. Trained adult geese (4 kg) will be fitted with a 150-g backpack containing an automated device able to monitor their use of metabolic fuels. For the first time, this robot will help us to measure how they transfer energy from fat reserves to working muscles at record rates during flight. This research has significant implications for: 1) understanding how fish will cope with global warming in the presence of environmental contaminants, 2) formulating new policies for wildlife conservation to help endangered migrant bird species to manage energy, and 3) finding new ways to improve the performance of human athletes.