Metabolism of Chrysemys picta During Fasting and During Cold Torpor

Abstract

Chrysemys picta Schneider, a fresh water turtle, is capable of withstanding lengthy periods of fasting and cold torpor. An investigation was made of the biochemical differences between specimens in cold torpor, 4° ± 2°C, for 4–8 weeks, fasting specimens at room temperature, 22° ± 4°C, for 6–8 weeks and fed controls at the same room temperatures. Respiratory quotients of controls, torpid and fasting turtles were: 0.814 ± 0.019, 0.744 ± 0.029, 0.719 ± 0.025. The specimens in cold torpor showed marked decreases in oxygen consumption, heat production and metabolic rate. The fasted turtles showed characteristic biochemical properties of decreased liver total fatty acids, decreased blood glucose, and increased urine uric acid levels. The specimens in cold torpor had increased liver total fatty acids, a significant increase in liver glycogenolysis and increased urine uric acid levels. It was concluded that fundamental metabolic and biochemical differences exist between turtles in cold torpor and fasting turtles, and that both experimental types differ from the fed controls.