Meeting Abstract
Snapping turtles (Chelydra serpentina) incubated as eggs under hypoxic (10% O2) conditions exhibit a decrease in growth rate independent of food intake compared to individuals incubated under normoxic (21% O2) conditions. Therefore we explored the effects of incubation environment on turtle digestive physiology by comparing pre- and postprandial metabolic rates, specific dynamic action (SDA), pancreatic function, and intestinal morphology and function of snapping turtles incubated as eggs under hypoxic and normoxic environments. We found incubation environment to have no significant effect on turtle standard metabolic rates, however hypoxia-incubated turtles experienced a 23% greater postprandial metabolic scope and a 45% greater SDA and SDA coefficient. We examine both fasted and fed turtles to explore the effects of incubation conditions on the form and function of digestive tissues. We found little difference in the mass of most organs between fasted and fed, and between hypoxic- and normoxic-incubated turtles, with the exception of the small intestine. Small intestinal mass did not differ as a function of incubation condition, but was significantly heavier for fed turtles. Fed turtles, regardless of incubation condition, possessed thinner serosa, whereas hypoxia-incubated turtles maintained enterocytes with larger volumes. Neither pancreatic trypsin nor amylase activities varied significantly among treatments. Similarly, the activities of the intestinal hydrolases aminopeptidase and maltase lack any significant differences among fed/fasted or hypoxia/normoxia treatments. Our only explanation for the reduced growth rate of the hypoxia-incubated turtles is that these turtles allocate more energy into the efforts of digestion, and hence less is channeled into growth.
