Meeting Abstract
Among snakes exists an adaptive relationship between feeding habits and the regulation of intestinal performance with feeding and fasting. Snakes that feed relatively frequently experience modest changes in intestinal performance from meal to meal, whereas infrequently feeding snakes downregulate intestinal performance upon the completion of digestion and thus rapidly upregulate performance with feeding. We tested this hypothesis by comparing the postfeeding responses in intestinal function and morphology between the frequently feeding Asian vine snake (Ahaetulla prasina) and the infrequently feeding prairie rattlesnake (Crotalus viridis). With feeding, vine snakes experience a 50% and 43% increase in pancreatic and small intestinal mass, respectively, whereas rattlesnakes exhibited 50-160% increase in the mass of the liver, pancreas, small intestine, and large intestine. Vine snakes experience no significant change with feeding in mucosal thickness or in the volume of intestinal enterocytes. Mucosal thickness and enterocyte volume increased by a respective 80% and 115% with feeding for the rattlesnake. Pancreatic trypsin and intestinal aminopeptidase and maltase activities did not vary with feeding for the vine snake, though the intestinal hydrolases increased postprandially for the rattlesnake, generating a 2- and 3.4-fold increase in total intestinal capacity for maltase and aminopeptidase activity. As predicted based on their feeding habits, these snakes exhibit the observed dichotomy in the regulation of digestive performance, with the infrequently feeding rattlesnakes experiencing wide regulation of intestinal performance, and the frequently feeding vine snakes exhibiting much more narrow responses.
