Meeting Abstract

P3.90  Tuesday, Jan. 6  Maintenance of digestive performance is ontogenetically stable for the American alligator GIAMBRONE, T.P.; LIGNOT, J.-H.; SECOR, S.M.; FREDERICK, J.*; University of Alabama; CNRS, DEPE, Strasbourg; University of Alabama; University of Alabama ssecor@biology.as.ua.edu

We investigated whether the American alligator (Alligator mississippiensis) experiences ontogenetic shifts in the magnitude of their postprandial metabolism and in the regulation of gastrointestinal morphology and function with fasting and feeding. Neonate (38-62 g), juvenile (740-989 g), and subadult (2340-5240 g) alligators all experienced a rapid postprandial increase in metabolic rate following rodent meals weighing 5% of body mass that peaked at 2.73, 2.92, and 3.64-fold of standard metabolic rate, respectively, at 36 or 48 hours postfeeding. Specific dynamic action, independent of body mass, was significantly higher for subadult alligators. We observed no significant postprandial change in the mass of the small intestine or any other organ for neonate, juvenile, and subadult alligators. Alligators also did not exhibit any postprandial change in intestinal microvillus length. Gastric pH and the pH of other sites of the GI tract did not differ between fasted and fed alligators. For each age class, feeding did not generate any significant change in pancreatic trypsin activity or total pancreatic typsin capacity. For the three age classes, small intestinal nutrient uptake rates seldom differed between fasted and fed alligators, and there was no postprandial change for each age in intestinal nutrient uptake capacity. Independent of alligator body mass, intestinal mass and uptake rates and capacities decreased with age. Similar to species of frequently feeding reptiles, alligators maintain gastrointestinal form and function between bouts of fasting and feeding.