Meeting Abstract

24.1  Friday, Jan. 4  Digestive physiological differences between alligators and crocodiles: Are crocodilians just meat eaters? TRACY, Christopher R.*; MCWHORTER, Todd J.; MANOLIS, S. Charlie; WEBB, Grahame J. W.; CHRISTIAN, Keith A.; Charles Darwin University; Murdoch University; Wildlife Management International; Wildlife Management International; Charles Darwin University chris.tracy@cdu.edu.au

Some of the New World crocodilians (alligators and caimen) appear to do reasonably well on artificial diets with high plant components (e.g. corn meal), but crocodiles consistently do poorly. We measured activity of membrane bound intestinal enzymes and looked at efficiency of uptake via mediated and paracellular (passive) pathways in American alligators (Alligator mississippiensis) and saltwater crocodiles (Crocodylus porosus) as a preliminary exploration of whether their physiological differences in digestive ability might help explain the differences in crocodilian well-being on artificial diets. We found that alligators had much higher activities of dissacharidases than crocodiles, and different proportions of nutrient uptake via mediated vs. paracellular pathways that suggest that alligators may absorb sugars more efficiently than crocodiles. Together, this suggests that a more comprehensive comparison of digestive physiology between these two lineages may reveal that there is a physiological explanation for why the two groups respond so differently to plant-based diets.