Abstract
The metabolic profiles of selected tissues were analyzed in hatchlings of the Amazonian freshwater turtles Podocnemis expansa, P. unifilis and P. sextuberculata. Metabolic design in these species was judged based on the key enzymes of energy metabolism, with special emphasis on carbohydrate, lipid, amino acid and ketone body metabolism. All species showed a high glycolytic potential in all sampled tissues. Based on low levels of hexokinase, glycogen may be an important fuel for these species. The high lactate dehydrogenase activity in the liver may play a significant role in carbohydrate catabolism, possibly during diving. Oxidative metabolism in P. sextuberculata appears to be designed for the use of lipids, amino acids and ketone bodies. The maximal activities of 3-hydroxyacyl-CoA dehydrogenase, malate dehydrogenase, glutamine dehydrogenase, alanine aminotransferase and succinyl-CoA keto transferase display high aerobic potential, especially in muscle and liver tissues of this species. Although amino acids and ketone bodies may be important fuels for oxidative metabolism, carbohydrates and lipids are the major fuels used by P. expansa and P. unifilis. Our results are consistent with the food habits and lifestyle of Amazonian freshwater turtles. The metabolic design, based on enzyme activities, suggests that hatchlings of P. unifilis and P. expansa are predominately herbivorous, whereas P. sextuberculata rely on a mixed diet of animal matter and vegetation.
Highlights
It has been proposed that the freshwater turtles Podocnemis expansa and P. unifilis are primarily herbivorous (Alho et al, 1979; Best, 1984)
In an attempt to provide information for future work in conservation and wildlife management of Amazonian freshwater turtle species, we supply a general picture of the metabolic framework and address whether the metabolic preference of these animals is related to their diet and other aspects of life history
The present study examined the activity of enzymes of intermediary metabolism in four tissues: muscle, liver, heart and brain of three Amazonian freshwater turtles: P. expansa, P. unifilis and P. sextuberculata
Summary
It has been proposed that the freshwater turtles Podocnemis expansa and P. unifilis are primarily herbivorous (Alho et al, 1979; Best, 1984). Fachin-Teran et al (1995) studying the natural populations of freshwater chelonian from Guaporé River (Southwestern of Amazonia) concluded that both adult and juvenile P. expansa and P. unifilis feed preferentially on plant material. Podocnemis sextuberculata is a small freshwater species in the Amazon Thompson et al (1999) determined that protein catabolism might represent a substantial proportion of energy cost during development in an omnivorous Australian short-necked turtle, Emydura macquarii. Amino acid metabolism oxidation constitutes an important contribution to energy demand during early development of omnivorous or carnivorous species. In an attempt to provide information for future work in conservation and wildlife management of Amazonian freshwater turtle species, we supply a general picture of the metabolic framework and address whether the metabolic preference of these animals is related to their diet and other aspects of life history. The present study examined the activity of enzymes of intermediary metabolism in four tissues: muscle, liver, heart and brain of three Amazonian freshwater turtles: P. expansa, P. The present study examined the activity of enzymes of intermediary metabolism in four tissues: muscle, liver, heart and brain of three Amazonian freshwater turtles: P. expansa, P. unifilis and P. sextuberculata
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
