Morfologia do tubo digestório aplicada à compreensão da dieta em quelônios da família Podocnemididae

Abstract

In the present study were used 15 specimens of each species, Podocnemis expansa, Podocnemis unifilis, Podocnemis sextuberculata, Podocnemis erythrocephala and Peltocephalus dumerilianus, aiming to define and characterize the morphology of their digestive tract. The biometric parameters were held in each specimen. The anatomical and histological procedure were carried out for further analysis of the organs of the digestive tract. The five species showed the esophageal mucosa divided and characterized by two distinct regions, the first with esophageal papillae and the second with longitudinal folds. The esophagus appeared as an aglandular organ with marked presence of mucous cells, goblet cells and secretory cells. The stomach in P. expansa, P. unifilis and P. erytrhocephala consists of two parts separated by a gastric evident constriction, the first portion is composed of massive cardic and fundic regions. Both were glandular regions, but characterized by the presence of goblet cells. In the anatomical position, the second part bends to the right just below the first one and is composed by a pyloric region well developed, and a large number of glands in the lamina propria. In P. sextuberculata the stomach showed a "J" shape and in Peltocephalus dumerilianus has a "C" shape. The small intestine (SI) in all species is a long, thin meandering tube with reticular folds in the proximal region, low longitudinal folds in a zigzag design in the medial region and a very evident high longitudinal fold with zigzag in the distal region. The organ is characterized by the presence of villi which appear different in each region of the SI. The large intestine (LI) in P. expansa, P. unifilis and P. erythrocephala begin with an enlarged and clear tube, the cecum, followed by a straight and tubular region, the colon/rectum. In P. sextuberculata and P. dumerilianus the large intestine is composed only by a tubular region, with a diameter larger than the SI. The GI has a large number of goblet cells. In all species difference was found between the length of the SI and LI. The SI is proportionally higher than the LI (p <0.0001). This work defines that the maintenance of these species of turtles in captivity need a diet that should be prepared separately for the adaptations of herbivores and another one for omnivory and carnivory.