Estudo comparativo da morfologia dos intestinos delgado e grosso do morcego frugívoro Artibeus planirostris (Chiroptera, Phyllostomidae, Stenodermatinae) e do morcego hematófago Diphylla ecaudata (Chiroptera, Phyllostomidae, Desmodontinae)

Abstract

Although bats are associated with the transmission of rabies virus, they are also recognized as having the most diverse eating habits among mammals, especially the Phyllostomidae family. Thus, specializations to such diverse eating habits require morphological adaptations in the digestive organs, so that knowing its morphology allows a better understanding of the digestive physiology of these animals and provides subsidies for conservation efforts. However, the frugivore Artibeus planirostris and the hematophagous Diphylla ecaudata lack information about the complete morphology of the digestive tract. Thus, this study aimed to analyze and compare the morphological and morphometric aspects of its small and large intestines. For this, five animals of each species were captured, euthanized, and their intestines were removed, processed and stained with Hematoxylin-Eosin (HE) and Periodic Acid Schiff (PAS). Morphometric measurements of the tissue structures of these organs were obtained, and the results were submitted to the normality test (Shapiro-Wilk) and compared to the t test, considering a significance level of 5% (p<0.05). Macroscopically there was no distinction between the small and large intestines. In addition, few aspects allowed distinguishing the three regions of the small intestine for both species. A. planirostris presented villi with an approximate height of 1,231 μm, few Brunner glands in the duodenum and external muscular layer thicker than the internal one. The large intestine presented circular folds with many intestinal glands, meaning an intense activity of water absorption. While D. ecaudata showed a lower height of villi (527 μm). The large intestine, on the other hand, had a smaller number of intestinal glands, and in both small and large intestines, the wall was significantly thinner when compared to A. planirostris, indicating an adaptation to the hematophagous habit. Therefore, there were remarkable differences between the intestines of these two species, a direct reflection of adaptations to the different diets, which contributes to the evolutionary success of the bats, allowing them to reduce the retention time of the food in the digestive tube, decreasing body weight during the flight.