Comparative study of the spermatogenic process on vampire bats Desmodus rotundus and Diphylla ecaudata (Chiroptera: Phyllostomidae)
Vampire bats, Reproductive biology, Testicular morphometry, Spermatogenesis.
The vampire bats are the only mammals that feeds exclusively on the blood of mammals or birds. Due to this peculiarity, and your relationship with the transmission of the rabies virus, they arouse great attention and curiosities, being necessary the development of conservation measures that will enable the rational control of these species. To this end, it is essential that their reproductive cycles are known. Therefore, we aimed to describe the testicular activity of the species Desmodus rotundus and Diphylla ecaudata, along different periods of the year. After obtaining licenses by the ICMBio and CEUA/UFRN, the animals were collected in Lajes-RN and transported to Natal-RN. After euthanasia procedures, their testes were processed histologically for embedding in historesin for morphological and morphometrical analyses under light microscopy, and for analysis of cellular ultrastructure under transmission electron microscopy. The testicular morphometry was made by capturing images of histological slides and using the software Image-Pro Plus®. Considering the two seasons, D. rotundus presented gonadosomatic index (GSI) 0.51% and the seminiferous tubules represented around 94% of testicular parenchyma, the rest being represented by the intertubule. The seminiferous tubules were represented by about 20% of lumen, 70% of seminiferous epithelium and 4% tunica propria. The tubular diameter and the height of the seminiferous epithelium showed averages of 207μm and 55μm, respectively. The average length of the seminiferous tubules per gram of testis was 28m and the average tubulesomatic index (TSI) was 0.55%. D. ecaudata presented 0.73% of GSI and the seminiferous tubules also represented around 94% of testicular parenchyma. The seminiferous tubules were represented by about 18% of lumen, 74% of seminiferous epithelium and 2% of tunica propria. The tubular diameter and the height of the seminiferous epithelium showed averages of 195μm and 51μm, respectively. The tubular length per gram of testis was 31m and TSI was 0.42%. Considering both seasons evaluated, the Leydig cells of D. rotundus presented averages of nuclear diameter, Leydigosomatic index and number per gram of testis of 15.62μm, 0.02% and 45.22x105 cells, respectively. In D. ecaudata, these values in the dry season were respectively, 17.45%, 0.02% and 24.05x105 cells. The results obtained so far are similar between the species evaluated, as well in other species of bats and other mammals. It is necessary to estimate the indexes of sperm production to determine the patterns of spermatogenesis of the species in this study.