Ocorrência da espécie e estimativa de população folicular ovariana de Bradypus variegatus (Shinz 1825) nos municípios de Pacajá-PA e Araguaína-TO

Abstract

Bradypus variegatus Schinz (1825), popularly known as common sloth, is a wild mammal of wide distribution, extending from Central America to South America. However, studies on the reproductive biology of these animals are scarce, which are necessary to assist in basic and applied research for effective actions of conservation medicine. In addition, the lack of information on the occurrence of this species in the state of Tocantins makes it impossible to carry out actions in wildlife management. Thus, the objective of this work was to survey the occurrence of the species in the region of Legal Amazon, and to describe and estimate the population of ovarian follicles of B. variegatus. In order to study the occurrence of the B. variegatus species, an informational survey was carried out with the CETAS de Araguaína - TO, a questionnaire survey, and walks in the microregions of the state of Tocantins and Pará.For the study of morphology and estimation of ovarian follicles, 4 ovaries were used which were histologically processed, stained in HE, Masson's Trichrome and PASHematoxinin, and analyzed under a light microscope at 400x. Descriptive and chi-square statistics were performed at 5% probability. Eight specimens were observed, 1 in Pará and 7 in Tocantins. Regarding the results of the questionnaire on the occurrence of the species, 44% of respondents stated that currently there is difficulty in visualizing the species, consequent to anthropic actions. On the ovarian morphology, the analysis showed that the ovaries presented cortex, where ovarian follicles were found in different stages of development: primordial, primary, secondary and tertiary, dispersed in dense unformed conjunctive; and the medullary region, internal, formed by loose vascular connective tissue. In B. variegatus ovaries the follicular population was estimated in 5,103.3 follicles, being 89% primordial, characterized by granulosa cells covering the oocyte containing a large nucleus; 7.0% of primary follicles, which had already had formation of the zona pellucida; 3.0% of secondary follicles, with several layers of granulosa cells, zona pellucida and developing inner teak. The tertiary follicles (1.0%) were characterized by the production of follicular fluid stored in the antrum, in addition to the presence of the teas. No preovulatory follicles were observed in the ovaries studied. Thus, the records of B. variegatus in the CETAS - Araguaína, as well as the field observation confirm the occurrence of the Legal Amazon species. In addition, it was concluded that common sloth has ovarian morphology similar to that described for other domestic and wild mammals, presenting for the first time an estimate of follicular population for this species in Araguaína.