Morfologia reprodutiva e dosagem hormonal em fêmea de jurará (Kinosternon scorpioides) criada em cativeiro

Abstract

Kinosternon scorpioides is a mud turtle found in flooded fields in the Amazonian region, commonly known in Maranhão as “jurará”. The indiscriminate hunting for use in local cuisine or as a selling product on the roads of the state makes this wild species vulnerable to extinction. Thus, because of lack of information about the species reproduction, this study aimed to characterize the morphology of the reproductive organs and verify the hormone levels of female mud turtles in captivity in the rainy and in the dry season. Six adult females had their reproductive tract viewed from macroscopic and ultrastructural exams of light microscopy and scanning electron microscopy. Blood samples were obtained for hormonal dosage of estradiol, progesterone and corticosterone by radioimmunoassay. Results showed that all females were sexually mature and were in vitellogenic period. The species ovaries are two irregular structures consisting of several follicles in development (primary, secondary and tertiary) on a stroma of loose connective tissue richly vascularized with a mean weight of right and left respectively of 6.25g and 2.26g. Gonadosomatic index of 2.06% for the dry season and 1.79% for the rainy season. Mean number of follicles was 29.83 units per ovary. Histologically, the mature ovaries had a basal layer composed of four cell layers: external and internal teaks, granular layer with perivitelline membrane and the radiate zone with vitelline membrane. However, no significant differences were observed in the ovaries between the two studied periods. The oviducts are divided into five morphologically distinct regions, in which the epithelium has invaginations forming folds of varying heights and widths. Microscopically, the oviduct has an epithelium which varies from simple cuboidal to pseudostratified columnar, with ciliated and non ciliated mucusproducing cells. The infundibulum is a segment without glands, with high and thin folds, well-vascularized submucosa and delicate muscular layer. The magnum with a large submucosa, filled with serous tubular glands, lower and less folded epithelium, with thin muscular layer. The isthmus region is short, without glands, with high and branched folds. The uterus is easily recognized by the primary folds, very thick and high, with glands. The vagina has no glands and has a very thick muscular layer, with high and thin folds. Medium concentrations of progesterone, estradiol and corticosterone in the dry and in the rainy seasons were 0.18 and 0.33 ng/ml; 155.88 and 206.03 pg/ml; 3413.28 and 2918.52 ng/ml, respectively. We did not notice hormonal and morphological differences between the animals and the period of the year studied.