Descrição do perfil hormonal de matrizes e reprodutores de tartaruga-da-Amazônia (Podocnemis expansa, Schweigger, 1812) em cativeiro no Amazonas

Abstract

Information on the reproductive biology of Podocnemis expansa is crucial for captive management purposes. This study aimed to describe the reproductive, biometric, environmental characteristics and relate the levels of circulating gonadal steroid hormones and plasma biochemical profile with the reproductive stages of P. expansa in captivity in Amazonas. A total of 167 blood samples were collected, in the four (4) seasons of the reproductive states: March (vitellogenesis), May (mating), August (sunbath) and October-November (spawning) of males and females in a commercial breeder in Iranduba. We also record biometric information on adults, nests and chicks. In addition to monitoring the embryonic period, hatching and offspring sexing. In each collection, environmental data on pH, BOD and water and beach temperature were collected. In the hormonal analysis, dosages for testosterone and estradiol were performed, using the ELISA technique and biochemical analyzes (total proteins, calcium, cholesterol, triglycerides, glucose, sodium and potassium). Thus, for environmental conditions, it was observed that the pH and BOD contents vary throughout the reproductive cycle for P. expansa bred in captivity. There was no variation in the size and weight of females and males throughout the reproductive cycle, on the other hand, there was a difference in the size and weight of eggs. The size of the animal had an influence on the number of eggs and incubation time of the offspring. For hormonal results, estradiol varied equally in females and males, with peaks in vitellogenesis. There were no significant differences between testosterone levels in either sex. Among the biochemical parameters, the levels of cholesterol and triglycerides varied, in females, they had their highest averages between the vitellogenic and mating phases. In males there were variations only for triglycerides, with an increase in spawning. For glucose there was also variance, in females the levels were lower in sunbath fase and in males there was an increase in the vitellogenic state. As well as there was productive, in the levels of total protein in females and males. That similarly showed higher levels in the spawning phase in both sexes. Significant differences in calcium levels were observed only in males. Changes in sodium levels were found in females and males, with peaks in vitellogenesis. Circulating lipid levels are significantly positively associated with the E2:T ratio in females. The results obtained in this study may support other studies aimed at inducing spawning and better management in captivity.