Evaluation of the effects of impacted environment on fish vitellogenesis

Abstract

Vitellogenesis is an important phase of fish reproductive cycle and many ecotoxicological studies have been shown that some pollutants can negatively affect the physiological control of this process. Thus, the study of gene expression and plasma levels of vitellogenin (Vtg), the main glycolipophosphoprotein involved in vitellogenesis is important to determine how some pollutants may impair this phase of the reproductive process. In females, Vtg is produced in liver under the stimulus of 17 ²-estradiol, an estrogen produced in the ovarian follicular cells. However, the presence of xenobiotics in impounded environments can change its synthesis, threatening the reproduction and the conservation of fish population. Thus, the goal of this study is to evaluate the hepatic gene expression and plasma levels of Vtg in Astyanax fasciatus living in impounded environment. Our recent data have been shown that 17 ²-estradiol plasma levels were altered in A. fasciatus females living in impounded reservoir in São Paulo State, but there is a gap in the study of the Vtg in netropical fish species. The development of this project abroad is imperative considering that there is no Vtg antibodies developed for any species of the Characiformes order, one of the most widespread order of native fish. Moreover, beyond the development of these antibodies to be used specifically in our study, we will make available antibodies for future researchers studying Characiformes reproductive physiology and/or ecotoxicology. The measurement of hepatic Vtg expression and this lipoprotein in plasma, are important steps to understand the reproductive physiology of target fish species, mainly because this molecule is the precursor of the yolk protein. It is worth highlighting that the results of this proposal will be important to evaluate the anthropogenic (mainly estrogenic and antiestrogenic) impact in the reproduction of tropical fish. The knowledge of these news techniques also improve the understanding about how tropical fish adjust their physiologic process in impact environmental. This research area is essential for the development of important physiological tools to be applied in ecotoxicological studies in tropical fish species fish. Finally, CSIRO (The Commonwealth Scientific and Industrial Research Organisation) is considered a reference research center in the area of ecotoxicoloy and aquaculture, so it is a real honor and a privilege having a positive feedback from Dr. Anu Kumar to be accepted for this period in her laboratory. (AU)