Efeitos da exposição ao Roundup® no desenvolvimento embrionário de Podocnemis expansa (testudines: podocnemididae)

Abstract

Despite studies and scientific evidence demonstrating the harmful consequences and negative socio-environmental impacts of their use, the consumption of pesticides continues to grow in Brazil. Glyphosate is one of the most used pesticides in Brazil and in the world, and the commercial formula known as Roundup® is one of the main products sold. Considering the harmful damage caused by this herbicide, the present study aimed to evaluate the morphological effects of Roundup® on Podocnemis expansa during its embryonic development. To carry out the experiment, eggs were collected on the artificial spawning beach, located at the Center for Research and Rehabilitation of Wild Animals (CEPRAS) downstream from the Balbina HPP, and at the same time a natural nest at the Center for the Study of Chelonians in the Amazon (CEQUA - INPA ) was monitored for egg collections on certain days. The eggs removed from the nests were transported to the laboratory of comparative anatomy and morphology at UFAM and artificially incubated. The eggs exposed to Roundup® (1.3mg/l of glyphosate) were incubated in vermiculite moistened with a solution of distilled water and Roundup® and humidified with the same solution every 10 days (10, 20, 30, 40, 50 and 60 days of incubation). All treatments had their temperature controlled using a datalogger, the control treatment and Roundup® were humidified daily with distilled water to maintain ideal humidity, which was also monitored throughout the experiment. Throughout the entire embryonic development, embryos were collected (42º, 51º, 56º, 60º, 65º, 71º and 74º days of incubation), while in the natural nest of CEQUA embryos were collected (40º, 51º and 60º days incubation). Blood samples were collected for analysis of genotoxic damage through erythrocyte nuclear alterations. Liver and kidney samples were subjected to histological analysis. Embryos exposed to Roundup® showed genotoxic damage with increased numbers of micronuclei and erythrocyte nuclear changes (binucleate or multinucleate, reniform, and significantly lobed) the total number of ANEs was also significantly higher in the Roundup® treatment. A significant increase in defense cells was observed in Organs liver and kidneys and blood smears were analyzed, indicating a greater immune response caused by the toxicity of the Roundup® product. In livers, several histological changes were observed, including necroses that are irreversible and significantly higher AHIs in livers from treatment exposed to Roundup®. In the kidneys, vessel congestion, leukocyte infiltrations and, mainly, corpuscular congestion were observed and all these alterations showed significant differences between the treatments, with CEQUA and control being statistically similar and the treatment exposed to Roundup® greater than both, in addition, the congestions found would hinder the normal functioning of the organ. However, the results of the analyzes, both in blood and in liver and kidneys, showed that Roundup® affects the health and development of P. expansa embryos.