Efeitos toxicológicos do Dimilin® em machos adultos de Hyphessobrycon eques (Steindachner, 1882) (Teleostei: Characidae)

• Autor(a) principal: Goulart, Amara Manarino Andrade
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5126
• topic: Hyphessobrycon eques; Diflubenzuron; Bioindicador; Hyphessobrycon eques; Diflubenzuron; Bioindicator; CNPQ::CIENCIAS AGRARIAS::RECURSOS PESQUEIROS E ENGENHARIA DE PESCA::RECURSOS PESQUEIROS DE AGUAS INTERIORES::MANEJO E CONSERVACAO DE RECURSOS PESQUEIROS DE AGUAS INTERIORES

The mishandling of pesticides leads to aquatic environment contamination causing lesions in fish. Biochemical, physiological and morphological are biomarkers that show good results in the evaluation of the lesions of environmental contamination on these animals. The Dimilin ®, purpose of this study, is used to control ectoparasites of fish and due to lack of data from their injuries in neotropical fish, the objective is to determine the effects of LC50 of Dimilin ® on sexually mature males from mato grosso (Hyphessobrycon eques) as well as their effect on testicular morphology in toxicity testing in exposure times of 96 hours and 17 days in static system. The calculation of CL50 was conducted in the program TOXCALC (USEPA, version 1.5) with the calculation to determine the binomial confidence by reducing the interval moving average (P<0.05). The toxicity tests followed the ABNT technical tests in static system. For toxicity tests, it was used a control group and three groups with concentrations of 0,01, 0,1 and 1 mg L-1 of Dimilin ®. For the 96 hours test, it was used a single application at the beginning of the experiment. For the 17 days test, it was used two applications (in the beginning of the experiment and 72 hours after the first application). Water samples were collected for the aquarium physicochemical analyzes. After the experimental periods, the testicles of 10 animals from each group were collected and processed for routine histological study. We observed 10 samples per animal considering morphometric and histopathological aspects. The CL50 calculated in this test was 22.4 mg.L-1, and the confidence interval obtained by the moving average was 13.9 to 34.8 mg l-1 (P<0.05) at a mean temperature of 22.4 º C. Analysis of the water showed that the parameters were within the desirable values for fish farming. Among all testicles parameters observed, there was a reduction of B spermatogonia counting in both experiments, with no differences between experiments. In the 17 days experiment, differences were observed for altered tissue and healthy tissue of the control group compared with the other concentrations (p <0.05), with no differences for the 96 hours experiment or 96 hours and from 17 days. Nuclear pyknosis were observed, tissue disorganization characterized by the presence of spermatids in the testicular parenchyma and presence of spermatocytes in the lumen of the tubule, the presence of red blood cells out of the blood capillaries, the presence of vacuoles in the cytoplasm of spermatogonia and spermatocytes and fibrosis. Thus H. eques can be used as bioindicator and his testicles as biomarkers of aquatic pollution by Dimilin ®.