Avaliação do potencial mutagênico de diferentes concentrações de thiametoxam e ensaio de dl50 em Astyanax altiparanae

Abstract

The objective of this study was to evaluate the mutagenic potential and estimate the LD50 value of thiamethoxam in Astyanax altiparanae. The animals were collected in a fish farm belonging to the region of Dourados and later were taken to the laboratory and allowed to acclimate to the stage of phase exposure to thiamethoxam in different concentrations ( Group 1 = 60 mg L- 1 and Group 2 = 125mg L- 1 ) . For analysis of mutagenicity , the thiamethoxam was applied in aquaria at different concentrations previously defined . After 96 hours of exposure to the preparation of slides for subsequent counting micronucleus was performed . For the LD50 test , at the end of 96 hours of exposure, the estimate was made of the surviving fish. For analysis of mutagenicity the Kruskal -Wallis test followed by Nemenyi - Damico - Wolfe -Dunn test, whereas the LD50 for the test was made logistic regression was performed . The Kruskal -Wallis test showed no significant difference in Group 1 compared with the control group, while Group 2 showed a significant difference, with p values < 0.001, also when compared to the control group. The logistics for the estimated LD50 regression was 113.3 mg L- 1, lower than that found for rainbow trout and some other organisms used for toxicological tests, possibly due to sensitivity of A. altiparanae value. The current work might check for genetic modification in animals subjected to thiamethoxam, but more tests are needed to determine the impact of this pesticide residues in nature, such as the comet assay and histopathological tests.