Herbicide Mixtures from Usual Practice in Sugarcane Crop: Evaluation of Oxidative Stress and Histopathological Effects in the Tropical Fish Oreochromis niloticus

Jonsson, ClaudioMartin; Arana, Sarah; Ferracini, VeraLucia; Queiroz, SoniaClaudia Nascimento; Clemente, Zaira; Vallim, JoséHenrique; de Holanda Nunes Maia, Aline; de Moura, MônicaAccaui Marcondes

Herbicide Mixtures from Usual Practice in Sugarcane Crop: Evaluation of Oxidative Stress and Histopathological Effects in the Tropical Fish Oreochromis niloticus

2017

Sugarcane is one of the world’s most important commodities. In order to control weeds in the plantations and increase productivity, the mixing of different herbicides during spraying operations is commonplace. This practice is unregulated, and the impact on water quality and nontarget tropical species is poorly understood. In the present work, exposure and recovery assays were used to evaluate antioxidant enzyme activity and histopathological alterations in the liver of tilapia (Oreochromis niloticus) following exposure to mixtures of the herbicides widely used in sugarcane crops: ametryn (AMT), tebuthiuron (TBUT), diuron (DIU), and hexazinone (HZN). The greatest biochemical changes were observed for the mixture (DIU+HZN)+AMT+TBUT at the highest concentration tested (1/10 96hLC50). This mixture caused a significant increase (p < 0.01) of approximately 82% in GST activity after 14 days of exposure. For three of the mixtures evaluated, GST and CAT could be considered potential biochemical biomarkers of exposure to the herbicide mixtures due to the frequency, intensity, and statistical significance of alterations in the assimilation phase. Although morphological changes were evident in the hepatic tissue, severe damage was only noted in a few samples, and there were no statistically significant differences, relative to the control. The results of hepatic lesion recovery assays suggested that the most sensitive individuals affected by the xenobiotics were unable to achieve full recovery. It is anticipated that the data obtained may assist in the selection of biomarkers for monitoring purposes, as well as in reinforcing standards of conduct in the use of agrochemical mixtures in agriculture.

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