EFEITOS DO GLIFOSATO EM CONCENTRAÇÕES PERMITIDAS POR LEI EM RESPOSTAS OXIDATIVAS E HISTOPATOLÓGICAS DE FILHOTES DE TARTARUGA-DA-AMAZÔNIA (Podocnemis expansa)

Abstract

Glyphosate, the most sold herbicide both internationally and nationally, is used for weed control in agriculture, particularly in the Amazon. Some studies have shown harmful effects of glyphosate on Podocnemis expansa (Amazonian turtle) embryos, highlighting the need to understand the potential effects on P. expansa hatchlings exposed to glyphosate concentrations permitted by Brazilian legislation. The aims of this study were to understand possible histopathological alterations and oxidative damage associated with exposure to glyphosate at concentrations allowed by Brazilian legislation and to assess the recovery capacity of Podocnemis expansa hatchlings. This experimental study consisted of five treatments (n=5): control group (no exposure to any contaminants); group exposed to a low concentration of glyphosate corresponding to 50% of the limit established by the National Environment Council for water presence; group exposed to 65 μg/L of glyphosate as per the limit set by the National Environment Council (Resolution CONAMA No. 357, March 17, 2005); recovery control group; recovery group after exposure to the lower concentration; recovery group after exposure to the concentration established by legislation. The levels of lipid hydroperoxides and carbonylated proteins were similar between the groups exposed to glyphosate and the control group in both liver and muscle. In the testes of the analyzed specimens, circulatory disturbances were observed, such as leukocytic infiltration and small hemorrhagic foci, as well as structural changes like disorganization of the seminiferous tubules in the medullary region. However, the testicular ILO was similar between the different treatments, showing low values that indicate normal tissue structure. In the intestine, changes such as leukocytic infiltration, vacuolization, villous shedding, hypertrophy of the muscle layer, and necrosis were observed. The organ lesion index (ILO) was significantly higher in the groups exposed to the two concentrations of glyphosate compared to the control group. The observed values indicate mild and moderate alterations. After the recovery period, a significant reduction in ILO was observed only in the group previously exposed to 65 μg/L. The results of this study show that the 65 μg/L glyphosate concentration in water, permitted by Brazilian legislation, is harmful to Podocnemis expansa hatchlings, and these animals demonstrated partial recovery capacity during the 14-day evaluation period.