Oxidative stress caused by a commercial presentation of glyphosate in two indigenous fish species of importance in Colombia

Abstract

The use of glyphosate to eradicate poppy (Papaver somniferum) and coca (Erythroxylon coca) plants is of great concern in Colombia due to potential effects on the environment. Juveniles of white cachama (n=36) (Piaractus brachypomus) (22.7 ± 2.9 g) and yamú (Brycon amazonicus) (n=36) (11.7 ± 1.1 g) were exposed for 96 h to three glyphosate concentrations (0, 5 and 15 ppm, v/v, as Roundup®). Enzymes linked to oxidative stress in liver and gills were measured after the exposure. The main oxidative stress changes happened in the gills of glyphosate-exposed cachama and liver of both species. There was a significant decrease in reduced glutathione (GSH) and glutathione-s-transferase (GST) activity of both species. Catalase activity was significantly reduced in livers of exposed cachama. Lipid peroxidation had a significant increase in glyphosate-exposed cachama (liver and gills) and yamú (liver). The biochemical changes found in both species and both organs indicate the oxidative effects of glyphosate as Roundup® despite the asymptomatic and non-lethal exposures.