Oxidative and Antioxidant Responses in Daphnia magna Following Exposure to Sub-Lethal Glyphosate Concentrations

Abstract: Glyphosate (GLY) is one of the most widely used herbicides in modern intensive agriculture to enhance crop production. However, the chemical additives in commercial formulations and the active ingredient itself can adversely affect biological and chemical processes in aquatic organisms. Therefore, the aim of this study was to evaluate the effects of sub-lethal concentrations of GLY (0, 0.23, 0.58, and 1.17 μg/L) on oxidative stress biomarkers—namely lipid peroxidation (measured as malondialdehyde, MDA), and antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and reduced glutathione, GSH)—in Daphnia magna after 24 and 96 h of exposure. The results showed that SOD activity increased in all treatment groups compared to the control at both time points while CAT activity decreased in all groups. GSH and TBARS (thiobarbituric acid reactive substances) levels were significantly elevated after 24 and 96 h in all exposed groups. Overall, D. magna was sensitive to sub-lethal concentrations of GLY, and changes in SOD and CAT activities, as well as GSH and TBARS levels, these biomarkers can serve as useful indicators for detecting glyphosate-induced oxidative stress and water pollution.