Ecotoxicological Effects of Glyphosate-based herbicide Sub lethal Concentration on DNA Damage, Antioxidant Response and Histo-physiological consequences in Common carp (Cyprinus carpio)

Glyphosate-based herbicides (GBHs), a class of organophosphate pesticides, are extensively applied worldwide and their residues pose significant ecological risks, particularly in aquatic ecosystems. This study evaluated the effects of sub-lethal GBH concentrations on DNA integrity, peripheral erythrocytes, and antioxidant enzyme responses such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in Cyprinus carpio (common carp). Forty fish were distributed into four groups: control (untreated) and three experimental groups (E1, E2, E3) exposed to 0.4, 0.8, and 1.5 ppm GBH, respectively, for 7, 14, 21, and 28 days. At the lowest concentration (0.4 ppm), GBH caused a mild reduction in antioxidant enzyme activities, maintaining reactive oxygen species (ROS) at a manageable level. However, higher concentrations (0.8 ppm and 1.5 ppm) led to excessive ROS generation, overwhelming the antioxidant defense system and depleting enzymatic activity. DNA damage, assessed through single-cell gel electrophoresis (comet assay), increased in a dose-dependent manner. Similarly, micronucleus frequency in peripheral erythrocytes rose with elevated GBH exposure. Histopathological examination of gills revealed lesions such as hyperemia, epithelial hypertrophy and atrophy, lamellar shortening, and pillar cell distortion. In conclusion, sub-lethal exposure to GBH (0.4ppm, 0.8 ppm &1.5 ppm) induces oxidative stress, genotoxicity, and histopathological alterations in C. carpio , highlighting its potential toxicity to aquatic organisms.