Effect on plasma cholinesterase levels and biomarkers of genotoxicity in hatchling quails from eggs treated with Chlorpyrifos during incubation

Abstract

Chlorpyrifos (CPF), an organophosphate insecticide, poses risks to wildlife and remains widely used in agriculture globally despite regional restrictions, posing significant risks to non-target wildlife. This study investigates the genotoxic and neurotoxic effects of CPF on Coturnix coturnix chicks following topical exposure of eggs during incubation. Eggs were treated with varying doses of CPF (38.4, 192.0, and 384.0 µg/egg) on days 1, 4, and 14 of incubation to simulate field spraying conditions. Genotoxicity was assessed by quantifying nuclear abnormalities in erythrocytes using the Micronucleus–Cytome assay, while neurotoxicity was evaluated by measuring plasma cholinesterase (ChE) activity. Results showed a significant increase in micronuclei and notched nuclei frequencies in CPF–treated groups compared to controls, indicating genotoxic effects. Furthermore, plasma ChE activity was reduced in CPF–exposed chicks, with the most significant reduction observed in the group exposed on day 4 of incubation. These findings suggest that topical CPF exposure during embryonic development can induce both genotoxic and neurotoxic effects in C. coturnix chicks, highlighting the potential risks of CPF to avian populations in agricultural environments. This study supports the use of embryonated quail eggs as a valuable model for assessing the toxicity of environmental contaminants on birds and underscores the sublethal threats that current-use pesticides pose to avian reproductive success.