Comparative Toxicological Effects of the Herbicide, Atrazine, on Fingerlings and Juveniles of African Catfish, Clarias gariepinus (Burchell, 1822)

This research was aimed at evaluating the toxic effects of atrazine, a commonly used herbicide on acetylcholinesterase (ACHE) activity, lipid peroxidation and testosterone levels in different growth stages of African catfish, Clarias gariepinus (Burchell, 1822). The acute and the chronic evaluations were conducted while activities of acetylcholinesterase, lipid peroxidation and testosterone levels were determined using predetermined sub - lethal concentrations of the herbicide. The mean 96-h lethal concentration (LC50) of atrazine exposed to catfish fingerlings and juveniles were 0.350 mg·L-1 and 0.553 mg·L-1, respectively. Acetylcholinesterase activity was higher in the brain of juveniles (25.0 μmol·mL-1) exposed to the herbicide than that of the fingerlings (17.0 μmol·mL-1), and a similar pattern was observed in the liver. Malondialdehyde was higher in the fingerlings (liver and brain) (2.7 and 2.0 μmol·mL-1) exposed to the herbicide than the juveniles (1.8 μmol·mL-1 and 1.6 μmol·mL-1). Testosterone was not detected in the serum of fingerlings exposed to atrazine herbicide. The results of this study elucidated potential biomarkers for monitoring fish health in rivers receiving runoffs of the herbicide, atrazine, and the risk of loss of fisheries productivity attributable to the anti-androgenic properties of the herbicide.