TOXIC EFFECT OF THE INSECTICIDE FIPRONIL ON NILE TILAPIA (Oreochromis niloticus)

Abstract

Fipronil is a phenylpyrazole insecticide widely used in agriculture and veterinary medicine. Due to its excessive use, fipronil has raised significant concerns because of its toxic effects on the environment. The present study aims to evaluate the impact of fipronil on the activity of the enzymes acetylcholinesterase (AChE), catalase (CAT), and glutathione S-transferase (GST) in Nile tilapia (Oreochromis niloticus). Fish were exposed to different concentrations of fipronil (0.0 - 0.064 mg/L) for 96 hours, and enzyme activity was analyzed in brain, gill, and liver tissues. The results showed a significant inhibition of AChE in the brain, indicating interference with neurotransmission. CAT was inhibited in the brain and gill tissues, while the liver showed enzyme activation at low concentrations and inhibition at higher concentrations. GST activity increased in the brain, but no significant enzymatic changes were recorded between the control and treatment groups in the gill and liver tissues. It is concluded that fipronil may induce oxidative stress and impair physiological functions in tilapia, posing a potential risk to aquatic organisms.