Toxicological Evaluation and Histopathological Changes of Synthetic Pyrethroid Pesticide (Cypermethrin) Exposed to African Clariid Mud Catfish (Clarias gariepinus) Fingerlings

Abstract

The study of the toxicological and histopathological changes of Clarias gariepinus fingerlings exposed to different concentrations of cypermethrin is of great importance due to the fact that it helps reveal the extent of toxicological damages of cypermethrin on fishes. Cypermethrin is globally used for control of pest, but it is washed along with run offs into the aquatic ecosystem, and this has an effect on the non-target species, thereby killing various fauna within the aquatic eco-system. Ten (10) fingerlings of Clarias gariepinus were introduced into each aquarium containing twenty (20) litres of water with 25ppm, 50ppm, 75ppm, 100ppm, 125ppm and 0.0ppm (Control) concentrations of cypermethrin and its effects were observed for 96hrs. The Clarias gariepinus fingerlings exposed to different concentrations of cypermethrin exhibited signs of stress and erratic movement. All the time-effect relationship was found to be concentration dependent. The fingerlings of Clarias gariepinus showed normal gill lamella, erosion of secondary gill lamella and haemorrhage of secondary gill lamella in the gill tissues when exposed to different concentrations of cypermethrin. The fingerlings exposed to the cypermethrin showed normal distribution hepatocytes, hyperplastic hepatic cells necrosis of hepatic cells in the liver tissues. A log concentration probit regression analysis was significant (p<0.05) yielding a co-efficient of determination, r2 of 0.973 and having a 96 hours LC50 with 95% confidence value of 1.80±0.28ppm. The study revealed that cypermethrin has toxicological and histopathological effects on different organs of Clarias gariepinus fingerlings.