African Journal of Fisheries Science

African Journal of Fisheries Science ISSN 2375-0715 Vol. 9 (4), pp. 001-008, April, 2021. © International Scholars Journals

Full Length Research Paper 

Toxicity bioassay and effects of sub-lethal exposure of malathion on biochemical composition and haematological parameters of Clarias gariepinus

Zubair Ahmad

Department of Zoology, College of Science, P. O. Box 2455, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia. Email: or

Accepted 13 March, 2020


Clarias gariepinus were exposed to different concentrations of malathion to determine the 96 h LC50 value and its sub-lethal effects on haematological parameters and biochemical composition were also investigated. The 96 h LC50 value concluded was 8.22 mg/L. Specimens of C. gariepinus were exposed to sub-lethal concentrations (0.5, 1.0 and 2.0 mg/L) of pesticide for 4 weeks, which revealed that the pesticide had an adverse effects on various blood parameters. Red blood cell (RBC) and white blood cell (WBC) counts, hemoglobin (Hb) concentration and haematocrit (Ht) values decreased after the exposure of malathion. Plasma glucose level was elevated as plasma protein decreased. Liver and muscle glycogen also decreased in the fish exposed to Malathion. Alanine amino transferase (ALT), glutamate oxaloacetate transaminase (GOT) and glutamate pyruvic transaminase (GPT) activities increased in the fish exposed to malathion. Magnesium and calcium ions were also affected, but the effects were insignificant.

Key words: Malathion, bioassay, sub-lethal exposure, Clarias gariepinus, biochemical and haematological changes.