Acute Toxicity of Aqueous Crude Leaf Extract of Azadirachta indica (NEEM) on The Gill Biochemistry of Clarias gariepinus (African catfish) Juveniles

Abstract

The indiscriminate discharge of pollutants into the water system by human activities is causing a momentous threat to the aquatic environment and leading to scarcity of fish and other aquatic fauna. This study was carried out to determine the acute toxicity test of the aqueous crude leaf of Azadirachta indica extract on the gill of Clarias gariepinus (African Catfish) juveniles by assessing the phytochemicals, investigation of changes in water quality parameters and biochemical parameters. A total of 120 mixed-sex juveniles of C. gariepinus with (mean weight of 11.4g and mean length 12.5cm) were used for the experiment. Acute toxicity test (96hrs static non reneweable bioassay) was carried out with ten (10) fish each in six (6) circular tanks, each duplicate replicated. After a range finding test was conducted, fish were exposed to various concentrations of 1.00, 1.20, 1.50, 2.00, 2.50 and 0.00g/L which served as the control tank. Fish exposed to the various concentrations showed abnormal behaviour and mortality increased as the toxicant concentrations increased throughout the exposure period. The result of the phytochemical screening of the toxicant showed the presence of saponins, tannins, steroids, cardiac glycosides and anthraquinones, flavonoids with the absence of alkaloids. The result of the water quality parameters monitored during the experiment varied significantly (P<0.05). Biochemical parameters varied significantly (P<0.05), the activities of the Aspartate aminotransferase, Alanine transaminase and Alkaline phosphatase increased with increase in toxicant concentrations. The study revealed that the substance is toxic to the exposed fish at various concentrations and the result showed that the 96hrsLC50 caused 50% mortality. The toxicant Azadirachta indica had adverse effects on the water quality, behavioural signs, and the biochemical parameters of the exposed fish compared to the control tank. Therefore, the use of A. Indica in water bodies can lead to contamination of the aquatic ecosystem by causing threat to fish well-being and survival.