Acute Toxicity of Piscicidal Plant Extracts (Adenia cissampeloides)on Tilapia (Sarotherodon galilaeus) Juveniles

The piscicidal quality of water extracts of Adenia cissampeloides leaves on Tilapia (Sarotherodon galilaeus) juveniles was investigated in a static renewal bioassay to determine the median lethal concentration (LC50) at 96hour of exposure. Five graded concentrations of 800, 600, 400, 200 and 100 mg/litre of aqueous solution of A. cissampeloides and a control 0 mg/lOL were applied to S. galilaeus fingerlings in plastic tanks. The 96h LC50 of aqueous extract of A. cissampeloides to S. galilaeus under laboratory condition was 317mg/1. Behavioural changes such as erratic swimming, loss of reflex, hyper ventilation, increased surfacing frequency and jerky movements were observed prior to death. Histopathological changes in the liver of S. galilaeus juveniles observed are severe widespread vacuolar degeneration and necrosis, hepatocytes, hyperplasia and presence of large numbers of megalocytes. In the gills, there were denudation of gill filaments, swelling of chondrocytes and rarefication of cartilage within gill filament. These damages became severe with increasing concentration of the plant extracts.