STUDIES ON ACUTE TOXICITY OF PISCICIDAL PLANT EXTRACTS (TETRAPLEURA TETRAPTERA) ON TILAPIA ( SAROTHERODON GALILAEUS) FINGERLINGS

Abstract

Ethanolic extracts of dried, ripe fruits of Tetrapleura tetraptera was used to test the toxicity tolerance in Tilapia sarotherodon galilaeus fingerlings. Five graded concentration of 4.5, 10.0, 22.0, 45.0, 1M) mg liter of water (weigh/Volume) and a control Omg/151 of water (represented by Aquaria A, B, C, D, E and F (where “A" served as a control). Ethanolio extracts of dried, ripe fruits of T. tetraptera were tested toxicity under laboratory conditions with a 96h kc 50 of 675mg1151 (weight/ Volume). The mean mortality percentages were 13.13, 26.66, 30.00, .W.00, and 100.00 % in the order of concentration of 4.5,10.0,22.0,45.0,1081ng/litre (weight/volume),
respectively, while there was no mortality in the control treatment. There were significant differences (P<0.05) on the effect of, concentration of tetraptera on total mortality percentage. The higher the concentration, the higher the mortality of the S.gnlilnerrs fingerlings while toxicity of 7'. tetraptera reduced with time. Histopathological examination of fish without ethanolic fruits extract showed that there was no lesion: hut histopathological changes were observed in other fish subjected to differegt concentrations of ethanolic fruits extract of 7'. tetraptera. S. gniilne~rs fingerlings succumbed only to higher concentrations of tetraptera ethnolic fruits extract within 9-54 hours. Thus, it is possible to use the extract in selective eradication of aquatic organisms in nursery and rearing ponds before stocking.