Abstract

Ayoola Simeon Oluwatoyin

The effect of aqueous and ethanolic extracts of Ipomoea aquatica leaf on the histopathology of selected organs of the fresh water Oreochromis niloticus was investigated. The differential acute toxicity of aqueous and ethanolic extracts of I. aquatica leaf on Nile Tilapia, O. niloticus were carried out under laboratory conditions. The LC50 after 96 h of exposure for aqueous and ethanolic extracts of Ipomoea aquatica were 2.659 and 0.196 g/L, respectively. These values showed that ethanolic extract of I. aquatica was more toxic than its aqueous extract. Signs of agitated behaviours, respiratory distress and abnormal nervous behaviours including eventual deaths were observed in exposed fish. Control fish neither died nor exhibited any unusual behaviour. Histopathological changes of gill, liver and muscle were noticed when O. niloticus was exposed to aqueous extract of I. aquatica for 96 h. In the gills, filament cell showed lesion, necrosis, malignancy, cellular degeneration and inflammation. In the liver, there was vacuolation of hepatocytes, inflammation and necrosis. In the muscle there was mild lesion, necrosis, inclusion bodies, inflammation and cellular degenerations. Similar result was obtained when the tested organism (O. niloticus) was exposed to ethanolic extract of I. aquatica for the same duration and under the same laboratory conditions. But the level of tissue and organ degeneration is more severe in the case of the ethanolic extract than in aqueous extract. This investigation revealed that leaf of I. aquatica has piscicidal property and can be put into use in the control and management of fish ponds by farmers. Therefore, this plant can actually be use as a biological control in eradicating predators and unwanted organisms in the ponds by farmer instead of using agrochemicals.