Establishing a Dose-response Toxicity for Clarias gariepinus Fingerlings Exposed to Ethanolic Extract of Lantana camara

Abstract

The toxicity of lantana camara on the survival and histopathology of gills of Clarias gariepinus fish from Fisheries unit, Akwa Ibom State University Obio Akpa, farm was studied in two batches (A, and B) using the ethanolic extract (EE) of Lantana camara for 96 hours under laboratory conditions. Five concentrations ranging from 0, 2, 3, 4, and 5 mg/L were prepared from the (EE) of L. camara for the toxicity test. The experimental animals showed different percentage mortalities with toxicant concentrations. The 96 hours LC50 for C. gariepinus for both batches (A, and B) was given at 2.983 mg/l representing a log transformed concentration of 0.475 mg/l a point where 50 % of the test organisms would be killed at the end of the experiment. The different batches of C. gariepinus (P>0.05) had no significant difference in mortality indicating that the ethanolic extract had same toxic effects on the test organisms. Toxicant exposure induced behavioral changes such as abnormal and uncoordinated swimming movement, restlessness, respiratory difficulties and attempt at jumping out was observed during the study. The results of the present study suggest that the ethanolic extract of L. camara had severe impacts on the test organism resulting in mortality. The effects of the plant extract on the gills of C. gariepinus fingerlings had severe impacts on the test organisms. Samples were taken from each of the concentrations to examine the effects of the extract on the gills of C. gariepinus. There was no observable change in the gills of the test organism in the control group. In the 2 mg/l concentration, the gill showed diffused epithelial degeneration of the primary lamella., in the 3 mg/l and 4mg/l concentration it was observed that the gills showed complete diffused epithelial degeneration of the lamella. Although cartilaginous filament of the epithelium was preserved between the two adjacent filament in skeletal muscle. Finally, in the 5 mg/l concentration the gill section showed diffused epithelial degeneration of the primary lamella and few retained processes of the secondary lamella. From the findings, it is observed that extract obtained from L. camara is toxic to aquatic life. Therefore, effective management strategies should be put in place to ensure safety compliance.