Dose-Response Relationship and Histo-morphological Alterations on Oreochromis niloticus Juveniles Following Exposure to Ethanolic Extract of Latana camara

Abstract

Aim: This research intends to evaluate the toxicity of latana camara and ascertain if it can be useful as a plant-based additive in the formulation of fish feed. Study Design: The study was conducted using two replicate (Batch A and B) for 96 hours under controlled laboratory conditions. Five concentrations ranging from 0, 5, 10, 15, and 20 mg/l were prepared from the ethanolic extract (EE) of L. camara for the toxicity test. Place and Duration of Study: Experiment was conducted in Akwa Ibom State University, Obio Akpa Campus, Akwa Ibom State between February, 2023 and June, 2023. Methodology: Total of two hundred (200) juveniles were collected for the studies. One hundred (100) juveniles were used during range findings test and the left over for the actual toxicity test. Prior to commencement of the toxicity test, experimental fish were allowed to acclimatize. Each of the ten (10) plastic aquaria was stocked with ten (10) O. niloticus juveniles. The prepared plant extract at varying concentration was added to each stock aquaria and allowed to stand for 96 hours for mortality examination. Gills tissues were isolated from the fish samples in each of the concentration after 96 hours for histopathological examinations. Results: The experimental animals showed differential percentage mortalities with toxicant concentrations. The 96 hours LC50 for O. niloticus for both batches (A and B) was given at 7.346 mg/l representing a log transformed concentration of 0.866 mg/l. The different batches of O. niloticus (P = .05) had no significant difference in mortality. The results of the present study suggest that the EE of L. camara had severe impacts on the test organism resulting in mortality. The effects of L. camara on the gills of O. niloticus Juveniles showed severe impacts on the test organisms. Five samples were taken from each of the concentrations to examine the effects of the extract on the gills of O. niloticus. There were no observed changes in the gills of the control group as compared to other treatment which showed evidence of histological alterations. Conclusion: From the findings, it is observed that extract obtained from L.  camara is toxic to aquatic life and cannot be recommended as a plant-based additive in the formulation of fish feed.