Histopathological profiles of hybrid catfish Heteroclarias exposed to
monocrotophos and rats fed a monocrotophos-contaminated diet
Olufemi. D. Owolabi, Saratu I. Abdulkareem
Department of Zoology, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria.
Corresponding author: Olufemi D. Owolabi
E-mail: olulabi@unilorin.edu.ng; Phone: +2348034313927,
ABSTRACT
Background: Monocrotophos (MCP) is commonly used in North Central Nigeria as avicide against birds in rice fields. Exposure of fish to MCP when released into aquatic environments could elicit changes in the histology and function of organs such as gill and liver. These changes could also manifest in the tissues of man upon consumption of fish from such polluted water.
Objectives: This study is aimed at elucidating the histopathological effects of MCP on the tissues of hybrid catfish, Heteroclarias and that of rat fed diets containing contaminated Heteroclarias. Methods: Two different experiments were conducted to test the toxicity of MCP on Heteroclarias and albino rat. In the first experiment, Heteroclarias were assessed in a static renewal bioassay for 28 days by exposure to six varying concentrations of MCP (0.00, 0.15, 0.20, 0.25, 0.30, and 0.35µg/l. In the second experiment, rats were fed with diet compounded with MCP-contaminated fish for 30 days. At the end of the experiments, the
gill and liver of fish and the liver and kidney of rats were removed for histological assay.
Results: Fish and rat tissues of the control showed normal structural architecture, while those of the treated animals exhibited apparent histological lesions such as hyperplasia, lamella fusion, vacuolation, fibrosis, hemorrhage and necrosis. The severity of each lesion in the tissues was concentration dependent.
Conclusion: The study shows that sub-lethal concentration of MCP is harmful to Heteroclarias and the consumption of MCP-contaminated Heteroclarias can lead to hepatic and renal dysfunctions; which could become a serious public health issue.
Keywords: Monocrotophos, Heteroclarias, monocrotophos-contaminated diet, Rat, Histopathology.