Histopathological Alterations in the Vital Organs of African Catfish, Clarias gariepinus (Burchell 1822) Exposed to Sub-lethal Concentrations of Methylparaben

Abstract

Methylparaben (MeP), a widely used preservative in personal care products and pharmaceuticals, has raised environmental concerns due to its potential toxicity to aquatic organisms. The aim of this study was to investigate the effects of exposure to sub-lethal concentrations of MeP on the histology of the gills, liver, kidney, and intestine of Clarias gariepinus. Adult C. gariepinus were exposed to 0.74 or 1.48 mg/L MeP for 28 days after which the gills, liver, kidney, and intestine were excised for histopathological study. The control fish were maintained in water not contaminated with MeP. There was no observable histopathological lesions in all the tissues in the control group. The fish exposed to 0.74 mg/L had mild fusion of the gill filament, focal haemorrhage of the liver parenchyma, moderate infiltration of inflammatory cells in the kidney interstitial spaces and lamina propria of the intestine. However, there was congestion and mild haemorrhage of the gill arch, severe glycogenic and lipid-filled hepatocytes, periglomerular infiltration of inflammatory cells, and severely infiltrated lamina propria of the intestine with lymphocytes at the highest concentration (1.48 mg/L). The histopathological alterations observed in the tissues of C. gariepinus exposed to sub-lethal concentrations of MeP provide valuable insights into the toxicological effects of this preservative to aquatic animals. Hence, the use of MeP in these important products must be regulated.