HISTOLOGICAL STUDY OF AFRICAN CATFISH CLARIAS GARIEPINUS GILL EXPOSED TO METHYLPARABEN

This study investigated the histopathological effects of methylparaben on the gill of Clarias gariepinus, an economically important freshwater fish species. Parabens, particularly methylparaben (MeP), are widely used preservatives in pharmaceuticals and personal care products and are increasingly detected in aquatic environments where they may pose toxicological risks to aquatic organisms. The gill, being the primary site of respiration, osmoregulation, and excretion, serves as a sensitive biomarker for assessing contaminant-induced stress. A total of nine (9) C. gariepinus broodstock were exposed under laboratory conditions to graded concentrations of MeP (0, 0.74, and 1.48 mg/L) for 28 days. Gill sections from each treatment group were processed and examined using standard histopathological techniques. Photomicrographs of the control gills showed intact primary filaments and secondary lamellae with minimal baseline cellular activity. At 0.74 mg/L MeP, epithelial sloughing was observed along the secondary lamellae, suggesting oxidative stress-mediated epithelial damage. At 1.48 mg/L, moderate infiltration of inflammatory cells was evident in the interlamellar and subepithelial regions, indicating activation of mucosal immunity and impairment of respiratory efficiency. The observed lesions were concentration-dependent, with increasing severity across exposure levels. This study shows that MeP exerts deleterious effects on the gill of C. gariepinus, even at sublethal concentration. It is, therefore, recommended that stricter monitoring and regulatory measures be implemented to limit methylparaben contamination, and further studies should integrate biochemical and molecular endpoints to elucidate mechanisms underlying branchial injury in exposed fish.