Journal of Veterinary and Applied Sciences

Abstract
Aquatic pollution poses imminent risks to the wholeness of the ecology and food security, especially in environments where treatment of wastewater is inefficient or non-existent. The present study experimentally exposed African catfish (Clarias gariepinus) to sub-lethal levels of Bisphenol A (BPA) and evalauted its effects on the histology and levels of oxidative stress markers in the gills and muscles. One hundred and eighty fishes were used for the study. They were randomly assigned to six groups (Groups 1 – 6) of 30 each. Group 1 fishes were the Untreated Normal Control, while Group 2 fishes were exposed to the solvent (ethanol) used to dilute the BPA (Solvent treated control). Groups 3, 4, 5 and 6 were exposed to BPA at the levels of 2, 4, 6 and 8 mg/L, respectively. The BPA exposure lasted for 28 days. After day 28, the fishes were sacrificed and the gills and muscles were collected and used for assessment of levels of oxidative stress markers and also for histopathology, following standard procedures. Results showed that there was significant tissue (gills and muscles) toxicity which was dose-dependent. The concentrations of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), and the activity levels of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST) in the gills and muscles of the treated groups were significantly (p < 0.05) higher than those of the control groups, while the levels of reduced glutathione (GSH) was significantly (p < 0.05) higher in the controls when compared to the treated groups. There was also a significantly (p < 0.05) lower concentration of proteins in the gills and muscles of the treated groups when compared to the controls. In the BPA treated groups, there was proliferation and thickening of epithelial cells covering the lamellae of the gills with pillar congestion, the severity of which was dose dependent. Atrophy of the myofibres and accentuation of the interstitial spaces of the muscles were recorded for the groups treated with higher levels of BPA. It was concluded that exposure of juvenile catfish (Clarias gariepinus) to BPA at the levels used in the study led to signifcant alterations in markers of oxidative stress and histopathology of the gills and muscles of the treated fishes.

Keywords: Bisphenol A (BPA); African catfish (Clarias gariepinus); Gills; Muscles; Oxidative stress markers; Histopathology; Toxicity.

How to cite this article:
Asenuga ER and Edene OA (2026). Exposure of juvenile Clarias gariepinus to sub-lethal levels of bisphenol A: Effects on oxidative stress marker levels and histology of the gills and muscles. Journal of Veterinary and Applied Sciences, 16(1): 1340 – 1352.

*Correspondence: E-mail: ebunoluwa.olowu@uniben.edu.ng Phone: +2348052720219