Effects of Gabapentin, Valsartan, and Codeine on hemato-biochemical and histological biomarkers of male catfish (Clarias gariepinus)

Pharmaceutical residues in aquatic environments are emerging contaminants of concern due to their potential sublethal and chronic impacts on aquatic organisms. This study aimed to evaluate the subacute toxicological effects of three widely used pharmaceuticals-gabapentin (GAB), valsartan (VAL), and codeine (COD)-on male African catfish (Clarias gariepinus). Fish were randomly assigned to four groups: a control group and three treatment groups exposed for 15 days to environmentally relevant concentrations of GAB (79.86 µg/L), VAL (28.22 µg/L), and COD (5.27 µg/L), respectively. Hematological indices including hematocrit (Ht), hemoglobin (Hb), erythrocyte (RBC), leukocyte (WBC), and lymphocyte counts were significantly reduced in all exposed groups relative to controls. Biochemical analysis revealed elevated levels of AST, ALT, glucose, total protein, total cholesterol, uric acid, and creatinine in the GAB group, while VAL exposure led to increased total protein and creatinine levels and decreased alkaline phosphatase (ALP) activity. Antioxidant assessments showed a significant reduction in superoxide dismutase (SOD) following VAL exposure, with total antioxidant capacity (TAC) and catalase (CAT) activities significantly reduced across all treated groups. Histopathological and histochemical examinations of the liver revealed tissue degeneration, fibrosis, and glycogen depletion, with the most severe alterations observed in the VAL group. These findings highlight the potential adverse effects of chronic pharmaceutical exposure on fish physiology and liver function, with VAL demonstrating the most pronounced impact among the tested compounds.