Toxic effect of organophosphate (chlorpyrifos) on hematological, biochemical, enzymatic and histological parameters in striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878)

This study evaluated the impact of chlorpyrifos (CPF) on haematological parameters, enzymatic activity, biochemical indices, and tissue histology of striped catfish (Pangasianodon hypophthalmus). Fish were exposed to two sublethal concentrations of chlorpyrifos-20 EC (T1: 0.0106 mg L−1 and T2: 0.0212 mg L−1), along with a control group (0.0 mg L−1), for 45 days. The 96-h LC₅₀ value of chlorpyrifos-20 EC was determined as 0.106 mg L−1. Blood and tissue samples were collected on days 15, 30, and 45 for analysis. CPF exposure caused a significant decline in RBCs count, haemoglobin, haematocrit, total protein, albumin, and globulin, while WBCs count, mean corpuscular volume, mean corpuscular haemoglobin, serum glucose, and triglycerides were elevated. Serum enzymatic activities acid phosphatase (ACP), alkaline phosphatase (ALP) and aspartate aminotransferase (AST), alanine aminotransferase (ALT) and acetylcholinesterase (AChE) showed significant (p < 0.05) alterations, and antioxidant enzymes (SOD and catalase) were markedly reduced in treated groups. Histopathological alterations in the gill, liver, and kidney were more pronounced in T2 than in T1. Overall, CPF exposure induced severe haematological, biochemical, enzymatic, oxidative stress, and histological disturbances in striped catfish, indicating its potential risk to fish health and aquatic ecosystems.