Sublethal toxicity of carbofuran pesticide on the African catfish Clarias gariepinus (Burchell, 1822): hematological, biochemical and cytogenetic response.

The present work aimed to evaluate the toxic effects of two sublethal concentrations of carbofuran pesticide (0.16 and 0.49mg/L, for 35 days) on hematological and blood biochemical parameters of catfish, Clarias gariepinus, and to evaluate the genotoxic potential of carbofuran on the erythrocytes of C. gariepinus for the first time by micronucleus and erythrocyte alteration assays. The results revealed a significant (p<0.05) decrease in red blood cells (RBCs) count, haemoglobin (Hb) concentration, haematocrit (Hct) and the mean corpuscular haemoglobin concentration (MCHC) levels, but the mean corpuscular volume (MCV) and the mean corpuscular haemoglobin (MCH) levels were increased. White blood cells (WBCs) count, neutrophils, eosinophils, basophils and monocytes were increased significantly (p<0.05), while the lymphocytes were decreased. Also, carbofuran exposure caused a significant (p<0.05) increase in aspartic aminotransferase (AST) and alanine aminotransferase (ALT) and a significant (p<0.05) decrease in alkaline phosphatase (ALP) activity. The results obtained showed a significant (p<0.05) increase in plasma glucose, total lipids, urea and creatinin levels, but the total protein, albumin concentration and globulin levels were decreased (p<0.05) significantly and consequently A/G ratio also decreased. Carbofuran caused many genotoxic and morphological alterations in erythrocytes such as formation of micronuclei (MN), echinocytes, acanthocytes, tear like drop cells, microcytes and erythrocytes with vacuolated cytoplasm and pale nucleus. The exposed groups have shown significant variations in frequencies of MN and altered erythrocytes in comparison to control group, and these frequencies increased significantly (p<0.05) with the increase of carbofuran concentration. Therefore, current results present a clear evidence of the response of C. gariepinus to carbofuran and allow us to consider that C. gariepinus as a good bioindicator to reflect the toxicity and the genotoxic potential of carbofuran that might be released into the aquatic ecosystems.