Biochemical, haematological and morphological variations in juvenile Clarias gariepinus exposed to Carbendazim® fungicide

Abstract

The biochemical, haematological and morphological variations in juvenile Clarias gariepinus exposed to Carbendazim® (methyl-2-benzimidazole carbamate; CBZ), a fungicide effective for the control of fungal pathogens in plants, were determined. The 96 h LC₅₀ value of CBZ determined by probit analysis was 4.33 mg l⁻¹. Fish exposed to 0.22 and 0.43 mg l⁻¹ sublethal concentrations of the fungicide showed alterations in behaviour and morphological indices. There were dose- and time-dependent significant decreases in packed cell volume and mean cellular volume compared to the control. A mixed trend was observed in the number of white blood cells, red blood cell counts and haemoglobin, but the mean cellular haemoglobin volume, mean cellular haemoglobin concentration, and counts of monocytes, basophils and eosinophils, were comparable to those of the control. Exposure of the fish to CBZ significantly increased the number of lymphocytes and glucose, alanine aminotransferase and aspartate aminotransferase concentrations, but significantly reduced protein levels and neutrophil numbers. Consequently, the use and environmental concentrations of CBZ should be closely monitored to safeguard fish health condition in aquatic ecosystems.

Keywords: biochemistry, fish, haematology, morphological indices