Morphological, haematological and biochemical changes in African catfish Clarias gariepinus (Burchell 1822) juveniles exposed to clotrimazole.

Clotrimazole (CLO) is an imidazole fungicide used in human and veterinary medicine for treating fungal infection. This study evaluated the changes in morphological, haematological and biochemical indices in Clarias gariepinus juveniles exposed to CLO. After the acute exposure, the 96 h LC50 value of CLO determined by probit analysis was 38.79 mgl-1. Based on this value, fish were exposed to sublethal concentrations of 7.76, 3.89, 1.94 and 0.00 mgl-1 (control) of CLO for 21 days and were allowed to recover for 7 days. The result revealed no significant effect on the hepatosomatic index and condition factor of the exposed fish. There were concentration and time-dependent significant decreases in red blood cell (RBC), haemoglobin (Hb), packed cell volume (PCV) and mean corpuscular volume (MCV) with significant increase in the white blood cell (WBC), mean corpuscular haemoglobin concentration (MCHC), and mean corpuscular haemoglobin (MCH) in the exposed group when compared with the control. A mixed trend was observed in the levels of neutrophils, lymphocytes, monocytes and eosinophils. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and glucose values significantly increased, while protein levels were reduced (p < 0.05) throughout the 21-day exposure and the 7-day recovery period. The present research indicated that CLO may have potential toxic effect on non-target organisms especially fish and, therefore, should be monitored in the aquatic ecosystem.

Changes in Brain Acetylcholinesterase and Oxidative Stress Biomarkers in African Catfish Exposed to Carbendazim.

Carbendazim (CBZ) is a widely used, systemic, broad-spectrum benzimidazole fungicide. It is used worldwide against fungal diseases on a wide range of agricultural products and in domestic gardens. The activities of brain oxidative stress biomarkers and acetylcholinesterase (AChE) in juvenile African Catfish Clarias gariepinus exposed to CBZ were investigated. Juveniles were exposed to sublethal concentrations of 0.22, 0.43, and 0.64 mg/L CBZ, which corresponded to 5, 10, and 15% of the 96-h LC50 (the concentration that was lethal to 50% of the test organisms over the first 96 h) of CBZ fungicide for 21 d. Individuals were allowed an extra 7-d recovery period. The brain tissues were sampled and analyzed on days 1, 7, 14, 21, and 28 (including the 7-d recovery period). The results indicated significant concentration-dependent inhibition of the brain AChE activities in all exposed groups. The lipid peroxidation was significantly elevated while the antioxidant enzymes and protein values were significantly inhibited by CBZ exposure. However, the values of catalase on days 7, 14, and 21 were significantly higher than day 1 values. Overall, CBZ altered brain oxidative stress parameters and led to the inhibition of AChE. This fungicide should be used with utmost caution to protect and safeguard fish, ensuring that fish production and survival in the environment remain unaffected.