Acute toxicity of calcium hypochlorite (65% chlorine disinfectant) on the liver, brain, and gill of Clarias gariepinus fingerlings (Burchell, 1822)

Abstract

The acute toxicity of Calcium Hypochlorite was investigated on the water quality and histopathology of liver, brain and gill of Clarias gariepinus fingerlings. Fish with average weight and length of 5.5 ± 0.8g and 7.8 ± 0.5cm were stocked at 10 fish per tank and fed with 45% crude protein diets. The experimental fish was exposed to a photoperiod of 12 hours daylight and 12 hours darkness. After the range finding test, the fingerlings were exposed to test concentrations of treatments 0.000 mg/L (A), 0.011 mg/L (B), 0.033 mg/L (C), 0.055 mg/L (D) and 0.077 mg/L (E) and was replicated trice. The Lethal Concentration value (LC50) for the disinfectant was 0.033mg/L. Behavioural changes such as erratic swimming, frequent jumping and gasping for air at the surface was observed in the exposed fish. Histopathology of the brain showed different stages of spongiosis and necrosis; gills showed thickening of the lamellae and necrosis while the liver showed varying congestion in the exposed fish. The observed changes in behaviour and histopathology were normal in the control fish and increased with increase in concentration of disinfectant to the exposed fish.