Respiratory Surveillance and Ca²⁺-ATPase Enzyme Activity Studies of <i>Clarias gariepinus </i>Exposed to Acute Toxicity of Cyanide

Abstract

ABSTRACT. Potassium cyanide, a highly contaminating and toxic aquatic ecosystems pollutant was investigated for acute toxicity on the freshwater fish Clarias gariepinus. Its effect on the Ca 2+ -ATPase activities in the liver, gills, muscle and intestinal tissues and oxygen consumption index was studied. Short-term toxicity test was carried out by static renewal bioassay test over a 96 h period using a lethal concentration (LC 50 ) value of 0.361mg/mL. Potassium cyanide was highly toxic to the animal tested. Results reveal that normal respiratory activity (O 2 consumption) of the fish was significantly affected and there was significant decreased in the Ca 2+ -ATPase activities at the end of exposure periods (24, 48, 72 and 96 h). Correlation analysis reveals a strong relationship between oxygen consumption index and ATPase enzyme activity of Clarias gariepinus exposed to the toxicant. This study reflects the toxic effect of potassium cyanide to the freshwater fish, Clarias gariepinus and suggestion on the possible application of Ca 2+ -ATPase activities and oxygen consumption index as possible biomarkers for early detection of cyanide poisoning in aquatic bodies.