Acute toxicity, behavioral response and biochemical composition of blood of common carp, Catla catla (Hamilton) to an Organophosphate insecticide, Dimethoate.

In the present investigation the acute toxicity bioassay, behavioral response and biochemical parameters of blood of Catla catla to toxicity of an Organophosphate insecticide, Dimethoate were carried out in a static renewal system. It is evident that no mortality of Catla catla was recorded at 20.5mg/l Dimethoate up to 24 hrs. of exposure. At concentrations of 23.0, 23.5 and 24.0mg/l of Dimethoate 100% mortality of Catla catla was recorded at three different concentration of Dimethoate viz., 23.0mg/l, 23.5mg/l and 24.0mg/l in 96 hrs. of exposure. The LC50 values of Dimethoate at various exposure times were 21.0mg/l for about 84 hrs; 21.5mg/l for 72 hrs; 22.0mg/l for about 60hrs; 22.5mg/l for 48 hrs; 23.0mg/l for 48 hrs; and 23.5mg/l for 24 hrs. The Catla catla showed behavioral alterations against Dimethoate intoxication viz, uncoordinated movements, erratic swimming, convulsions, excess mucus secretion, decreased opercular movements, loss of balance, drowning and change in body pigmentation, muscle fasciculation, moribund lethargy, refusal of feeding and respiratory distress. These symptoms became more apparent with increase in duration of exposure at all test concentration of Dimethoate. The glycogen content, total proteins and total lipids decreased in the blood of Catla catla under the toxicity of Dimethoate whereas the levels of total free sugars and total free amino acids increased. K e y w o r d s LC50, Dimethoate, Catla catla, Toxicity, Serum composition