Risk assessment of malathion on health indicators of catfish: Food and water security prospective research

Specimens of Heteropneustes fossilis were treated with various levels of malathion and its 96 h LC₅₀ value was determined. The effects of sub-lethal concentrations of insecticide on hematological and biochemical profile of Heteropneustes fossilis were also registered. The 96 h LC₅₀ value obtained was 8.81 mg/l. Exposure of sub-lethal doses (0.44, 0.88 and 1.76 mg/l which are 5, 10 and 20% of the LC₅₀) of malathion to Heteropneustes fossilis for 3 weeks demonstrated that the toxicant had a detrimental effect on the blood profile of fish. Blood cell (Erythrocyte and leucocytes) counts (from 1.66 to 1.44 cell × 10⁶ × mm³ and 37.93 to 30.24 cell × 10³ × mm³; respectively), haemoglobin (Hb) level (from 6.21 to 3.54 g/dl) and haematocrit (Ht) estimates (from 34.26 to 30.52%) were reduced in the fishes exposed to malathion. Elevated level (from 46.25 to 92.45 mg/100 ml) of glucose and decreased quantity (29.95 to 24.25 g/dl) of protein in plasma was registered. Glycogen content in muscle and liver was also decreased. The activity of enzymes glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) were high in the fish treated with pesticide. The possible causes for variations in the different parameters were identified and discussed.