Malathion induced hematological and biochemical changes in the Indian catfish Heteropneustes fossilis.

The acute toxicity and effects of duration of sublethal exposure to malathion were determined in the Indian catfish (Heteropneustes fossils). Fish exposed to the pesticide for 2, 6, 12, 48, and 96 hr showed muscle glycogenolysis with concomitant hyperglycemia at all intervals; hepatic glycogen was unaffected. Malathion was also associated with hypochloremia at 2 and 6 hr and hyperchloremia at 48 and 96 hr; blood chloride concentration was unaffected at 12 hr. Fish developed erythropenia and leukopenia; lowered hematocrit and hemoglobin content and hypercoagulability of blood were also observed. The data show that homeostatic and hemostatic mechanisms are disturbed after malathion treatment and could be helpful for evaluating pesticide toxicosis in fish.