Concentration related responses of chlorpyriphos in antioxidant, anaerobic and protein synthesizing machinery of the freshwater fish, Heteropneustes fossilis

► Effects of chlorpyriphos on profiles of catalase (CAT), lactate dehydrogenase (LDH), DNA, RNA and protein of the catfish, Heteropneustes fossilis were studied. ► Chlorpyriphos inhibited activities of enzymes and macromolecular contents in different tissues. ► Reductions in biochemical constituents suggest concentration-dependent impairment in antioxidative, anaerobic and protein synthesizing capacity of the fish.