Impact of alphamethrin on biochemical parameters of Channa punctatus.

Impact of alphamethrin (synthetic pyrethroid) on profiles of lactate dehydrogenase (LDH), catalase (CAT), DNA, RNA and protein in liver, brain, gill and skeletal muscle of the freshwater food fish Channa punctatus were investigated. Exposure of sublethal concentration of alphamethrin (0.018 ppm for 14 days) increased the activity of LDH in liver (1.8 fold), brain (1.4 fold), gill(1.6 fold), and skeletal muscle (2.2 fold) of the fish. However, it significantly decreased the activity of CAT in the tissues of liver (54%), skeletal muscle (52%), gill (51%) and brain (49%) of the fish. Similarly, DNA (skeletal muscle (36%), liver (30%), brain (28%) and gill (25%)) RNA (liver (42%), brain (32%), gill (35%) and skeletal muscle (45%)) and protein content (45%), brain (42%), gill (36%), and skeletal muscle (27%)) declined in different tissues of the fish exposed to alphamethrin. Maximum increase in the level of LDH was in skeletal muscle (2.2 fold) and minimum in brain (1.4 fold). Maximum reduction in CAT profile was in liver (54%), and minimum in brain (49%). Declines in DNA was maximum in skeletal muscle (36%) and minimum in gill (25%) whereas RNA and protein content were maximum in liver (42% and 45% respectively) and minimum in skeletal muscle (45% and 27% respectively). Alphamethrin was toxic to the freshwater fish due to its inducing effect on anaerobic enzyme (LDH) and inhibitory effect on antioxidant enzyme (CAT), DNA, RNA and protein. This reflected alphamethrin associated increase in anaerobiosis and decrease in oxidative defense and impairment in protein synthesizing capacity of C. punctatus. Further, induction in LDH and reduction in CAT and protein profile may be used as biomarker of alphamethrin toxicity in fish.