Abstract
The objective of this study was to evaluate the effect of commercial formulation of triazophos on esterase activity in the liver, kidney, brain, blood and muscles of Catla catla, Labeo rohita and Cirrhinus mrigala fingerlings. Toxicity of triazophos was tested in the fingerlings of major carps following static bioassay and probit analysis. The fingerlings of C. catla, L. rohita and C. mrigala were exposed to three sub lethal concentrations: 1/5th (0.97, 0.48, 0.32), 1/10th (1.33, 0.66, 0.44) and 1/15th (0.12, 0.06 and 0.04 mg/L) part of LC50 of triazophos in three replicates for 8 weeks. The activity of cholinesterases (acetylcholinesterase and butyrylcholinesterase) was significantly inhibited even at the lowest concentrations of triazophos in brain, blood, gills, muscle, kidneys and liver. It has been concluded that cholinesterases in liver were more inhibited compared to those of brain, kidney and muscles.