This study will allow us to proceed in response to our investigations on fish exposed to pyrethroids insecticides. Cypermethrin is a pyrethroid insecticide used in aquaculture, in crops, and to control domestic insects and biological vectors. In this study, the B-esterases, enzymes sensitive to aquatic pollution, will be used in addition to genotoxicity approach, as appraisal tools for evaluation of long term damages. In this way, the present study will bring novel set of data on effects of cypermethrin in B-esterases of a Neotropical fish. Therefore, the goals of this study are: 1) investigating the effects of cypermethrin on B-esterases of B. amazonicus, in two experimental approaches in vivo and in vitro and 2)evaluation of the genotoxicity of cypermethrin in the species. To reach the present goals the next experimental procedures will be followed in B. amazonicus exposed to cypermethrin to 96 hours: 1) evaluation of intoxication signals, 2) evaluation of AChE activities in brain and muscle, 3) evaluation of plasma BChE, 4)evaluation of carboxilesterase of liver, gills and gut and 5) evaluation of micronucleus and abnormal nuclear morphology of red blood cells. Forty eight fish will be equally divided into eight 250L tanks and exposed to three cypermethrin concentrations: 20, 40 and 60% of LC50;96h plus control cypermethrin free (n=12). In parallel, an in vitro investigation (kinetic assays and zymography) will be performed with brain AChE and liver CbE of B. amazonicus. These experimental approaches will allow us to appreciate the assumption of B-esterases inhibition and the genotoxicity in B. amazonicus exposed to cypermethrin.
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