Efeitos da exposição ao arsênio sobre juvenis de robalo-peva Centropomus parallelus (Teleostei: Centropomidae) em diferentes salinidades
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Data
2013-04-17
Autores
Cagnin, Renata Caiado
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Universidade Federal do Espírito Santo
Resumo
Arsenic (As) is an metalloid widely distributed in the coastal region of Brazil, in particular in the state of Espírito Santo State, exposing the aquatic animals to its toxicity. Thus, to determine the toxicity of this element on juveniles of the fatsook C. parallelus by evaluating biochemical alterations is extremely important, since this is an important ecological and economical species. Juveniles of C, parallelus were exposed to 0,1, 1,25 and 2,5mg As/L (as As2O3) during 96h in salinities 5 and 25. The effects of As on antioxidant defenses CAT, SOD and GSH in gills, as well as the oxidative damage in lipids (LPO) were avaluated. Furthermore, the activity of acetylcholinesterase (AChE) on brain and the oxygen consumption by respirometry after exposure were verified. With the chemical speciation of arsenite (iAIII) in test solutions, we draw a comparison between the arsenic behavior and the effective uptake by fish on assays. The high toxicity of As for juveniles of C. parallelus was confirmed by inhibition of the antioxidant defense enzimes CAT and SOD, and de decreasing GSH levels, the first line of defense against ROS. The loss of the defense mechanisms led to lipid peroxidation on gills in 1,25mg As/L and 2,5mg As/L treatments. Likewise, there was a decrease in the oxygen consumption, probably due to the deficit on energy metabolism caused by the oxidative stress. Inhibition of the AChE at 0,1mg As/L emphasizes the neurotoxic potencial of arsenic. Speciation shows the predominance of AsIII on the water samples of the bioassays, where a decrease in arsenite after exposure suggests uptake by the organisms. In all tested parameters, there was no variation between both salinities, and even no variations on chemical compounds, indicating the stability of this metalloid over time and tests conditions. This research provides unpublished data about the arsenic effects on C. parallelus, an important marine teleost, and highlights the necessity of biomonitoring As contaminated ecosystems.
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Arsenic , Arsênio , Oxidative stress , Estresse oxidativo , C. parallelus , Robalo-peva