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Copper acutely impairs behavioral function and muscle acetylcholinesterase activity in zebrafish (Danio rerio)

Haverroth, Gabriela M.B., Welang, Chariane, Mocelin, Riciéri N., Postay, Daniela, Bertoncello, Kanandra T., Franscescon, Francini, Rosemberg, Denis B., Dal Magro, Jacir, Dalla Corte, Cristiane L.
Ecotoxicology and environmental safety 2015 v.122 pp. 440-447
Danio rerio, acetylcholinesterase, acute exposure, adults, animals, aquatic organisms, behavior change, brain, copper, ecotoxicology, gills, heavy metals, liver, locomotion, muscles, oxidative stress, surface water, toxicity
Copper is a heavy metal found at relatively high concentrations in surface waters around the world. Copper is a micronutrient at low concentrations and is essential to several organisms. At higher concentrations copper can become toxic, which reveal the importance of studying the toxic effects of this metal on the aquatic life. Thus, the objective of this study was to evaluate the toxic effects of copper on the behavior and biochemical parameters of zebrafish (Danio rerio). Zebrafish were exposed for 24h at a concentration of 0.006mg/L Cu. After the exposure period, behavioral profile of animals was recorded through 6min using two different apparatuses tests: the Novel Tank and the Light–Dark test. After behavioral testing, animals were euthanized with a solution of 250mg/L of tricaine (MS-222). Brain, muscle, liver and gills were extracted for analysis of parameters related to oxidative stress and accumulation of copper in these tissues. Acetylcholinesterase (AChE) activity was determined in brain and muscle. Results showed acute exposure to copper induces significant changes in behavioral profile of zebrafish by changing locomotion and natural tendency to avoid brightly lit area. On the other hand, there were no significant effects on parameters related to oxidative stress. AChE activity decreased significantly in zebrafish muscle, but there were no significant changes in cerebral AChE activity. Copper levels in tissues did not increase significantly compared to the controls. Taken together, these results indicate that a low concentration of copper can acutely affect behavioral profile of adult zebrafish which could be partially related to an inhibition on muscle AChE activity. These results reinforce the need of additional tests to establishment of safe copper concentrations to aquatic organisms and the importance of behavioral parameters in ecotoxicological studies.