Monitoramento do estresse oxidativo e da atividade da acetilcolinesterase na avaliação da condição fisiológica de peixes do Baixo São Francisco

Abstract

The physiological condition of aquatic organisms may be affected by a variety of environmental factors and can be evaluated by analyzing certain biochemical parameters. Fish species piau três pintas (Leporinus friderici) pirambeba (Serrasalmus brandtii) Sarapó (Sternopygus macrurus) and traíra (Hoplias malabaricus) were captured in the Rio São Francisco in February, April, May and July 2011, near the city of Porto Real do Colégio, Alagoas, where two sampling points were determined geographically. Immediately after capture, the animals were taken to the laboratory where they were anesthetized and killed for the removal of organs, which were stored in plastic tubes and frozen for subsequent biochemical analysis. We determined the activity of the enzyme brain acetylcholinesterase (AChE), catalase and glutathione peroxidase (GSH-Px) in the liver, as well as levels of hydroperoxide and total thiol groups in the liver. AChE was most active in piau três pintas, with less variation over the sampling months between enzymes evaluated. In piau três pintas were also recorded the highest activities of antioxidant enzymes catalase and GSH-Px among species in most months. The concentration of hepatic hydroperoxide were higher in February for the species collected in this month, being the piau three pints that showed the highest levels. Levels of total thiols showed the less variation between sampling months for the four species, when compared to the values of antioxidant enzymes. The evaluated parameters have changed in the sampling carried out in different months, and piau três pintas was the species that showed the highest values found for most of these parameters.