Avaliação de biomarcadores bioquímicos e genotóxicos na espécie Serrasalmus brandtii (Lutken, 1865) capturada no reservatório Itaparica - PE-BA

Abstract

Aquatic environments are ecosystems that most affected impacts caused by anthropogenic action, since it is the final compartments of various products produced by human activity. This study evaluated the fish specie Serrasalmus brandtii (pirambeba), collected at two sites in the Itaparica reservoir (Brazil) during March/12 to January/2013 through biochemical and genotoxic biomarkers. Around the reservoir resettlement areas exist with agricultural practices using agrochemicals. Thus, the study aimed to use S. brandtii as specie sentinel for this region of the Sao Francisco river. There was no significant difference in the physicochemical parameters measured such as temperature and dissolved oxygen over the sample period. Among the morphological parameters, the masses of the specimens varied between sampling period. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were quantify on the brain and muscle specimens collected from the two sites. Brain AChE from pirambeba collected at site 1 showed a significant decay in specific activity over the study period, however protein content did not show the same profile. Brain BChE specific activity had significant variation during the sampling period. On the contrary, pirambeba collected at site 2 showed no significant difference in the brain AChE specific activity and protein content. Brain BChE of these specimens showed significant variation on the specific activity values. On muscle tissue, pirambeba collected at site 1 showed significant variation in the values of AChE specific activity as well as on the protein content during the sample period. BChE specific activity on the muscle also had significant variation. Pirambeba collected at site 2 showed significant variation on muscle AChE specific activity and protein content values over the analyzed period. For muscle BChE activity,values, the results showed pattern similar to the one observed on site 1. Genotoxicity assays were performed on pirambeba erythrocyte cells collected at two sites. The results showed frequency of micronuclei (MN) and significant variation between the mean frequencies of MN over the study period was observed. Nuclear abnormalities (NA) were also analyzed and the results indicated that pirambeba the site 1 had higher nuclear abnormalities frequencies than the pirambeba from site 2. The Comet assay indicated that majority of erythrocyte nuclei analyzed from both sites shown class 1damage indicating slight DNA damage. In vitro studies were also performed for the characterization of brain AChE from pirambeba and kinetic assays showed values of 0.324 ± 0.04 mmol /L and 0.709 ± 0.014 mmol / min-1.mg protein for the apparent kinetic constants Kmapp and Vmáxapp respectively. Brain AChE inhibitory assays showed that muscle AChE (0.362±0.2 μM) was more sensitive to carbamate eserine that brain AChE (0.887 ± 0.1 μM) AChE and when compared brain AChE between eserine (0.887 ± 0,1μM) and glyphosate (2,276 ± 0,02μM), there was a greater sensitivity for brain AChE with eserine. We conclude that among the biomarkers genotoxic tested, the results showed that the MN test was considered the most sensitive; S. brandtii specie can be a specie sentinel for the submedium San Francisco region, since was present in all samples of the river, even during the most severe period of drought and low water level, but also by having a direct relationship with the AChE activity and forming MN.