950 resultados para Nile Tilapia (Oreochromis niloticus)


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The petrochemical industry represents a sector of intense activity, in constant expansion and great economic importance for Brazil. In order to be used in various human activities petroleum needs to suffer a refinement process that, besides requiring large amounts of water, produces large amounts of wastes, which are discharged in hydric resources. Petroleum is a complex mixture mainly comprised by hydrocarbons, many of them are recognized as toxic chemicals, which are able to induce a considerable environmental pollution. Since water is an important resource for the maintenance of ecosystems and is also the final receiver of effluent discharges of the petroleum industry, there is an imminent need to monitor, constantly, the hydric resources that are influenced by this industrial activity, so that it can be ensured the environmental health. This study aimed, mainly, to analyze the quality of water samples derived from refinement process performed of the largest petroleum refinery in Brazil (REPLAN), in distinct steps of the industry treatment, and waters of rivers associated to its activity. Micronuclei and Nuclear Abnormalities tests were performed in erythrocytes of the fish species Oreochromis niloticus exposed to water samples derived from refinery use and to rivers under the influence of their effluents, in order to evaluate its possible toxic, genotoxic and mutagenic effects. The results obtained show that the treatment carried out by the refinery, during the evaluated periods, was effective, since the substances present in the water samples did not induce significant genotoxic and/or mutagenic alterations in the genetic material of the test organisms. On the other hand, when the substances present in the refinery effluent mix with the ones derived from other industrial activities developed upstream of this industry, the resultant compound, in some periods, presented genotoxic potencial, characterized by a rise of erythrocytic...

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Junto ao Laboratório de Fracionamento de Proteínas, desenvolveu atividades aplicando técnicas eletroforéticas (gel de agarose, eletroforese nativa em gel de poliacrilamida) em amostras de músculos de aves de interesse comercial (frangos, perus e avestruzes), tendo como co-orientador o Prof. Paulo Tadeu Figueira da Faculdade de Medicina Veterinária, PUC/PR - Toledo, onde desenvolveu atividades de análise de géis de eletroforese. Aplicou as técnicas de eletroforeses citadas em amostras de músculos e soro sanguíneo (em andamento) de tilápias (Oreochromis niloticus), bem como desenvolveu atividades de análises computacionais (VDS – PHARMACIA) e estatísticas (ASSISTAT) nos dados obtidos, resultando na participação em 7 congressos com apresentação de trabalhos. Cursou a disciplina de Genética, como aluno especial, junto à turma de Licenciatura em Ciências Biológicas, num total de 8 créditos, sendo aprovado com média 7,2

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Water is an essential factor in maintaining the vital functions of living beings. We have observed a growing commitment of quality, are due to pollution from many sources and even entire watersheds, whether for industrial waste, sewage, or for substances used in farming such as pesticides, herbicides and fertilizers. Nickel is the 24th most abundant element on earth, is a heavy metal that, in the form of chloride, is a proven genotoxic and mutagenic. Due to its industrial use, there was considerable increase of its concentration in surface sediments. Fish combine characteristics that make them excellent experimental models for aquatic toxicology studies, which are particularly usable as warn about the potential danger of chemicals or the possibility of environmental pollution. Due to impaired water quality and the few published studies relating the nickel with the tissue change, this study aimed at assessing the consequences of the presence of nickel in the aquatic environment. For this analysis, we used individuals of Oreochromis niloticus, exposed for 96 hours at three different concentrations of nickel dissolved in water compared to a control group. After exposure, the gills were removed and these were analyzed by ultramorphological, histological and histochemical analysis. The results indicate that all concentrations used in the experiment altered the histophysiology of exposed individuals. We observed the following changes: rupture of paviment cells, thus resulting in bleeding, loss of microridges surface of these cells and epithelial loss in the gills of all animals in all treatments with nickel chloride, the histochemical analysis showed non-proliferation of chloride cells. However, there was a dose-dependent increase of mucus cells in all animals. Therefore, nickel has toxic potential to fish, from the smallest concentration used up to twice as permitted by law, indicating... (Complete abstract click electronic access below)

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The activities of 7-ethoxyresorufin-O-deetylase (EROD), 7-benzyloxyresorufin-O-debenzylase (BROD), 7-pentoxyresorufin-O-depentilase (PROD), and glutathione S-transferase (GST) were measured in Nile tilapias exposed for 7 days of 5 and 15 μg/L 17 β-estradiol. EROD and GST activities were unchanged. PROD activity increased in animals exposed to the higher dose of the hormone, while BROD was increased after 7 exposure days to both doses of the compound. These results indicate the usefulness of these enzymes as biomarkers for 17 β-estradiol exposure.

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The knowledge of how animals deposited chemical components as water, protein, fat and ash in the carcass is importance for the formulation of a balanced diet, allowing maximum performance with a low environmental impact. So, the study was carried out to evaluate the influence of different tilapia strains (Chitralada, Commercial, Red and Universidade Federal de Lavras [UFLA]) on the deposition of bodily chemical components in the carcass. The bodily components analyzed were water, protein, fat and ash. For the determination of the bodily chemical deposition curves by age, the exponential, Brody, logistic, Gompertz and von Bertalanffy models were adjusted. The Commercial and UFLA strains deposited water at a faster speed (P<0.05) compared with the remaining strains. As for protein, the Red strain had a lower estimated maturity weight (49.37 g), and was more precocious (202 days) with regard to maximum deposition in comparison to the other strains (Chitralada, UFLA and Commercial) in which there was an estimated maturity weight of 231.5 g and maximum depositionfor 337 days. There were no differences (P>0.05) for the logistic model parameter between Red, UFLA and Commercial strains for fat, which presented a maximum fat deposition (0.23 g) at 310 days of age. Regarding ash deposition, the Commercial strain presented a higher maximum deposition (0.10 g) at 337 days, occurring later than the other strains that presented maximum deposition (0.033g) at 254 days of age. Thus, it was concluded that the genetic strains evaluated differ in chemical deposition curves of water, protein, fat and ash.