Avaliação de biomarcadores bioquímicos em tilápias (Oreochromis niloticus) expostos a óleo diesel e biodiesel
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Data
2013-05-22
Autores
Bedin, Bruno Henrique [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Dentre os contaminantes ambientais mais produzidos no mundo estão os derivados do petróleo, que atingem e contaminam os ambientes aquáticos. Sendo o petróleo uma forma de energia não renovável, alternativas renováveis e menos poluentes como o biodiesel vêm sendo pesquisadas. Entretanto, apesar de ser considerado menos poluente, mais biodegradável e produzir menos gases de efeito estufa durante a queima, pouco se sabe ainda sobre os potenciais efeitos tóxicos do biodiesel para a biota aquática. Estes efeitos podem ser avaliados por meio da análise de biomarcadores de contaminação, tais como alterações metabólicas na atividade de enzimas de biotransformação e em parâmetros de estresse. Neste trabalho foram analisados os efeitos de duas concentrações (0,1 e 0,01 mL/L, com manutenção do tratamento a cada 5 dias) do biodiesel puro (B100) e da mistura de 20% de biodiesel com diesel de petróleo (B20), em comparação com os efeitos do diesel de petróleo contendo 5% de biodiesel (B5) e animais não expostos a nenhum dos combustíveis, em fígado e brânquias de tilápias do Nilo (Oreochromis niloticus) expostas por 15 e 30 dias. Foram avaliadas as atividades das enzimas de biotransformação etóxiresorufina-O-deetilase (EROD) e glutationa S-transferase (GST), das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT) glutationa peroxidase (GPx) e níveis de peroxidação lipídica por meio da quantificação do produto malondialdeído. Testes de toxicidade foram também realizados para se estabelecer valores de LC50 para cada contaminante, de forma a melhor compararmos os efeitos dos contaminantes, os quais mostraram que o B5 foi o composto mais tóxico, seguido do B20 e em seguida o B100. Animais expostos ao B5 e ao B20 por 15 dias tiveram a atividade da EROD aumentada e suas enzimas...
Among the environmental contaminants most produced in the world are derived from petroleum, which reach and contaminate aquatic environments. Because oil is a form of non-renewable energy, renewable and less polluting alternatives such as biodiesel have been researched. However, despite being considered less polluting, more biodegradable and produce less greenhouse gases during the burning, little is known about the potential toxic effects of biodiesel on aquatic biota. These effects can be evaluated through the analysis of biomarkers of contamination, such as changes in metabolic activity of biotransformation enzymes and stress parameters. In this study, we analyzed the effects of two concentrations (0.1 and 0.01 mL / L, with maintenance treatment every 5 days) of pure biodiesel (B100) and the mixture of 20% biodiesel with petroleum diesel (B20), compared with the effects of diesel oil containing 5% biodiesel (B5) and animals not exposed to any fuel in liver and gills of tilapia (Oreochromis niloticus) exposed for 15 and 30 days. We evaluated the activities of biotransformation enzymes etóxiresorufina-O-deetilase-(EROD) and glutathione S-transferase (GST), of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation levels through quantifying the product malondialdehyde. Toxicity tests were also conducted to establish LC50 values for each contaminant in order to better compare the effects of contaminants, which showed that B5 was the most toxic compound, followed by B20 and then B100. Animals exposed to B5 and B20 for 15 days had increased EROD activity of and their antioxidant enzymes significantly inhibited, which was not observed in animals exposed to B100. Nevertheless, despite the inhibition observed in the antioxidant defenses, the... (Complete abstract click electronic access below)
Among the environmental contaminants most produced in the world are derived from petroleum, which reach and contaminate aquatic environments. Because oil is a form of non-renewable energy, renewable and less polluting alternatives such as biodiesel have been researched. However, despite being considered less polluting, more biodegradable and produce less greenhouse gases during the burning, little is known about the potential toxic effects of biodiesel on aquatic biota. These effects can be evaluated through the analysis of biomarkers of contamination, such as changes in metabolic activity of biotransformation enzymes and stress parameters. In this study, we analyzed the effects of two concentrations (0.1 and 0.01 mL / L, with maintenance treatment every 5 days) of pure biodiesel (B100) and the mixture of 20% biodiesel with petroleum diesel (B20), compared with the effects of diesel oil containing 5% biodiesel (B5) and animals not exposed to any fuel in liver and gills of tilapia (Oreochromis niloticus) exposed for 15 and 30 days. We evaluated the activities of biotransformation enzymes etóxiresorufina-O-deetilase-(EROD) and glutathione S-transferase (GST), of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation levels through quantifying the product malondialdehyde. Toxicity tests were also conducted to establish LC50 values for each contaminant in order to better compare the effects of contaminants, which showed that B5 was the most toxic compound, followed by B20 and then B100. Animals exposed to B5 and B20 for 15 days had increased EROD activity of and their antioxidant enzymes significantly inhibited, which was not observed in animals exposed to B100. Nevertheless, despite the inhibition observed in the antioxidant defenses, the... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Toxicologia ambiental, Biodiesel - Toxicologia, Combustiveis diesel - Toxicologia, Tilápia (Peixe) – Efeito da poluição da água, Marcadores biologicos, Ecossistemas aquáticos, Environmental toxicology
Como citar
BEDIN, Bruno Henrique. Avaliação de biomarcadores bioquímicos em tilápias (Oreochromis niloticus) expostos a óleo diesel e biodiesel. 2013. 55 f. Dissertação (mestrado) - Universidade Estadual Paulista Julio de Mesquita Filho. Instituto de Biociências, Letras e Ciências Exatas, 2013.