title: Biochemical biomarkers in Nile tilapia (Oreochromis niloticus) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends.
abstract: Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1 mL L(-1). The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota.
authors.affiliation: Departamento de Química e Ciências Ambientais, Universidade Estadual Paulista (IBILCE/UNESP), Rua Critóvão Colombo, 2265, CEP 15054-000 São José do Rio Preto, SP, Brazil. lilanog@gmail.com
authors.forename: Lílian
authors.initials: L
authors.lastname: Nogueira
authors.forename: Ana Letícia Madeira
authors.initials: AL
authors.lastname: Sanches
authors.forename: Danilo Grünig Humberto
authors.initials: DG
authors.lastname: da Silva
authors.forename: Vítor Cid
authors.initials: VC
authors.lastname: Ferrizi
authors.forename: Altair Benedito
authors.initials: AB
authors.lastname: Moreira
authors.forename: Eduardo Alves
authors.initials: EA
authors.lastname: de Almeida
mesh_terms: D000818:Animals; D056804:Biofuels / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D005742:Gasoline / Q000633:toxicity*; D005880:Gills / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism; D017210:Tilapia / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D056804:Biofuels; D005742:Gasoline; D014874:Water Pollutants, Chemical; D002374:Catalase; D019363:Cytochrome P-450 CYP1A1; D013482:Superoxide Dismutase; D005982:Glutathione Transferase