Adição do óleo essencial de Lippia alba (Mill) N. E. Brown na dieta do jundiá: análise do crescimento e da resposta antioxidante

Abstract

Fish become more susceptible to stress and, consequently, to the onset of disease with the intensification of rearing. In an attempt to minimize this problem, farmers use agrochemicals that, besides harming the environment, can also affect producers and consumers health. The essential oil (EO) of Lippia alba may be a natural alternative since it has several effects that can reduce the physiological changes resulting from stress inherent in aquaculture. The influence of five diets containing L. alba EO (0, 0.25, 0.5, 1.0 and 2.0 mL of EO per kg of diet) on growth and antioxidant response in juvenile silver catfish was evaluated. After a feeding period of 60 days, the silver catfish were weighed and measured individually, and euthanized for sampling of brain, gill, liver, kidney and muscle. The oxidative stress biomarkers, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and non-protein thiols groups (NPSH), were determined. Growth parameters were not affected by the diet containing L. alba EO. As for biomarkers of oxidative stress, lipoperoxidation (LPO) evaluated through TBARS and LOOH was reduced by the EO in the gills, liver, kidney and muscle of silver catfish; no effect was observed in the brain. The diet with the EO improved the activity of antioxidant enzymes: SOD, CAT, GPx, GST and NPSH levels in the brain; SOD, GR and GST in the gills; CAT, GR and NPSH levels in the liver; CAT, GR and NPSH levels in the kidney; and SOD, GPx and NPSH levels in the muscle. These results indicate that L. alba EO does not interfere with growth, decreases LPO levels and increases antioxidant enzymes activities in most tissues evaluated, and thus may be added to silver catfish diet to increase the antioxidant response.