Potencial imunoestimulante do óleo essencial de Menthapiperita na dieta do tambaqui, colossoma macropomum

Abstract

Animal diseases in fish farms has increased the demand for preventive measures, such as vaccines and supplemented diets with immunostimulatory substances. This study aimed to evaluate the immunostimulatory potential of the essential oil of Menthapiperita for tambaqui (Colossomamacroponum). The animals were divided into 12 tanks of 500L (20 fish / tank) and submitted to treatments with three replications of 0; 0.5; 1.0; 1.5% oil inclusion levels, twice a day (9 and16h). After thirty days, five fish from each treatment were anesthetized with benzocaine (0.1 g/L) for blood collection and evaluation of hematological and biochemical parameters, characterizing the period before the bacterial challenge. Blood parameters evaluated were: erythrocytes count, hematocrit, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration; glucose, protein, triglycerides, albumin, urea and cholesterolplasmaconcentrations. These were determined after 30 days of feed and 7 days after challenge with Aeromonashydrophillacontaining 1.5 x108 CFU / mL. The results showed that the inclusion of M. piperita oil in the diets did not affect the production parameters and the fish survival.The Hb concentration increased (P<0.05) in animals fed with diets with 0.5 and 1.5% of essential oil; after challenge, Hb fell significantly in the 1.5% group. The tambaqui’smean corpuscular volume (MCV) remained the same with the oil in the diet, however after challenge decreasedin the group fed by 1.0%. Mean corpuscular hemoglobin concentration (MCHC) diminished at 0% and 1.5% after challenge.Protein levelsincreased (P<0.05) in levels 0 and 1.5% after challenge.Albumin concentration showed increase (P<0.05) after challenge for 0 and 1.0% of oil in the diets. Increased cholesterol levels presented significantly increases with the oil in the diet; and after challenge, just the control group remained increased. Triglycerides levels were lower in fish fed by diets with 0.5% of oil; and after challenge, showed increased levels at 0, 0.5 and1.5%. The essential oil of M.piperitaup to 1.0% of inclusion in the diets, promoted tambaqui’s physiological responses, and could be recommended as immunostimulant product