Associação de frutooligossacarídeo e ácido orgânico na alimentação da Tilápia do Nilo

Abstract

Intensive fish production systems impose stress on animals, which negatively affects growth and the immune system, making them susceptible to disease. In order to increase disease resistance, the use of food additives such as prebiotics and organic acids emerge as an important tool to improve the performance and immune activity of fish. Given the above, the objective was to evaluate the potential of the association of a prebiotic (FOS) and citric acid as a promoter of growth and resistance to stress in Nile tilapia (Oreochromis niloticus). One hundred and forty-four juveniles of Nile tilapia (47.5 ± 3.89 g) were separated into homogeneous batches and distributed in twelve polyethylene boxes (250 L) with an average temperature of 22.50 ± 2.10ºC, composing a design completely randomized with four treatments (T1= 1.5% citric acid, T2= 1.5% citric acid + 0.2% FOS, T3= 0.2% FOS, T4= Control) and three replications, fed twice a day for 48 days (8:00 h and 17:00 h) until apparent satiety. At the end, the first biological collection was carried out, for the second collection the animals were fed for another 10 days with dietary cortisol (400 mg of hydrocortisone/kg of diet), the second part of the biological material was collected and the hematological and immunological parameters were evaluated. The association of citric acid + FOS showed a higher number of monocytes (P<0.05) at time 1 and a higher mean corpuscular volume in the diet with FOS in relation to the control diet. After cortisol, the analysis of hematocrit and number of lymphocytes were respectively higher and lower significantly for the treatment with FOS in relation to the control diet (P<0.05). The analyzes after dietary supplementation with cortisol corroborate the results presented in the literature in organisms submitted to or under stress. The treatments did not have immunomodulatory capacity and resistance to stress.