Efeito de prebióticos sobre os parâmetros hematológicos e imunológicos de tilápia do Nilo (Oreochormis niloticus) em época de inverno

Abstract

Fish farming in southern Brazil is an activity that is in great expansion, as a result of this progress, stress occurs, negatively influencing the immune system of fish due to the intensification of production and the low temperature in the South region. Therefore, alternatives are sought in order to modulate the immune system and increase resistance to stress. Thus, the objective of this research was to determine the effect of diets supplemented with mannan-oligosaccharide and β-glucans on hematological and immunological parameters of Nile tilapia (Oreochormis niloticus). One hundred and eighty animals were weighed (33.21 ± 0.10 g) and separated into batches of 15 fish, distributed in 12 hapas with a volume of 0.6 m3, in 3 masonry tanks. The tilapia were fed for 90 days with a control diet, without prebiotic supplementation (DC), inclusion of 0.2% of MOS (DM), inclusion of 0.2% of β-glucans (DG) and inclusion of 0.1 % MOS + 0.1% β-glucans (DMG), with three replications in a completely randomized design. At the end of the experimental period, there was no effect (P>0.05) of treatments on hematological parameters. However, serum lysozyme concentration increased (P<0.05) in fish fed the DM diet. Likewise, the mucus lysozyme concentration was also higher (P<0.05) in fish fed DM and DG diets when compared to the control. The greatest response in leukocyte respiratory activity was observed in fish fed with DMG (P<0.05). The diet with 0.2% MOS and 0.1% MOS + 0.1% β-glucans showed positive immunomodulatory capacity, the non-specific immune response.