Sulfated polysaccharides in diets for nile tilapia (Oreochromis niloticus) in the initial growth phase

Abstract

This study had the objective of evaluating the performance of Nile tilapia, in initial growth phase, with the supplementation of fucoidan, extracted from brown algae, at 30 days of rearing. The experiment was conducted for a period of 30 days. We used 216 Nile tilapia fingerlings distributed in to twelve 60 liter tanks, in a completely randomized design, totalizing four treatments and tree replicates. The fingerlings were supplemented with powdered sulfated polysaccharide extract at the levels of 0%, 0.5%, 1.0% and 1.5%. During the experimental period, two samplings were performed (initial and final) to measure zootechnical performance, muscle histology and blood plasma chromatography. The data were submitted to analysis of variance at a level of significance of 5%. The performance variables muscle fiber diameter frequency and fucose plasmatic concentration were not significant among the treatments (P>0.05). It was possible to identify fucose in the blood plasma of the animals, proving its efficiency in breaking the α-(1-3) bonds of the polysaccharide, thus absorbing this component. The histological analysis showed that there was a higher percentage of hypertrophic growth of the muscle fibers, given that, in all treatments, the diameter class >50 μm prevailed (P<0.05). In conclusion, the sulfated polysaccharide fucoidan, used in diets for Oreochromis niloticus with 30 days of rearing, was not effective in increasing performance parameters and muscle growth.