Uso do sistema de fluxo contínuo de água na recria de juvenis de matrinxã (brycon amazonicus spix e agassiz,1829)

Abstract

The matrinxã (Brycon amazonicus) is considered a promising species for fish farming in the Amazon region, for its importance in the local market and its adaptation to the culture environment. The growing phases are crucial for fish farming, by reducing the time for fattening and improve the homogeneity of the batch. The use of high-flow systems is already used for rearing of juveniles in various countries and in Brazil this system facilitates the handling and reduces spending on food and manpower. The aim of this study was to evaluate: the effect of stocking density on performance, water quality and economic indices in the rearing of juvenile matrinxã using the continuous flow of water. The experiment was conducted at Fazenda Agroindustrial Ltda Tambaqui, located on Highway AM - 010 to 143 km, from december 2009 to February 2010. We used a batch of 3,000 juvenile matrinxã homogeneous, with average length 3.03 ± 1.69 cm, acquired the Fazenda Santo Antonio. The design was completely randomized in four stocking densities (T1=50 fish/m3, T2=100 fish/m3, T3=150 fish/m3 and T4=200 fish/m3) with three replications in 12 circular tanks fiberglass 1 m3. We calculated the parameters of growth performance, survival rate, feed conversion, biomass gain, total fuel consumption, specific growth rate and rate of increase in weight. The parameters of water quality analysis: they were electrical conductivity, pH, and temperature and dissolved oxygen, measured daily, with a digital. Samples were collected for analysis of ammonia and nitrite in the laboratory. For the analysis of economic viability were analyzed costs of fixed investments and production, profitability and profitability. The parameters of the performance and water quality were evaluated by analysis of variance (ANOVA) and Tukey test. The results of the live performance showed that the best density was 50 fish/m3. The physical and chemical parameters were within acceptable levels for fish in all treatments, however, one should take into account the concentration of dissolved oxygen in water is a limiting factor in this cropping system. Regarding the results of economic indicators and projections made, the best performance was a density of 200 fish/m3, for rearing of juvenile matrinxã system in continuous flow of water.