Análise de qualidade de água na recria de tilápia do nilo (Oreochromis niloticus) em sistemas bioflocos e recirculação de água

Abstract

The Nile tilapia (Oreochromis niloticus) is a species of fish researched and produced all over the world, because it has characteristics that stand out in aquaculture. The Recirculating Aquaculture System (RAS) is an intensive system that, through various treatments, can make aquaculture effluent return to the system, like clean water, needing to recover losses by evaporation. Biofloc Technology (BFT) aims at balancing a dense microbial community, where these microorganisms form aggregates that improve water quality and can still serve as food. By using minimal water renewal, both systems can remain sustainable for long periods. Because the two systems enable high crop densities, the control of water quality variables determines the success of the activity, requiring investments in production and the presence of qualified professionals. The work was carried out at the Fisheries Laboratory of the Federal University of Southern Frontier - campus Laranjeiras do Sul, with the objective of evaluating the most efficient system, performing periodic water quality analyzes. A total of 270 juveniles of tilapia, divided into 18 boxes of 50 L, were fed the diets containing different protein concentrations (28, 33, 38%), with three replicates each, aiming to observe the nitrification capacity in the systems. Multivariate analysis of variance (ANOVA), normality test and if necessary the Tukey test were performed. Through this work, even with mortality, it was possible to observe that both systems succeeded in keeping the water quality variables at acceptable levels for the species.