Larvicultura de tambatinga (Colossoma macropomum x Piaractus brachypomus) em diferentes densidades de estocagem em sistema de bioflocos e de água clara

Abstract

The realization of larviculture in biofloc, as well as studies aiming to determine the recommended stocking density to achieve good productive and financial performance are still incipient. Thus, the present study aimed to evaluate the effect of different storage densities of Tambatinga post larvae on the biofloc and clear water system, analyzing the parameters of water quality, zootechnical performance, survival and to perform an economic analysis of the implantation of these systems. There were used 1080 post-larvae with initial average weight of 0.00072g and 6.02 mm in length. The post larvae they were submitted to the following treatments: clear water system and biofloc system. Each of the treatments contained three densities 10, 20 and 30 postlarvae / liter with 3 replications, totaling 18 experimental units. The fish were fed ad libitum with commercial meal with 40% CP. Biometrics were performed on days 0, 3, 6, 9 and 12 days of the experimental period and there were four water samples collected for pH, total ammonia, toxic ammonia and alkalinity analysis. The statistical analysis was performed by analysis of variance (ANOVA) and when significant means were compared by Tukey test (5%). For the economic analysis, calculations were performed to determine the total cost of production and, at the end of the treatments, were compared using the financial-productive indicator. Significant differences were found in the alkalinity, total ammonia and toxic ammonia analyzes between the biofloc system and clear water. Based on the zootechnical performance there was a significant difference between the stocking densities and also between the systems, being the density 10 in biofloc higher than the others in relation to the weight and length. The survival in density of 30 post larvae/liter in clear water was higher to the other treatments. When analyzing the total cost of production, the biofloc system was about 100 thousand reais higher than that of clear water, but when analyzing the financialproductive indicator the biofloc obtained a better relation, because for each real invested the powders - density 10 and 20 responded about 4.5 and 1.76 times, better than the same densities in clear water, respectively. In addition to improving water quality and reducing environmental impacts due to reduced water use, biofloc also enables better zootechnical indices.