Efeito da frequência de adição de Brachionus plicatilis na fase berçário de Litopenaeus vannamei em sistema de bioflocos

Abstract

The BFT system can provide an increase in the zootechnical indexes in comparison with the conventional culture system, since it allows working with high stocking densities, and with less water exchange. In addition, this system provides shrimp with better immune response and better control of water quality, but in terms of nutrition, bioflocs are deficient in methionine, PUFA and HUFA. One way to improve the nutritional quality of this microbial floc and consequently the performance of the cultured organisms, is the supplementary addition of microorganisms nutritionally rich in amino acids and fatty acids to the system. The rotifer B. plicatilis fits these requirements, as it has the capacity to tolerate a wide range of salinity, it has slow mobility and rapid reproduction, and these characteristics contribute to the use of this organism as supplementary food for the initial stages. The objective of this work was to evaluate the effect of adding B. plicatilis on L. vannamei postlarvae culture in biofloc system. The experiment lasted 42 days with four treatments: BFT (biofloc no addition of B. plicatilis); BFT-1F (frequency of adding B. plicatilis on the 1st day of culture); BFT-2F (frequency of adding B. plicatilis on the 1st and 10th day of culture) and BFT-4F (frequency of adding B. plicatilis on the 1st, 10th, 20th and 30th day of culture) each in triplicate. The experimental units with 40 L of useful volume and stocking density of 3000 animals m-3 in experimental units. Water quality variables are not shown differences between treatments. However, the variables of zootechnical performance in BFT-4F treatment show the best final weight (0.73g), yield (1.88kg/m3) and specific growth rate (14.31% day). In relation to the plankton community, the phylum that had the greatest growth were Chlorophyte and Protozoa. For Vibrio density, there was a reduction at the final time in relation at initial experimental time, the BFT-2F treatment with the largest number of colonies at the end. Therefore, the addition of rotifers in four frequencies in the biofloc system becomes a good option for the nursery of L. vannamei.