Missileny Xavier

Shrimp farming in the Biofloc Technology System (BFT) is already considered an alternative to the traditional culture. The bioflocs maintain the water quality and can be used as a food supplement for shrimp. The Pacific white shrimp Litopenaeus vannamei forms the basis for most of the production in BFT. However, its culture is limited by the low temperatures. Thus, the BFT culture potential of native species, such as the pink shrimp Farfantepenaeus brasiliensis, should be considered. The present study aimed to compare the cultures of F. brasiliensis and L. vannamei in the grow-out phase in the BFT system. The experiment comprised two treatments: (FB), grown out of F. brasiliensis, and (LV), grown out of L. vannamei. The study lasted 70 days and was conducted at the Marine Station of Aquaculture at the Federal University of Rio Grande, Rio Grande do Sul State, Brazil. The stocking density was 100 shrimp/m² for both species. The shrimp were fed twice a day with commercial food. The physicochemical parameters of the water were monitored throughout the experimental period. The results showed that all physicochemical parameters of the water remained within the tolerated limits for both species. However, during the growth phase in the BFT, it was observed that the L. vannamei shrimp showed a better zootechnical performance than F. brasiliensis. The results indicate that L. vannamei has a higher capacity to catch bioflocs as supplementary food, demonstrating a better response of that species to the BFT system in the grow-out phase compared to F. brasiliensis.

Biofloc technology is a culture system that intensively uses microbial communities. Most bacteria can form aggregates around organic or inorganic surfaces. The high adsorption capacity, surface area, and flocculant properties of clay minerals make these compounds good candidates to stimulate biofloc formation, increase bacterial biomass, and improve nitrification. The objective of this study was to evaluate the addition of clay minerals to biofloc formation and its influence on the microbial community, nitrification, and zootechnical performance of Penaeus vannamei cultivated in a biofloc technology system. Experiment 1 involved the following treatments: control (without adding clay minerals), 10, 50, and 100 mg L-1, applied daily in the water. The treatments in experiment 2 were: control without product and inoculum, control without product and with inoculum, 50 mg L-1 clay mineral without inoculum and 50 mg L-1 clay mineral with inoculum. Both experiments with a density of 400 ind m-3. NO2 levels, total suspended solids, turbidity, differed significantly (P < 0.05) between treatments in experiment 1 and zootechnical performance parameters, where higher flocculant concentrations negatively affected these indices. In experiment 2, statistical differences were verified for NH3 and NO2 concentrations and the proximate composition of the bioflocs (P < 0.05), the addition of the inoculum of bioflocs influenced these results. In summary, the addition of clay minerals influenced biofloc formation, proximal composition, and the zootechnical performance of the cultivated shrimp but did not affect the abundance of microorganisms and nitrification.