The use of a flocculant additive and its effect on biofloc formation, nitrification, and zootechnical performance during the culture of Pacific white shrimp Penaeus vannamei (Boone, 1931) in a BFT system

Abstract

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.