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Pacific white shrimp and Nile tilapia integrated in a biofloc system under different fish-stocking densities

Poli, Moisés Angel, Legarda, Esmeralda Chamorro, de Lorenzo, Marco Antônio, Martins, Mateus Aranha, do Nascimento Vieira, Felipe
Aquaculture 2019 v.498 pp. 83-89
Litopenaeus vannamei, Oreochromis niloticus, biofloc technology, biomass, fish, nitrogen, phosphorus, rearing, shrimp, sludge, stocking rate
This study aimed to evaluate the effect of different stocking densities of Nile tilapia, Oreochromis niloticus, integrated with Pacific white shrimp, Litopenaeus vannamei, reared in a biofloc system for 57 days. The performance of both species and the ecological efficiency of the system were evaluated. Four levels of tilapia stocking density were evaluated: 0, 8, 16 and 24 fish per tank (90 L useful volume). The initial weight was 4.8 ± 0.1 g and 9.6 ± 0.1 g for shrimp and fish, respectively. The shrimp were fed according to the feed table, and the fish were fed with 1% of fish biomass, stimulating the tilapia to seek food in the biofloc. Results show no difference between average shrimp weight (14.9 ± 0.6 g) and survival (93.0% ± 1.0%). Similarly, fish obtained a final mean weight of 61.9 ± 3.8 g and survival of 91.1 ± 7.9%. Total yield was higher based on the increase in fish density. The sludge produced per animal biomass (sludge:biomass ratio) decreased as fish density increased (y = − 0.0083xx + 0.5995 r2 = 0.87). Nitrogen recovery rose linearly with the increase in fish density (y = 0.036xx + 0.2725, r2 = 0.84), as did phosphorus recovery (y = 0.00711xx + 0.1395, r2 = 0.91). These results demonstrate the feasibility of increasing yield up to 31.2% by integrating L. vannamei and O. niloticus in a biofloc system. Also, the decrease in sludge:biomass ratio and the higher nitrogen and phosphorus recovery increased the sustainability of L. vannamei rearing in a biofloc system.