Acta Scientiarum: Animal Sciences (Jul 2008)
Performance e retenção de metais pesados em três linhagens de juvenis de tilápia-do-Nilo em hapas = Performance and retention of heavy metals in fingerlings of Nile tilapia in hapas
Abstract
O trabalho objetivou avaliar o desempenho produtivo de três linhagens de tilápia-do-Nilo (Oreochromis niloticus), GIFT, Bouaké e Chitralada, durante a produção de juvenis no período de fevereiro a maio de 2007. Os alevinos sexualmente revertidos foram alojados em 12 hapas com 9 m3, instaladas em um tanque escavado com 0,7 ha de lâmina de água. Ao final de 93 dias de cultivo, verificou-se que houve diferença significativa para a sobrevivência entre as três linhagens (p This assay aimed to evaluate the productive performance of three Niletilapia (Oreochromis niloticus) strains – GIFT (Genetic Improvement of Farmed Tilapia), Bouake and Chitralada – during the production of juveniles from February to May, 2007. The sexually reverted fingerlings were stored in twelve 9 m3 hapa nets installed in a pondwith 0.7 ha water blade. At the end of 93 days of culture, a significant change in survival among the three strains (p < 0.05) was verified, where GIFT (96.80%) surpassed Chitralada (90.85%) and Bouake (77.74%). The average final weight (40.49, 34.53 and 32.42 g), daily body mass gain (0.43, 0.37 and 0.34 g day-1) feed conversion (1.80; 1.81 and 1.81) and final biomass (19,594.79, 19,528.85 and 16,488.99 g), did not present significant differences among GIFT, Bouake and Chitralada, respectively. The average of fish over 25 g was over 80% of the lots, which guaranteed uniformity and standardization of the juveniles. The toxic metals cadmium and lead were above the tolerable level in the fish; however, the metal chromium was not detected. The GIFT strain presented the best performance only for the survival rate in this culture system, although it contained high indices of heavy metals in comparison with the other two strains.
