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Shrimps( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight(11.10 vs 10.50 g), body length(107.23 vs 106.42 mm), survival rate(67.80% vs 66.40%), and yield(6.42 vs 5.99 kg/m 3), and lower feed conversion ratio(1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable(10 4 –10 6 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component(75.7% of total input), shrimp feed(21.0%), water(2.06%), and shrimp biomass(1.22%). The major outputs of Cu occurred via the mechanical filter(41.7%), water renewal(15.6%), and draining of the sediment trap(15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems(30.70 mg/kg wet weight) was significantly higher than that in control systems(22.02 mg/kg). Both were below the maximum permissible concentration(50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.
Shrimps (Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate the effects of 0.3 mg / L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had a greater final weight (11.10 vs The survival rate (67.80% vs 66.40%), and yield (6.42 vs 5.99 kg / m3), and lower feed conversion ratio (1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable (10 4 -10 6 colony forming units / mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate- oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg / L while in the control systems it increased from 0.006 2 to 0.018 mg / L. The main sources of Cu in the treated syste The major outputs of Cu occurred via the mechanical filter (41.7%), shrimp feed (21.0%), water (2.06%), and shrimp biomass The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu- treated systems (30.70 mg / kg wet weight) were significantly higher than that in control systems (22.02 mg / kg). Both were below the maximum permissible concentration (50 mg / kg) recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg / L Cu. The mechanical filter is the main route for Cu removal.