投喂负荷对循环水养殖大西洋鲑生长及氮、磷收支的影响

Effects of feeding load on growth,nitrogen and phosphorus budgets of Atlantic salmon( Salmo salar) in recirculating aquaculture systems

为研究封闭循环水高密度养殖[(28.30±0.51)kg/m3]下投喂负荷对循环水养殖大西洋鲑(Salmo salar)生长及氮、磷收支的影响,设置4个投喂负荷:1.2 g/L(A组)、1.8 g/L(B组)、2.4 g/L(C组)、3.0 g/L(D组),挑选体重为(377.5±14.5)g的大西洋鲑进行70 d养殖试验。结果显示,投喂负荷对大西洋鲑生长、系统水质和氮、磷收支均有显著影响(P<0.05)。C组特定生长率(1.05%/d)显著高于A组(77.97%)和B组(56.72%)(P<0.05),饲料系数(0.90)显著低于A组(18.18%)和B组(10.89%)(P<0.05)。C组的总氨氮、磷酸盐和总氮浓度均显著高于A组(P<0.05)。C组的氮沉积率(48.21%)和系统磷输出(73.93%)显著高于A组(52.66%和19.07%)(P<0.05),氮输出(36.07%)显著低于A组(14.85%)(P<0.05)。研究表明,适宜的投喂负荷不仅能促进大西洋鲑生长和对氮、磷等营养素的利用,而且会减少系统氮、磷等污染物的输出,降低系统对环境的影响。

Effects of feed loading on growth and nitrogen and phosphorus budgets of Atlantic salmon （ Salmo salar） were studied in a 70-day experiment in recirculating aquaculture systems. Atlantic salmon with average weight of （377.5 ±14.5） g were fed by four feeding loads （ 1.2 g/L for group A, 1.8 g/L for group B, 2.4 g/L for group C, 3.0 g/L for group D ）. The results indicated that feeding loads had significant effects on salmon growth, water quality and nutrient budgets of recirculating aquaculture system （ P 〈 0.05 ）. The specific growth rate of group C （1.05%/d） was significantly higher than group A and B by 77.97% and 56. 72% （P 〈 0. 05 ） respectively, while feed conversion rate （ 0.90 ） was significantly lower than that in the group A and B by 18.18% and 10.89% （P 〈0.05）. Concentrations of total ammonia, phosphate and total nitrogen in group C were significantly higher than that in group A （ P 〈 0.05 ）. The nitrogen deposition rate （48.21%） and phosphorus output （73.93%） for system of group C were higher than that in group A by 52. 66% and 19.07% （P 〈0.05）, whilst nitrogen output （36.07%） was lower by 14.85% （P 〈0.05）. The study showed that suitable feeding load can improve growth and nutrients utilization for salmon. It can also reduce environmental impacts of system by reducing output of wastes including nitrogen, phosphorus, etc.