在循环水养殖系统中养殖密度对红鳍东方鲀应激反应和抗氧化状态的影响

Effects of the stocking density on stress response and antioxidant status of Takifugu rubripes in recirculating aquaculture systems

养殖密度是影响养殖水体水质和鱼类生长性能的重要因素。通过红鳍东方鲀(Takifugu rubripes)循环水养殖试验和硝酸盐氮急性处理试验,分别研究不同养殖密度(12.5~20.0 kg/m^3)和不同硝酸盐氮质量浓度(1.0、25.0、100.0和150.0 mg/L)对养殖水体水质、红鳍东方鲀生长性能、应激反应和抗氧化状态的影响。结果显示:不同养殖密度对红鳍东方鲀养殖水体的pH、氨氮和亚硝酸盐氮质量浓度无显著性影响,但较高密度会导致硝酸盐氮质量浓度显著升高,最高升至24.5 mg/L。在较高养殖密度条件下,红鳍东方鲀的生长性能(终体质量、特定增长率和饲料转化率)和抗氧化能力(总抗氧化能力、超氧化物歧化酶、谷胱甘肽过氧化物酶)较弱,但其脂质过氧化(丙二醛)和应激反应(葡萄糖、乳酸和皮质醇)较强。此外,在硝酸盐氮急性处理试验中,红鳍东方鲀未出现死亡。当硝酸盐氮质量浓度为100.0和150.0 mg/L时,红鳍东方鲀抗氧化能力较弱,而应激反应较强。综上,当养殖密度为16.5 kg/m^3时,红鳍东方鲀的生长和抗氧化状态较好,且应激压力较小,这表明在较高密度条件下,养殖水体硝酸盐氮质量浓度的升高不是引起鱼类生长抑制的主要原因。

Stocking density is an important factor affecting aquaculture water quality and fish growth performance.Recirculating aquaculture test and nitrate nitrogen acute treatment test of Takifugu rubripes were conducted to investigate the effects of stocking density(12.5-20.0 kg/m^3) and nitrate nitrogen mass concentration(1.0,25.0,100.0 and 150.0 mg/L) on aquaculture water quality,growth performance,stress response and antioxidant status of Takifugu rubripes.The results indicated that the stocking density had no significant effect on pH,ammonia nitrogen and nitrite nitrogen mass concentration in the aquaculture water of Takifugu rubripes,but higher density would lead to significant increase in nitrate nitrogen mass concentration,with the maximum value being 24.5 mg/L.Higher stocking density resulted in lower growth performance(final weight,specific growth rate and bait conversion rate) and antioxidant capacity(total antioxidant capacity,superoxide dismutase and glutathione peroxidase) and higher lipid peroxidation(MDA) and stress response(glucose,lactic acid and cortisol).In addition,in nitrate nitrogen acute treatment test,no Takifugu rubripes died.When the nitrate nitrogen mass concentration was 100.0 and 150 mg/L,the antioxidant capacity of Takifugu rubripes was lower while the stress response was higher.In conclusion,when the stock density was 16.5 kg/m^3,the growth and antioxidant status of Takifugu rubripes were good and the stress response was lower,which indicated that under higher density,the increase of nitrate nitrogen mass concentration in aquaculture water was not the main reason for fish growth inhibition.