氨氮对中华小长臂虾的急性毒性及非特异性免疫指标的影响

采用生物毒性实验方法研究了氨氮对中华小长臂虾的急性毒性作用, 结果表明: 在温度为(18±1)℃, pH为7.3±0.1条件下, 氨氮对中华小长臂虾24h、48h、72h、96h 的半致死浓度(LC₅₀)分别为565.47、371.16、291.16和272.50 mg/L, 安全浓度为 27.25 mg/L。转化为非离子氨的LC₅₀分别为3.74、2.45、1.93 和1.80 mg/L, 安全浓度为0.18 mg/L。根据96h 的LC₅₀和安全浓度按照等差数列设置5个氨氮浓度梯度, 分别60、100、140、180和220 mg/L, 研究氨氮胁迫对中华小长臂虾非特异性免疫指标的影响。结果显示: 在24h时, 除了220 mg/L的肌肉组织, 中华小长臂虾肝胰腺和肌肉中的超氧化物歧化酶(SOD)活性显著性高于对照组, 并具有明显的剂量效应, 在48—96h均回落到正常水平; 在24h时, 中华小长臂虾氨氮处理组中肝胰腺的酸性磷酸酶(ACP)与对照组未发生显著变化, 而碱性磷酸酶(AKP)则显著高于对照组, 在48—96h两者的140、180和220 mg/L处理组均显著低于对照组; 除了140 mg/L 处理组的ACP活性外, 肌肉中的ACP和AKP活性从24h开始就出现了显著性下降, 始终低于对照组。研究获得了氨氮对中华小长臂虾的急性毒性结果和在高氨氮胁迫下非特异性免疫指标的变化规律, 发现中华小长臂虾对氨氮具有较强的耐受性, 但高浓度的氨氮会对中华小长臂虾的免疫酶活性产生抑制作用, 研究结果可为中华小长臂虾健康养殖发展提供科学依据。

EFFECT OF AMMONIA NITROGEN ON ACUTE TOXICITY AND NON-SPECIFIC IMMUNE PARAMETERS OFPALAEMONETES SINENSIS

The current study explored the acute biological toxicity of ammonia-N onPalaemonetes sinensis. In the con-dition of (18±1)℃, pH 7.3±0.1, the half lethal concentrations of ammonia-N were 565.47 mg/L for 24h, 371.16 mg/L for 48h, 291.16 mg/L for 72h, and 272.50 mg/L for 96h, respectively, and the safe concentration was 27.25 mg/L. In the same condition, half lethal concentrations of non-ionic ammonia were 3.74 mg/L for 24h, 2.45 mg/L for 48h, 1.93 mg/L for 72h, 1.80 mg/L for 96h respectively and the safe concentration was 0.18 mg/L. Five different concentrations (60 mg/L, 100 mg/L, 140 mg/L, 180 mg/L and 220 mg/L) were used to study the influence of ammonia nitrogen stress on the non-specific immune indexes based on 96hLC50 and safety concentration. Results showed that the superoxide dismutase (SOD) in hepatopancreas and muscle of P. sinensis significantly increased by ammonia nitrogen at 24h ex-cept muscle tissue in 220 mg/L, which decreased to the normal level at 48—96h. Compared with the control group, acid phosphatase (ACP) in hepatopancreas of P. sinensis by ammonia nitrogen treatment was not changed significantly at 24h, while alkaline phosphatase (AKP) was significantly increased. At 48—96h, both ACP and AKP were lower than the control group. Muscle ACP and AKP by ammonia nitrogen treatments except 140 mg/L were significantly lower than those in the control group at 24 and 96h. This study revealed thatP. sinensis had strong tolerance to ammonia ni-trogen. High ammonia nitrogen had can inhibit the activities of immune enzyme. The results will provide the scientific basis for the aquaculture of P. sinensis.