亚硝酸盐胁迫对尖吻鲈稚鱼抗氧化酶活性及皮质醇的影响

Effect of acute nitrite on antioxidant enzymes and cortisol in juvenile Lates calcarifer

作者采用半静水生物测试法,对尖吻鲈稚鱼(Latescalcarifer)(15日龄)进行急性亚硝酸盐胁迫试验,试验共设定4个亚硝酸盐浓度梯度试验(0、100、300和500 mg/L),并分别于0、6、12、24、36、48和72h处进行取样,测定其超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、酸性磷酸酶(ACP)以及谷胱甘肽过氧化物酶(GSH-PX)等抗氧化酶活性及皮质醇含量,旨在揭示尖吻鲈稚鱼在急性亚硝酸应激下,抗氧化酶及激素的调节机制。分析结果表明试验剂量和时间均对各抗氧化酶活性和皮质醇含量影响显著(P<0.05)。实验结束时,SOD活性显著高于对照组,而POD活性均显著低于对照组, CAT活性除最低浓度胁迫处理组显著低于对照组以外,其他均显著高于对照组, ACP活性低于或略低于对照组水平, GSH-PX活性最低值出现在最高浓度胁迫组且显著低于对照组,而皮质醇浓度均显著低于对照组(P<0.05)。结果证明了鱼体抗氧化酶活性和皮质醇对亚硝酸盐刺激具有调节反应,一定程度上也证明了尖吻鲈仔、稚鱼较强的亚硝酸盐耐受能力。

This study aimed to investigate the effects of acute nitrite toxicity(0,100,300,and 500 mg/L)in juvenile Lates calcarifer(15 DPH)using the semi-static bioassay method.Samples were obtained at 0,6,12,24,36,48,and 72 h,to measure and analyze the activity of antioxidant enzymes and concentration of cortisol to elucidate the regulatory mechanism.The findings revealed that both the concentration and exposure time of nitrite markedly affected the aforementioned parameters.By the end of the experiment,the SOD activity of samples in the experimental group was significantly higher than that of samples in the control group,whereas POD was significantly lower than the control group.CAT was significantly higher than the control group,except the minimum-concentration treatment group;ACP was lower or slightly lower than the control group.In addition,the minimum value of GSH-PX activity was observed in the highest-concentration treatment group and was significantly lower than the control group,and the cortisol concentration was substantially lower than the control group.This study demonstrates that L.calcarifer exhibits a regulatory response on antioxidant enzyme activity and cortisol concentration following nitrite stimulation.Furthermore,it proves to a certain extent the strong tolerance of juvenile L.calcarifer to nitrite.