亚硝态氮胁迫对斑节对虾(非洲群体)氧化应激、能量代谢和渗透调节的影响

Effects of acute nitrite stress on oxidative stress,energy metabolism and osmotic regulation of Penaeus monodon

为研究亚硝态氮(NO2-N)对斑节对虾(非洲群体)氧化应激、能量代谢和渗透平衡的影响,实验选取体长(3.0±0.5)cm的斑节对虾,设置0(对照组)、5、10和15 mg/L(3个胁迫组)的亚硝态氮浓度梯度,进行了为期72 h的急性胁迫。实验结果显示,肝胰腺氧化应激因子活性(或含量)随着胁迫时间发展而变化。超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)以及一氧化氮合酶(NOS)活性先升高后下降,24 h,SOD和GSH-Px、NOS活性达到最大值,10 mg/L胁迫组的SOD、GSH-Px活性和15 mg/L胁迫组的NOS活性显著高于其他3组;丙二醛(MDA)含量变化相反,24 h胁迫组的MDA含量最小,其中10 mg/L胁迫组显著低于其他3组;48 h,CAT活性达到最大值,10 mg/L胁迫组显著高于其他3组;一氧化氮(NO)含量随着胁迫时间的延长而逐渐升高,72 h,NO含量最高,15 mg/L胁迫组显著高于其他3组。血清能量代谢指标中脂肪酶(LPS)活性先上升后下降,48 h,LPS活性达到最大值,其中10 mg/L胁迫组显著高于其他3组;而己糖激酶(HK)、磷酸果糖激酶(PFK)、丙酮酸激酶(PK)活性和甘油三酯(TG)含量明显下降,72 h,HK、PFK、PK活性和TG含量达到最小值,15 mg/L胁迫组显著低于其他3组。鳃丝中渗透调节参数——Na^(+)、K^(+)-ATP酶(Na^(+)、K^(+)-ATPase)活性在胁迫过程中始终下降,经过72 h的亚硝态氮胁迫,Na^(+)、K^(+)-ATPase活性达到最小值,15 mg/L胁迫组显著低于其他3组。研究表明,斑节对虾可通过提高抗氧化能力,增强对脂质吸收和利用,调节原有渗透平衡来应对亚硝态氮胁迫,这种作用的发挥具有一定的时间和浓度限制。本实验将为进一步探索亚硝态氮胁迫的分子机制提供数据支持。

Penaeus monodon(African group)accommodates industrial aquaculture and has promising market prospects.But the deterioration of water quality causes frequent occurrence of diseases.Nitrite is a common pollutant,and the experiment was conducted to observe its effect on oxidative stress,energy metabolism and osmotic regulation.Four gradients of nitrite concentrations(0.1,5,10 and 15 mg/L)were set for 4 groups,and three parallels were set for each group.After the acute stress experiment for 72 hours,enzyme activities or substance content were assayed.①As for oxidative stress factors in gill,activities of SOD,GSH-Px,CAT and NOS increased initially and decreased subsequently.At 24 h,the activities of SOD,GSH-Px and NOS reached maximum.The activities of SOD and GSH-Px in the 10 mg/L group and NOS activity in 15 mg/L group were significantly higher than other groups.On the contrary,MDA content in stress groups was the lowest at 24 h,and the 10 mg/L group was significantly lower than other groups.At 48 h,CAT activity reached the maximum,and the CAT activity of 10 mg/L group was significantly higher than other groups.At 72 h,the NO content reached maximum,and 15 mg/L group was significantly higher than other groups.②The indicator of serum energy metabolism,LPS,increased at first and decreased then.The activities of HK,PFK,PK or TG content,decreased obviously during stress process.At 48 h,LPS activity reached maximum,and 10 mg/L group was significantly higher than other groups.At 72 h,the activities of HK,PFK,PK and TG content reached minimum,15 mg/L group were significantly lower than those of other groups.③The gill osmotic regulation parameters,Na^(+),K^(+)-ATPase,decreased during whole process.At 72 h,the Na^(+),K^(+)-ATPase activity reached the minimum,and the 15 mg/L stress group was significantly lower than other groups.Results showed that P.monodon could improve antioxidant capacity,enhance lipid absorption and utilization,and disturb osmotic balance when exposed to acute nitrite stress.But only within certain concentration or time limits can it come into play.The result will provide data support for the further exploration of molecular mechanisms and also provide theory support for healthy prawn farming.