中文摘要：

观察二十六碳六烯酸（docosahexaenoi cacid，DHA）对鲤抗氧化能力的影响。设计DHA灌喂（短期）、DHA饲养（长期）和DHA直接处理鲤肝细胞（离体）等3个试验，分别对鲤肝细胞或肝胰脏的总抗（T—AOC）水平、总超氧化物歧化酶（T—SOD）、谷胱甘肽S转移酶（GST）、过氧化氢酶（CAT）活性以及丙二醛（MDA）含量指标进行了测定。结果表明：（1）DHA组鲤肝胰脏T—AOC水平在灌喂后的各时间点上均高于对照组，且在32h时达到显著水平（P〈0．05）。（2）两个油脂水平下，DHA组鲤肝胰脏T-AOC水平、CAT、SOD活性及MDA含量与对照组问差异均不显著（P〉0．05）；血清T-AOC水平、SOD活性DHA组与对照组间差异也不显著（P〉0．05）；12％油脂水平下DHA组GST活性显著低于对照组（P〈0．05），但6％油脂水平下GST活性在两组间差异不显著（P〉0．05）。（3）DHA组鲤肝细胞在处理0．5h、1h时，MDA含量与对照差异不显著（P〉0．05），而在处理后2h、4h、8h，DHA组MDA含量显著高于对照组（P〈0．05），且在4h、8h时达极显著水平（P〈0．01）；DHA组T—SOD活性在处理后4h时显著高于对照组（P〈0．05），而在其它时间点上DHA组与对照组间差异均不显著（P〉0．05）。结果提示，DHA直接或短期作用下，鲤肝胰脏或肝细胞处于氧化应激状态，其抗氧化能力诱导性升高；而DHA长期饲喂后，在正常油脂水平下机体表现出对DHA造成的氧化应激的适应，高油脂水平下DHA的添加则可能通过加剧机体氧化应激状态，造成抗氧化能力的下降。另外，所采用的短期灌喂肝、细胞离体培养以及长期饲养相结合的研究手段可用于外源性物质对鱼类生理活性的评定。

英文摘要：

This experiment was conducted to study the effect of DHA （ docosahexaenoic acid） on anti-oxidation capacity in common carp. Three experiments including DHA oral administration experiment, DHA feeding experiment （long term ） and the incubated hepatocyte treated with DHA experiment （in vitro ） were performed. Anti-oxidation capacity （ T-AOC ）, total superoxide dismutase （ T-SOD ）, glutathione S-transferase （GST） ,catalase（CAT） and maleic dialdehyde（MDA） were determined in the three experiments. The results showed：（ 1 ）T-AOC in DHA group was significantly higher than that in control group at 32 h after DHA administration （P 〈0.05） ,but there was no significant difference between the two groups at 0 h,2 h,4 h,8 h and 16 h （P 〉 0.05）. （2） Under the same dietary lipid level, the MDA content, CAT, SOD activity, T-AOC level of hepatopancreas and serum SOD activity as well as T-AOC level in DHA group were not significantly different from those in the control group;the serum GST activity in DHA group was significantly different from that in control group under 12% dietary lipid level （P 〈 0.05 ）, but no significant between the two groups under 6% lipid level. （3）In vitro experiment, there was no significant difference in MDA content between the DHA group and control group when the hepatocytes were treated with DHA for 0.5 h, 1.0 h, but at 2.0 h, 4.0 h and 8.0 h, the MDA content in the DHA group was significantly higher than that in the control group （from P 〈0.05 to P 〈0.01 ）;the T-SOD activity was significantly higher in the DHA group than that in the control group when the hepatocytes were treated for 4h. But at other times, there was no significant difference between the two groups （ P 〉 0. 05 ）. These results suggest that treated with DHA for a short time, the hepatopancreas or hepatocyte of common carp are under oxidative stress and the anti-oxidation capacity is induced. On the other hand, the body was acclimatized to the oxidative stress c