对照组提高了26.20%、18.68%和17.08%;而CAT和T-SOD活性则均显现先激活后抑制的趋势，高浓度、长时间氨氮胁迫对幼鱼肝脏抗氧化酶活性影响较大，导致机体抗氧化能力的减弱。研究结果表明，异育银鲫‘中科3号’对氨氮的耐受性高于青鱼、草鱼、鲢鱼和鲤鱼等其他常见大宗鱼类，但是氨氮急性胁迫破坏了幼鱼肝脏抗氧化系统，长期处于氨氮胁迫下将不利于幼鱼健康生长。
关键词：异育银鲫鱼‘中科3号’;氨氮;急性毒性;肝脏;抗氧化酶
中图分类号：S917.4 文献标志码：A 论文编号：cjasl8070019
Ammonia Nitrogen： Effects on Acute Toxicity and Antioxidant Enzymes System in
Liver of Juvenile of Allogynogenetic gibel carp ‘CAS Ⅲ’
Xue Lingzhan1， Wu Suqiong2， Zhang Kun3， Fan Haiping1， Chen Bin1， Tian Tian1， Lin Xuan2
（1Freshwater Fisheries Research Institute of Fujian Province， Fuzhou 350002， Fujian， China; 2College of Animal Science， Fujian Agriculture and Forestry University， Fuzhou 350002， Fujian， China; 3Fujian Tianma Science and Technology Group Co.， Ltd， Fuzhou 350308， Fujian， China）
Abstract： The study aims at the toxicological effect of ammonia nitrogen on Allogeneic crucian carp ‘CAS Ⅲ’. The aquatic organism toxicity method was used under hydrostatic condition indoor. The acute toxicity test of ammonia nitrogen on juvenile of Allogynogenetic gibel carp ‘CAS Ⅲ’ was conducted， and the changes of catalase （CAT）， total superoxide dismutase （T-SOD） and malondialdehyde （MDA） in liver tissues were tested. The results showed that after ammonia nitrogen stress， the median lethal concentration （LC50） of total ammonia nitrogen was 276.51mg/L at 24h， 190.62mg/L at 48h and 148.62mg/L at 96h， and the LC50 of un-ionized ammonia was 2.52mg/L at 24h， 1.74 mg/L at 48 h， and 1.36 mg/L at 96 h. The safe concentration of total ammonia nitrogen and un-ionized ammonia was 14.87 mg/L and 0.14 mg/L， respectively， for juvenile. Under ammonia nitrogen stress， the content of MDA in the liver increased by 26.20%， 18.68% and 17.08% compare with the control （P<0.05）， but CAT and T- SOD appeared to be activated at first and then inhibited， and antioxidase was induced more significantly at relatively higher concentration of ammonia nitrogen and long time exposure， and it weakened the antioxidant capacity of the body. The results reveal that ammonia tolerance of Allogynogenetic gibel carp ‘CAS Ⅲ’ is higher than that of Mylopharyngodon piceus， Ctenopharyngodon idellus， Hypophthalmichthys molitrix （Valenciennes， 1844）， Cyprinus carpio Linnaeus， and other conventional freshwater fish. However， acute ammonia nitrogen stress damaged the liver antioxidant system and it is harmful to the health and growth of juvenile fish.
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