福瑞鲤对氨氮胁迫的生理响应

以福瑞鲤(Cyprinus carpio)为材料,研究不同浓度氨氮(0、10、20和30 mg/L)处理对幼鱼鳃组织中抗氧化系统和Na~+/K~+-ATP酶活力的影响。结果显示,氨氮胁迫6 h诱导H_2O_2含量、总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性迅速显著升高,并在胁迫24 h时达到最高水平。胁迫96 h后,各处理组H2O2含量、SOD活性和总抗氧化能力均低于对照组水平,MDA含量显著增加。氨氮胁迫后,Na~+/K~+-ATP酶基因转录水平和蛋白活性呈先降低后升高又降低的变化趋势,参与胁迫过程中渗透压的调控。研究结果表明,低浓度氨氮胁迫后,福瑞鲤鳃组织通过调节细胞抗氧化能力,提高Na~+/K~+-ATP酶活性,有效改善鱼体的抗氨氮胁迫能力,但是高浓度氨氮胁迫对鳃组织造成氧化损伤。

Physiological response of FFRC strain common carp to ammonia stress

The effects of ammonia-N on antioxidant system and Na+ /K+-ATPase were studied in the gill of FFRC strain common carp ( Cyprinus carpio L. ) . The carp were transferred off the freshwater and exposed to different ammonia-N levels (0, 10, 20 and 30 mg/L), and each ammonia-N level was randomly triplicate and sampled at 0, 6, 24, 48 and 96 h, respectively. The results showed that with the concentration of ammonia-N increased, the H2 O2 content, total antioxidant capacity ( T-AOC) and superoxide dismutase ( SOD) activity enhanced significantly at first 6 h and reached the maximun after 24 h exposure. Then, the H2 O2 content, SOD activity and T-AOC decreased, and MDA content increased signifi-cantly in all ammonia-N treatment group after 96 h exposure. The gene expression level of Na+ /K+-ATPaseα1 and Na+ /K+-ATPase β1 increased at 24 h, and then decreased to be lower than that of control group after 96 h exposure. Mean-while, Na+ /K+-ATPase activities decreased at first 6 h, and then increased gradually and reached the maximum at 48 h, showing the induction of Na+ /K+-ATPase in response to ammonia-N stress. These results indicated that ammonia-N stress induced changes in antioxidant system and Na+ /K+-ATPase level, which play a key role in preventing ammonia-N damage in gill cells.