高温与氨氮复合胁迫对凡纳滨对虾渗透调节的影响

Combined Effects of High Temperature and Ammonia Stress on Osmoregulation of Pacific White Shrimp Litopenaeus vannamei

将体质量(6.77±0.51)g凡纳滨对虾饲养在200 L玻璃纤维桶中,每桶50尾,设置2个温度(恒温30℃和1 h内由30℃急升至33℃),每个温度设置以氯化铵溶液调节的4个氨氮质量浓度(0、5、15、25 mg/L),共8个试验组,每组3个平行。胁迫72 h时测定鳃中Na^(+)/K^(+)-ATP酶与Ca^(2+)-ATP酶活性以及肌肉和鳃中游离氨基酸含量,分析高温与氨氮复合胁迫对凡纳滨对虾渗透压生理调节的影响。试验结果显示:(1)同一温度下,30℃时,25 mg/L氨氮组的Na+/K+-ATP酶活性和5 mg/L氨氮组的Ca^(2+)-ATP酶活性均显著升高,而33℃时,3个氨氮胁迫组Na^(+)/K^(+)-ATP酶和Ca^(2+)-ATP酶活性均显著升高(P<0.05);(2)同一氨氮质量浓度下,30℃和33℃试验组的Na^(+)/K^(+)-ATP酶和Ca^(2+)-ATP酶活性均差异显著,且25 mg/L氨氮质量浓度下33℃试验组酶活性显著低于30℃试验组(P<0.05);(3)氨氮质量浓度为15 mg/L和25 mg/L时,33℃试验组鳃和肌肉游离氨基酸总含量均显著高于30℃组(P<0.05);(4)30℃和33℃试验组与氨氮胁迫下,肌肉中丙氨酸含量均随氨氮质量浓度升高而显著增加,且33℃试验组显著高于30℃组(P<0.05)。试验结果表明,高温与氨氮复合胁迫对凡纳滨对虾Na^(+)/K^(+)-ATP酶和Ca^(2+)-ATP酶活性以及游离氨基酸含量影响显著,会造成凡纳滨对虾渗透压生理调节功能紊乱。

The changes in Na^(+)/K^(+)-ATPase and Ca^(2+)-ATPase activities in gill and the contents of free amino acid(FAA)in muscle and gill were monitored in Pacific white shrimp Litopenaeus vannamei with body weight of(6.77±0.51)g reared in 200 L fiberglass barrels at initial stocking density of 50 per barrel under two temperatures(normally 30℃and acute increase from 30℃to 33℃within 1 h)×4 ammonia nitrogen concentrations(0,5,15,and 25 mg/L)adjusted with ammonium chloride solution for 72 h to evaluate the effects of ammonia-nitrogen stress on the physiological osmoregulation of Pacific white shrimp under acute warming temperature.The results showed that the activities of Na^(+)/K^(+)-ATPase and Ca^(2+)-ATPase were found to be significantly increased in 25 mg/L and 5 mg/L ammonia groups at 30℃(P<0.05),significant increase in activities of Na^(+)/K^(+)-ATPaes and Ca^(2+)-ATPase in all ammonia groups at 33℃(P<0.05).In the same ammonia concentration,there were significant differences in the activities of Na^(+)/K^(+)-ATPase and Ca2+-ATPase between 30℃and 33℃groups,significantly lower enzyme activity in the 33℃group than that in the 30℃group at 25 mg/L ammonia concentration(P<0.05).In gill and muscle,the total contents of FAA were significantly lower in the 33℃group than that in 30℃group at ammonia concentration of 15 mg/L and 25 mg/L(P<0.05).Under ammonia stress,alanine level in muscle was increased significantly in 30℃and 33℃groups with increasing ammonia concentration(P<0.05),and significantly higher at 33℃than at 30℃group(P<0.05).The findings indicated that ammonia stress sharply affected Na^(+)/K^(+)-ATPase and Ca^(2+)-ATPase activities as well as the contents of FAA under acute warming temperature,leading to dysfunction of the physiological osmoregulation of Pacific white shrimp.