氨氮胁迫对不同规格刺参(Apostichopus japonicus)存活及非特异性免疫酶活性的影响

本实验以小(6.05±0.44)g/头]、中(14.68±1.76)g/头]、大(25.64±3.27)g/头]的3种不同规格刺参(Apostichopus japonicus)为研究对象,研究了氨氮胁迫浓度为0、2、4、6、8、l0 mg/L时对刺参体腔液中溶菌酶(LSZ)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性的影响.结果显示,在氨氮浓度为8 mg/L时,第10天后,3种不同规格刺参均出现吐肠、化皮,直至死亡.氨氮浓度为10 mg/L时中规格刺参存活率最低,为86.7％.在氨氮浓度为2 mg/L和4 mg/L时,小、中、大规格刺参的3种非特异性免疫酶活性在第4天显著升高,与对照组(氨氮浓度低于0.05 mg/L)差异显著(P＜0.05);第7、10、13天时,LSZ、CAT、SOD酶活性与第4天相比,差异不显著(P＞0.05).在氨氮浓度为6、8、10 mg/L时,LSZ、CAT、SOD酶活性在第7天达到最高,与对照组差异性显著(P＜0.05).氨氮胁迫对3种不同规格刺参的非特异性免疫酶活性的影响存在差异,在同一氨氮浓度胁迫下,敏感性依次为中规格＞大规格＞小规格.研究表明,氨氮胁迫会对刺参存活与免疫产生一定影响,在刺参养殖过程中,水环境中氨氮浓度最好控制在6 mg/L以内.

Effects of Ammonia Nitrogen Stress on the Survival and Activities of Non-Specific Immune Enzymes of Different-Sized Sea Cucumber (Apostichopus japonicus)

In intensive culture system, accumulation of ammonia nitrogen, which is the principal end-product of nitrogenous metabolism, has deleterious effects on aquatic animals. However, there is little information about the effects of ammonia nitrogen on the immunity function of sea cucumber Apostichopus japonicus. This study was conducted to evaluate the effects of ammonia nitrogen stress (concentration gradient: 0, 2, 4, 6, 8, 10 mg/L) on the activities of lysozyme(LSZ), catalase(CAT), superoxide dismutase (SOD) of different-sized sea cucumber with initial body weight of (6.05±0.44) g, (14.68±1.76) g and (25.64±3.27) g. The results were as follow: When the ammonia-N level was 8 mg/L, mortality occurred in three-sized sea cucumber on the 10th day; When the ammonia-N level was 10 mg/L, the medium-sized sea cucumber had the lowest survival rate of 86.7%. When the ammonia-N level was 2 mg/L and 4 mg/L, on the 4th day, three non-specific immune enzymatic activities of three-sized sea cucumber increased, significantly different with the control group (P<0.05). There were no significant differences in enzymatic activities between the 4th, 7th, 10th and 13th day. While the ammonia-N level was 6 mg/L, 8 mg/L, 10 mg/L, three non-specific immune enzymatic activities reached the maximum value on the 7th day, significantly different with the control group (P<0.05). Under the same ammonia nitrogen stress level, the activities of three non-specific immune enzymes of three-sized sea cucumber were different. The sensitivity order of three-sized sea cucumber under ammonia nitrogen stress was: Medium-sized>Big-sized>Small-sized (P>0.05). These results indicated that ammonia nitrogen stress can affect the survival rate and immunity function of sea cucumbers, which will provide the theoretical basis for the mechanism of ammonia stress on sea cucumbers.