氨氮胁迫对刺参几种免疫酶活性的影响

Effect of exposure to ammonia nitrogen stress on immune enzyme of holothurian Apostichopus japonicus

以养殖刺参(Apostichopus japonicus)为研究对象,对不同浓度的氨氮处理及病菌感染条件下刺参体腔液免疫酶的变化进行了测定。结果表明:随着氨氮处理强度的增加,刺参体腔液中超氧化物歧化酶(SOD)、碱性磷酸酶(ALP)、谷胱甘肽过氧化物酶(GPX)及溶菌酶(LSZ)活性呈现先升高后降低的趋势,而同时感染病菌的情况下,较低质量浓度的氨氮胁迫可使SOD、GPX、ALP及LSZ活性上升,但在较高浓度氨氮处理时,酶活性的诱导则受到抑制。说明适宜浓度的氨氮处理可增强刺参的免疫力,从而减轻病菌感染对刺参造成的免疫功能损伤和提高刺参抗病力。刺参在感染病原菌假交替单胞菌(Pseudoalte-romonas sp)的条件下,3 mg/L、4 mg/L和6 mg/L浓度的氨氮处理第6天,刺参的累积发病死亡率分别为44.4%、55.6%和72.2%,高于对照组,表明较高浓度的氨氮胁迫能够显著降低刺参的免疫力,增加对病原菌的易感性。因此,在刺参养殖过程中,氨氮浓度的调控具有重要的意义。

The change of immune enzyme in the coelomic fluid of holothurian Apostichopusjaponicus under ammonia treatment and pathogen-infected condition was investigated. The results indicated that with the increase of ammonia-N concentration, the activities of superoxide dismutase （SOD）, glutathione peroxidase （GPx）, alkaline phosphatase （ALP） and lysozyme （LYZ） were first increased and then decreased. In the presence of bacteria infection, lower concentrations of ammonia nitrogen could increase the activities of SOD, GPX, ALP and LSZ, but higher concentrations of ammonia nitrogen treatment inhibited the enzyme activities. This suggested that moderate aquatic ammonia nitrogen stresses may enhance the immunity of sea cucumber, reduce the immune damage caused by bacteria infection, and promote the disease resistance ability of sea cucumber. The cumulative mortality of sea cucumber were 44.4%, 55.6% and 72.2% in the presence of pathogen （Pseudoalteromonas sp.） infection and 3, 4 and 6 mg/L ammonia nitrogen treatment, which were higher than that of control group, suggesting that higher concentrations of ammonia nitrogen stress can significantly reduce the immunity of the sea cucumber, increase susceptibility to pathogens. Therefore, regulation and control of ammonia nitrogen concentration are very important during sea cucumber cultivation.