转vp28蓝藻口服剂对凡纳滨对虾抗白斑综合征病毒能力及免疫反应的影响

为探讨转vp28蓝藻(Anabaena sp.PCC7120)口服剂对凡纳滨对虾抗白斑综合征病毒能力及其相应的免疫反应,本研究将此口服剂免疫幼虾7 d,再分别通过投喂攻毒和浸泡攻毒,测定其存活率及相应的免疫指标。投喂攻毒和浸泡攻毒的实验组存活率分别为78.8%和83.19%,表明该口服剂能显著增强对虾抗白斑综合征病毒的能力。蓝藻口服剂免疫对虾的酶活性检测结果显示,超氧化物歧化酶(SOD)、酚氧化酶(PO)、过氧化氢酶(CAT)和碱性磷酸酶(AKP)活性在免疫后2 h均有上升趋势,且在48或96 h达到最高值,这表明该口服剂能引起对虾体内酶活性变化。投喂攻毒的对虾酶活性检测结果显示,实验组攻毒后的对虾肝胰腺SOD活性分别比阳性对照组、野生型组、空载体组显著提高42.10%、32.26%和16.04%,且攻毒后的肌肉SOD活性分别比阴性对照组、阳性对照组、野生型组和空载体组略微提高17.70%、11.50%、15.00%以及10.00%。实验组攻毒后的对虾肝胰腺PO、CAT和AKP活性比阳性对照组分别提高12.17%、88.80%和240.07%,比野生型组分别提高21.49%、30.90%和100%;酸性磷酸酶(ACP)活性比阴性对照组略微提高,而在肌肉中各组ACP活性无显著性差异。同时浸泡攻毒组结果与投喂攻毒组具有类似的趋势。浸泡攻毒的实验组CAT和AKP活性显著高于其余处理组,且CAT活性比投喂攻毒更为显著。浸泡攻毒的实验组肝胰腺PO活性显著高于阳性对照组、野生型组和空载体组,而各组肌肉ACP活性无显著性差异。研究表明,转vp28蓝藻口服剂能够增强凡纳滨对虾抗病能力并延缓对虾死亡。转vp28蓝藻PCC7120本身可作为幼虾饵料直接投喂,无需提取纯化,有望大规模应用于对虾养殖产业。

Effect of Anabaena-expressed VP28 against white spot syndrome virus and related immune response in Litopenaeus vannamei

This paper described a kind of subunit vaccine, and the effect of Anabaena-expressed VP28 against white spot syndrome virus (WSSV) and the related immune response in Litopenaeus vannamei. Firstly, L. vannamei was orally administered by feeding Anabaena-expressed VP28 for 7 days. Secondly, the shrimp was challenged with WSSV and its mortality was monitored. Finally, the shrimp related immune index was measured. The results revealed that Anabaena-expressed vp28 can significantly improve the shrimp''s ability against WSSV. The survival rate of feeding and immersing infected WSSV is 78.80% and 83.19% respectively. The results showed that oral agent can enhance the ability against WSSV in L. vannamei. After shrimp was administrated by Anabaena-expressed vp28, the shrimp enzyme acitivity at different time points showed that superoxide dismutase (SOD), phenoloxidase (PO), catalase (CAT), alkaline phosphatase (AKP) at 2 h after immunization were rising, and reached peak at 48 h or 96 h, which suggested that oral agent could cause the change of enzyme activity. The enzyme activity of shrimp hepatopancreas and muscle after feeding infection showed that the SOD activity of experimental group in hepatopancreas after challenge was 42.10%, 32.26% and 16.04% higher than those of the positive group, wide type group and blank group. In muscle, SOD activity was 17.70%, 11.50%, 15.00% and 10.00% higher than those of negative control, positive control, wide type and blank group after challenge. And the PO activity, CAT activity, and AKP activity of the experimental group were 12.17%, 88.80% and 240.07% higher than that of the positive control after challenge in hepatopancreas respectively. The PO activity, CAT activity, and AKP activity of the experimental group were 21.49%, 30.90% and 100% higher than that of wide type after challenge in hepatopancreas respectively. ACP activity was slightly higher than that of negative control, but ACP activity had no significant difference in the muscle groups. The results of shrimp PO, CAT, AKP and ACP activity of immersing infection were similar to feeding infection. The experiment group CAT and AKP activity after immersing infection is significantly higher than other groups, and the CAT activity of immersing infection were more significant than feeding infection. The PO activity of shrimp hepatopancreas of experiment group after immersing infection was significantly higher than those of positive control, wide type and blank, but ACP activity of different group was not significantly different. This paper showed that Anabaena-expressed vp28 can strengthen shrimp''s resistance to WSSV and decrease the mortality of L. vannamei from white spot disease. The Anabaena-expressed vp28 can be drug and feed from the same feedstock without purification, which has great application potential for field use in large-scale production.