美人鱼发光杆菌对凡纳滨对虾非特异性免疫功能及抗病力的影响

Effect of Photobacterium damselae on the non-specific immune response and disease resistance of Litopenaeus vannamei

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。

Litopenaeus vannamei at （4.83 ± 0.36）g body weight were fed with 0.1% heat-killed, 1% heat-killed and 0. 1% living Photobacterium damselae for 21 days respectively. The serum was collected at 0, 5, 10, 15 and 20 days post-immunization and Phenoloxidase （PO）, acid phosphatase （ACP）, alkaline phosphatase （AKP）, superoxide dismutase （SOD） and lysozyme activity （UL） in the serum of L. vannarnei were determined to evaluate the nonspecific immune effect of P. damselae After 21 days, the shrimps were challenged by white spot syndrome virus （WSSV） and the mortalities of challenging test were recorded. The results showed that most PO, ACP, AKP, UL and SOD in the serum of L. vannamei of the test groups were signifi- cantly different （P〈0. 05 or P〈0. 01）, and the resistance ability of shrimps to WSSV was also sig- nificantly enhanced by the diet supplemented with P. darnselae The group fed with 10g heat-killed P. damselae per 1 kg shrimps exhibited the strongest resistance to WSSV in 14 days and its final cumulative mortality was 63.3 %＋5.8 %, while the control was 96.7%＋7. 3 %. The results indicated that P. damselae improved shrimp non-specific immunity and its resistance to WSSV, suggesting that it might be a promising diet supplement in shrimp farming.