WSSV人工感染量和饵料对中国明对虾存活时间的影响

摘要

为揭示不同白斑综合征病毒(white spot syndrome virus,WSSV)病毒量对于中国明对虾存活时间和存活率的影响,实验设计了逐尾、定量人工感染实验,在确保每尾中国明对虾进食特定量WSSV毒饵后进行观察、分析.结果显示,分别喂食含5.2×108 copies、1.0×109copies、2.1×109 copies WSSV的毒饵,对虾平均存活时间分别是389.3、323.3和187.3 h,差异极显著(P＜0.01)；对虾最终累计死亡率都为100％.研究表明,致死量范围内,WSSV的感染量越低,对虾的平均存活时间越长.为了揭示饵料对中国明对虾抗病性能的影响,对已感染WSSV的中国明对虾投喂不同饵料.结果显示,分别喂食活卤虫、鲜蛤肉和配合饲料,对虾平均存活时间分别是281.7、173.9和164.9 h；喂食活卤虫的实验组平均存活时间显著高于喂食配合饲料和鲜蛤肉的实验组(P＜0.01)；喂食配合饲料和鲜蛤肉的对虾平均存活时间无显著差异(P＞0.05)；3组累计死亡率都为100％,结果表明,与配合饲料和鲜蛤肉相比,喂食活卤虫更能增强对虾抗WSSV的能力.%White spot syndrome virus(WSSV) is one kind of destructive virus affecting shrimp industry in the world. Output of Fenneropenaeus chinensis which once was a staple species has been greatly affected by outbreak of WSSV since 1993 in China. To produce WSSV-resistance shrimp strains is an important approach to revive the shrimp industry. To select survived F. chinensis as broodstock via WSSV challenge test can increase the efficiency of breeding. However, mortality of shrimps could reach nearly 100% once they were infected with WSSV, which increases the difficulty for shrimp breeding. In this study for the purpose to reveal effect of different WSSV amount on F. chinensis,juvenile F. chinensis were infected with a certain amount of WSSV individually and the survival time and survival rate were observed. The results showed that survival time of shrimps infected with 5. 2 x108 copies, 1. 0 x 109 copies and 2. 1 x 109 copies of WSSV respectively was 389. 3,323. 3 and 187. 3 h and significant different(P < 0. 01). The cumulative mortalities of all the shrimps finally reached 100% . The survival time increased while shrimps were fed with less WSSV bait. For the purpose to reveal the effect of diets on the ability for disease resistance, shrimps infected with WSSV were fed with different diets of live brine shrimps, commercial bait and fresh clam. It was showed that the survival time of infected shrimps fed with live brine shrimps, fresh clam and commercial bait respectively was 281. 7,173. 9 and 164. 9 h. The survival time of infected shrimp fed with live brine shrimps was significantly higher than that fed by commercial bait and fresh clam respectively (P <0.01). There was no significant difference of survival time between infected shrimps fed with commercial bait and fresh clam(P >0. 05). Cumulative mortalities of all the groups of infected shrimps that fed with different diets were 100% . Live brine shrimp is better than commercial bait and fresh clam for the purpose of enhancing shrimp WSSV resistance ability.