【作者】 刘相义；

【导师】 董双林；

【作者基本信息】 中国海洋大学 ， 水产养殖， 2005， 硕士

【摘要】 1.本研究利用PCR-斑点杂交和巢式PCR法检测野外发病对虾养殖池塘中桡足类及其休眠卵,以及由这些休眠卵孵化出的幼体携带病毒情况,发现桡足类由卵到成体各阶段中均有阳性个体,而且池塘中在春天放养对虾苗前桡足类就出现阳性个体。显示桡足类很可能是WSSV中间宿主和传播媒介,其休眠卵可能起到隔冬传播WSSV的作用。 2.分离池塘底泥中桡足类的休眠卵,进行孵化并培养,初步掌握了其中一种桡足类(克氏纺锤水蚤Acartia clausi)的培养条件和部分生物学特性,并进行了纯化培养,为进一步研究病毒传播途径提供充足的实验材料。 3.为证实携带WSSV的桡足类能否对养殖对虾起致病作用,用病毒粗提液浸泡和投喂两种方法分别对克氏纺锤水蚤进行人工感染,并用感染桡足类进行凡纳滨对虾投喂实验。巢式PCR检测发现浸泡攻毒克氏纺锤水蚤没有感染效果,投喂攻毒效果明显,而且用感染病毒的桡足类投喂对虾实验中对虾几乎全部检测为WSSV阳性。证明桡足类可以携带WSSV并作为传播媒介。另外从带毒桡足类所产的休眠卵及其孵化的幼体中也检测到WSSV阳性,显示桡足类休眠卵极可能是传播WSSV的载体和途径。 4.通过对桡足类及其休眠卵感染WSSV的调查及人工感染实验,证明了WSSV可以经口感染桡足类,并进而通过摄食途径感染对虾。桡足类休眠卵很可能是一种潜在的导致WSSV在世代间进行传播的媒介,携带WSSV的桡足类可造成对虾感染。实验结果显示,对虾养殖生产中,传统的清池方法不能有效切断WSSV的传播途径,这是导致WSS在一些对虾养殖池塘连年暴发的主要原因。寻找一种有效清除虾池中浮游动物休眠卵等潜在传播媒介的方法是防治WSSV的当务之急。更多还原

【Abstract】 1. In this study, copepoda and its resting eggs in shrimp culture ponds were detected using PCR dot-blot hybridization and nest-PCR for the presence of WSSV. The results showed that WSSV positive cases were detected in copepoda from egg to adult, and the positive copepoda appeared earlier than cultural shrimp in ponds. It may suggestted that copepoda was a WSSV host and transmission medium, and there may exist the transmission routes of WSSV through the resting eggs over winter.2. In addition, a kind of copepoda (Acartia clausi) was experimentally cultured, which from the resting eggs separated from the pond mud, then the cultural conditions and biological characters were partly mastered. A mass of copepoda were purely cultured to provide material for further studies.3. To testify whether WSSV could spread through copepoda to shrimp, two groups of adult copepoda were infected by two methods, soaking and feeding respectively, and fed to Litopenaeus vannamei using the copepoda carring WSSV. Soaking method didn’t work to spread WSSV to copepoda, while feeding method worked obviously, and in feeding experiment, nearly all shrimps were decteted WSSV positive by nest-PCR method. It showed adult copepoda could carry active WSSV particle and led to shrimp infection potentially. In addition, positive cases were also detected in the samples of the resting eggs and nauplii of copepoda, which indicated it was extremely possible WSSV could be vertically transmitted over winter by the resting eggs of copepoda.4. From the experiments, we might conclude that adult copepoda could carry WSSV and then infected shrimp through feeding, and that the resting eggs might be a kind of potential transmission medium to lead to WSSV transmit in different generations. Therefore, traditional shrimp culture should be reformed according to the WSSV transmission routes. Finding a method to kill out the resting eggs of zooplankton in shrimp pond may be in favor of the prevention of WSSV infection.更多还原