蚕卵高温即时浸酸阻断家蚕微粒子病胚种垂直传播的效果

Effect of High Temperature Instant Acid Treatment to Silkworm Eggs on Blocking Transovarial Transmission of Pebrine Disease

由家蚕微孢子虫（Nosema bombycis,Nb）感染引发的家蚕微粒子病可以通过胚种垂直传播,如能在蚕种人工孵化处理过程中杀灭家蚕微孢子虫,阻断其胚种传播,将有效控制病害对养蚕业尤其是蚕种制造业造成的危害。对家蚕二化性四元杂交组合两广二号的带毒卵进行高温即时浸酸处理,考察浸酸温度和浸酸时间对蚕卵中Nb的灭活作用及实用孵化率的影响。结果表明：产卵后20 h的带毒蚕卵用47.5℃或48℃质量浓度为1.075 g/m L的盐酸溶液分别浸渍6.0、6.5和7.0 min,对蚕卵实用孵化率无明显影响;依据蚕卵孵化后饲养至3龄眠蚕用显微镜镜检Nb的数据,测算高温即时浸酸处理对家蚕微粒子病的相对防治效果可达90%~97%。此外,采用Real-time PCR扩增方法,检测高温即时浸酸处理组蚕卵孵化蚁蚕样本中的Nb孢子目标基因的相对拷贝数,较常规浸酸处理组蚕卵孵化蚁蚕样本下降了97%~99%。上述结果表明高温即时浸酸处理对蚕卵中的Nb孢子有显著的杀灭作用,能有效阻断家蚕微粒子病的胚种垂直传播,可作为防治家蚕微粒子病的一种重要措施。

Pebrine disease caused by Nosema bombycis （Nb） could infect silkworm （ Bombyx mori） through vertical transmission from the mother hosts to their progenitive eggs. If Nb could be killed to block transovarial transmission during artificial hatching process of silkowrm eggs, the damage of pebrine to sericulture especially silkworm egg production would be effectively controlled. The effects of temperature and duration of acid treatment on Nb inactivation and on the practical hatching rate of silkworm eggs were investigated by high temperature instant acid treatment to infected silkworm eggs of the bivoltine quaternary hybrid combination Liangguang 2. The results indicated that there was no obvious effect on the practical hatching rate by immersing silkworm eggs （20 h after oviposition） in 47.5 or 48 ℃ HCI （1. 075 g/mL） for 6. 0, 6.5 and 7.0 min. According to the detected results of molting larvae of the 3rd instar under microscopy, the relative controlefficiency of high temperature instant acid treatment reac- hed 90%-97%. Besides, the relative copy numbers of Nb target genes in the newly-hatched larvae was detected by real-time PCR. Compared to conventional acid treatment, the relative copy numbers of Nb target genes reduced by 97%- 99% after high temperature acid treatment. The above results show that high temperature instant acid treatment has obvious effect on controlling the vertical transmission of pebrine disease and it can be used as an important measure to prevent and control pebrine disease.