论文部分内容阅读
鉴于海豚链球菌已成为我国罗非鱼养殖发病死亡最主要的病原菌,本研究利用临床分离菌株对低剂量(1.5×105CFU.mL-1)攻毒耐过罗非鱼进行再次攻毒试验,筛选到1株具有很好交叉免疫保护的疫苗候选菌株CMS005,甲醛灭活制备成疫苗分别通过注射、浸泡及口服免疫罗非鱼。室内水族箱免疫试验中,注射、浸泡和口服三种免疫途径各自的最佳免疫保护率分别为90.5%、61.9%和14.3%;池塘小网箱免疫试验结果为100%、86.1%和66.7%。数据分析显示,相同剂量注射组免疫保护率明显高于浸泡免疫组与口服免疫组;免疫剂量对浸泡免疫和口服免疫效果的影响大于注射免疫;同时加强免疫可显著提高浸泡免疫与口服免疫效果;超声波处理也可提高浸泡免疫效果。生产小试结果表明,未免疫组罗非鱼月累计死亡率在6%~15%之间,而免疫组罗非鱼月累计死亡率不到0.5%;注射免疫和口服免疫效果相当,免疫7d和15d后均可完全控制罗非鱼海豚链球菌病的继续发生;疫苗发生的免疫保护力可持续2~3个月。上述结果表明,所研制的预防罗非鱼海豚链球菌病疫苗具有很好免疫效果及生产应用前景。
In view of that S. dolphin has become the most important pathogen of trophic death in tilapia farming in our country, this study used the clinical isolates to re-challenge the low-dose (1.5 × 105CFU.mL-1) To a strain of vaccine candidate strain CMS005 with good cross-protection, inactivated by formaldehyde, the vaccine was prepared as a vaccine to immunize tilapia by injection, immersion and oral administration respectively. In the indoor aquarium immune test, the best immune protection rates of injection, immersion and oral administration were 90.5%, 61.9% and 14.3% respectively. The results of immunization of small pond cage were 100%, 86.1% and 66.7% . Data analysis showed that the immune protection rate of the same dose injection group was significantly higher than that of the soaking immunization group and the oral immunization group; the immunization dose had more influence on the soaking and the oral immunization effect than that of the immunization; strengthening the immunization at the same time significantly increased the soaking immunity and the oral immunization effect; Ultrasound treatment can also improve the immune effect of soaking. The results of the production trial showed that the cumulative mortality of tilapia was 6% -15% in the non-immunized group, while the cumulative mortality of tilapia in the immunized group was less than 0.5% in a month. The vaccination and oral immunization effects were comparable, And 15d after the complete control of tilapia dolphin streptococcal disease can continue to occur; vaccine protective immunity can last 2 to 3 months. The above results show that the prevention of tilapia dolphin streptococcal vaccine has a good immune effect and production and application prospects.