鲈鱼口服生物胶囊疫苗的研究

以暴发弧菌病的鲈鱼 (Lateolabraxjaponicus)鱼苗体内分离的 1株病原菌W 1(Vibrioanguillarum)为材料 ,分别以直接浸浴法、创伤后浸浴法和肌肉注射法人工感染鲈鱼鱼苗。结果表明 ,这三种感染方式均能使鲈鱼发病 ,其半致死浓度 (LD50 )分别为2 75× 10 7cfu/ml ,4 .68× 10 6cfu/ml和 3.72× 10 5cfu/尾。在此基础上 ,分别以福尔马林灭活法和喷雾干燥法制备了全细胞疫苗和微胶囊疫苗。将全细胞疫苗及微胶囊疫苗以直接拌入饵料法和卤虫携带法等两种方法口服免疫接种鲈鱼鱼苗 ,一周后以W 1活菌攻毒( 2 50× 10 6cfu/尾 )。结果表明 ,各免疫组一周的累积死亡率远低于两组对照组 ( 95% )。其中 ,以卤虫携带的生物微胶囊疫苗组的一周累积死亡率最低 ,为 2 5.0 % ;以卤虫携带的生物全细胞疫苗组的一周累积死亡率较高 ,为 60 .0 %。因而 ,以卤虫携带的生物胶囊疫苗组的免疫保护力最高 ,为 73.7% ,其次为微胶囊疫苗直接投喂组 ,保护力为 56.8%。直接投喂和卤虫携带法的全细胞疫苗也显示了一定的免疫效果 ,其免疫保护力分别为 52 .6%和 36.8%。

Oral vaccination of Seaperch (Lateolabrax japonicus), Against Vibrio ang uillarum Using Bioencapsulated Vaccine

Challenge tests to sea perch fries challenged by the virulent strain of Vibrio a nguillarum (W-1) initially isolated from diseased sea perch (Lateolabrax ja ponic us) were investigated. The fries were seriously infected by the means of bacte ri al bath, bacterial bath after injury, injecting by muscle, their LD50 were 2.75 ×107cfu/ml, 4.68×106cfu/ml and 3.72×105cfu/fish, respectively. Then, th e heal th sea perch fry were orally vaccinated for 5days consecutively using two vacci ne s by the means of adding directly into food or bioencapsulation of Artemia naupl ii. The two vaccines, one is the microcapsulated vaccine (MC), the other is whol e cell bacterin (WC). The results showed the cumulative mortality of all 4 vacci ne groups were rather lower than those of control groups. The group of Artemia n auplii carrying microcapsulated vaccine had the highest relative percentage surv ival (RPS) in the all 4 vaccine-groups after a challenge test by injecting viab l e W-1 a week later, was 73.7%, the group of microcapsulated vaccine by adding di rectly into food was the second, its RPS was 56.8%. The rest two whole cell bact erin groups, one was directly adding into food, the other was carried by Artemia nauplii, their RPS were 52.6%, 36.8% respectively.