减毒沙门氏菌为载体的口服生长抑素DNA疫苗对草鱼的安全性

幼草鱼灌服10^8、10^9、10^10cfu／mL减毒沙门氏菌为载体的口服生长抑素DNA疫苗ZJ111／pcDNA3-SS，另设野生型鼠伤寒沙门氏菌（10^9cfu／mL）和PBS对照组，试验期20d，观察并比较各组死亡率。另取150g左右的草鱼灌服PBS、10^8cfu／mL ZJ111／pcDNA3-SS和10^8cfu／mL野生型鼠伤寒沙门氏菌组，7d后屠宰取肝和脾脏，做透射电镜切片观察。结果显示，灌服10^9cfu／mL ZJ111／pcDNA3-SS的幼鱼在试验期间死亡2尾，灌服10^8cfu／mL ZJ111／pcDNA3-SS和PBS的幼鱼采食和生长正常，灌服野生型S．typhimurium和10^10cfu／mL ZJ111／pcDNA3-SS的幼鱼死亡率分别为76．67％、26．67％。灌服10^8cfu／mL ZJ111／pcDNA3-SS的草鱼肝、脾细胞形态正常，肝脏线粒体略微肿胀，内质网间距略有增大，但病变特征不明显；10^8cfu／mL的zJ111／pcDNA3-SS对草鱼具有相对安全性。

Safety of an Oral Somatostatin DNA Vaccine Using Attenuated Salmonella typhimurium as Carrier for Grass Carp

The juvenile grass carps were fed with somatostatin DNA vaccines using attenuated Salmonella typhimurium as carrier(ZJ111/ZJ111/pcDNA3-SS,10~8,10~9,10~(10) cfu/mL) through oral route to evaluate the survival of fishes in comparison to S.typhimurium(10~9 cfu/mL) and PBS as controls.In another experimental setting,larger grass carps(body weight of about 150 g) fed with 1 mL of ZJ111/pcDNA3-SS(10~8 cfu/mL),S.typhimurium(10~8 cfu/mL) and PBS.The liver and spleen was taken 7 days post-fedding,for electronic microscopic analyses.Mortalities of juvenile grass carps fed with the strain ZJ111/pcDNA3-SS at 10~8,10~9 and 10~(10) cfu/mL were 0%,6.67% and 26.67% respectively.The morphology of cells of liver and spleen was normal from the fishes fed with ZJ111/pcDNA3-SS and PBS while there were apoptotic changes in the liver and spleen cells of fishes fed with wild type S.typhimurium.These results indicated that oral administration of ZJ111/pcDNA3-SS at the dose of 10~8 cfu/mL was relatively safe for the carps.