Studies on ingestion of antigenic protein into the serum through the digestive tract of cultured fish

本研究对鳗鱼经消化道摄入血清中的牛血清白蛋白作为口服免疫的基础进行了研究。部分鳗鱼从肛门向肠道内注入牛血清白蛋白溶液，另一些鳗鱼经口向胃内注入含牛血清白蛋白微丸。用Ouchterlone法和兔抗牛血清白蛋白单径向免疫扩散试验对鳗鱼血清进行了检测。Ouchterlone法显示抗血清与牛血清白蛋白呈沉淀线。Ouchterlone法结果表明牛血清白蛋白是从鳗鱼的消化道摄入到血清中的，单径向免疫扩散试验结果表明1.0ml鳗鱼血清中含有5.0-136.0杯的牛血清白蛋白。口服含牛血清白蛋白(BSA)的包衣胶囊，测定了两种包衣胶囊的鳗鱼血清中牛血清白蛋白(BSA)的浓度，一种为大片，直径为5 mm，另一种为微囊型，直径约为70亩。以包被牛血清白蛋白(BSA)为囊芯的微胶囊给药效果更好，SRLD试验可检测到含BSA 5 mg的实验鱼血清中的BSA，而大胶囊和直接注射相同剂量BSA的实验鱼血清中均未检测到相同剂量的BSA。这些现象表明，鳗鱼经口服途径免疫的可能性和肠包被微胶囊对养殖鱼类抗原管理的有效性。

In the present study, ingestion of BSA(bovine serum albumin) into the serum through the digestive tract of eel was investigated as a basis of oral immunization. Some of eels were administrated experimentally with BSA solution into the gut from the anus and the other eels were administrated with pellet contained BSA powder into the stomach per os. Sera of eels were examined by Ouchterlony method and SRID (Single-radial- immuno-diffusion) test with the rabbit's antiserum against BSA.The Ouchterlony method showed precipitation line between the antiserum reacted with the antigen(BSA) and the serum of tested fish administrated with BSA by both route.Results of the Ouchterlony method suggested that BSA was ingested into the serum from digestive tract of eel, and results of the SRID test revealed that 1.0ml of serum of eel contained 5.0-136.0 mug of BSA. Oral administration of entric coated capsules contained BSA were examined BSA concentration in serum of eel for two types of capsules, one for large tablet type, 5mm in diameter and the other one for microcapsule type, 70 mu in diameter approximately.Administration of entric coated microcapsules contained BSA revealed more effective result-ie the sera of experimental fish orally administrated 5mg of BSA in microcapsule could be detected BSA by SRLD test, but in cases of large capsule and direct administration of the same dose of BSA could not be detected in any sera of tested fish.These phenomena suggested that possibility of immunization of eel by oral route and effectiveness of entric coated microcapsules for administration of antigen in cultured fish.