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

本研究以鳗鲡消化道摄入牛血清白蛋白（BSA）作为口服免疫的基础。用牛血清白蛋白（BSA）溶液经肛门灌胃给鳗，用含BSA粉末的颗粒经口灌胃给鳗，用Ouchterlony法和SRID法检测血清用兔抗牛血清（BSA）作单向免疫扩散试验，Ouchterlony法显示抗血清与抗原（BSA）之间有沉淀线Ouchterlony法结果表明，BSA是从鳗鱼消化道摄入到血清中的，SRID试验结果表明，1.0ml鳗鱼血清中含有5.0-136.0 μ g BSA。口服含BSA的肠溶包衣胶囊，测定了两种胶囊（一种为直径为5 mm的大片剂型，另一种为微胶囊型）在鳗鱼血清中的BSA浓度。直径约为70 μ m，含BSA的中心包衣微囊给药显示更有效的结果-即实验鱼口服5 mg BSA微胶囊后，血清中的BSA可被SRLD检测到，而大胶囊和直接注射相同剂量的BSA，在所有试验鱼的血清中均未检测到，这一现象表明鳗鱼经口免疫的可能性，微囊包裹抗原对养殖鱼类免疫效果研究

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.