Protective immunity against enteric septicaemia in channel catfish, Ictalurus punctatus (Rafinesque), following controlled exposure to Edwardsiella ictaluri |
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| Authors: | C A Shoemaker,& P H Klesius |
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| Affiliation: | Agricultural Research Service, United States Department of Agriculture, Fish Diseases and Parasite Research Laboratory, Auburn, Alabama, USA,;Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama, USA |
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| Abstract: | Protective immunity against enteric septicaemia of catfish (ESC) following immunization with Edwardsiella ictaluri bacterins and exposure to live E . ictaluri was investigated. Mean cumulative percentage survival was significantly higher ( P 0.05) in controlled live vaccinates (100%) than in immersion and oral bacterin vaccinates (68.3% and 50.0%, respectively). Bactericidal activity against E . ictaluri by peritoneal macrophages from controlled live vaccinates (85.9%) was significantly greater ( P 0.05) than bactericidal activity of macrophages from immersion bacterin vaccinates (71.4%) or non-vaccinates (68.1%). No significant ( P > 0.05) difference was found in the bactericidal activity of macrophages from oral bacterin vaccinates and macrophages from controlled live vaccinates. The E . ictaluri -specific antibody response of controlled live (0.08 OD) and immersion bacterin vaccinates (0.11 OD) was significantly higher ( P 0.05) than that of oral bacterin vaccinates and non-vaccinates (0.01 OD) 15 days post-vaccination. A significantly higher antibody response was seen in controlled live vaccinates (0.17 OD), when compared to other vaccinates or non-vaccinates 33 days after vaccination. Neither immersion nor oral bacterins protected the vaccinates against ESC. Controlled live E . ictaluri immunization of channel catfish resulted in production of specific antibodies, increased macrophage bactericidal activity and protection against ESC. |
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