Open AccessThe Relationship Between Vaccine Dose and Efficacy in Channel Catfish Ictalurus punctatus Vaccinated as Fry with a Live Attenuated Strain of Edwardsiella ictaluri (RE‐33) 1
Author(s) -
Wise David J.,
Terhune Jeffery S.
Publication year - 2001
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.2001.tb01092.x
Subject(s) - edwardsiella ictaluri , ictalurus , catfish , vaccination , biology , attenuated vaccine , virulence , veterinary medicine , fish <actinopterygii> , zoology , microbiology and biotechnology , virology , fishery , medicine , biochemistry , gene
Channel catfish Ictalurus punctatus were vaccinated at 12 d of age (post‐hatch) by a 2‐min bath immersion with attenuated Edwardsiella ictaluri RE‐33 at doses of 2.5 × 10 5 , 2.5 × 10 6 , and 2.4 × 10 7 colony‐forming units CFU/mL of water. Following vaccination, RE‐33 was recovered from a greater percentage of fry that were vaccinated at the high and intermediate doses compared to fry vaccinated at the lowest dose. Independent of dose, the greatest percentage of RE‐33 positive fry occurred between 1 and 6 d post‐vaccination with a significant decrease in positive fry observed on day 12. A significant increase in mortality occurred 6 to 12 d post‐vaccination in fry vaccinated at the highest dose. No differences in post‐vaccination mortalities occurred between the other treatments. Following virulent E. ictaluri challenge, mortalities of fish vaccinated at doses of 2.5 × 10 6 and 2.4 × 10 7 CFU/mL were significantly less than those of fish vaccinated at 2.5 × 10 5 CFU/mL and sham‐vaccinated control fish. These data show that vaccination with RE‐33 can offer protection against subsequent virulent E. ictaluri infection.