Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/2005
Publication Date: 2/16/2006
Citation: Shoemaker, C.A., Vandenberg, G., Desormeaux, A., Klesius, P.H., Evans, J.J. 2006. Delivery of a streptococcus iniae vaccine using oralject TM technology in tilapia oreochromis niloticus†. Aquaculture America Conference 2006. Las Vegas, Nevada. February 13-16, 2006. page 279.
Technical Abstract: This study evaluated the potential to orally deliver a previously developed Streptococcus iniae vaccine in tilapia using Oralject™ technology. This technology was developed to administer bioactive compounds to monogastric animals, and has been shown to be effective for delivery of a variety of antigens in numerous fish species. Two different formulations containing two doses of vaccine (four treatments) were fed to tilapia (4 tanks of 25 fish each) for one (Oralject A and Oralject C each containing 2 X 109 cells/g of feed) day (am and pm to satiation) or five (Oralject A and C each containing 2 X 108 cells/g of feed) days (once daily to satiation). The incorporated vaccine was a patented lyophilized modified bacterin (US Patent No. 6,379,677 B1). A positive control treatment [intraperitoneally (i.p.) injected S. iniae vaccine] and a negative control treatment (i.p. injection of tryptic soy broth) were included. Mean percent intake indicated that tilapia fed for one day (twice to satiation) the Oralject A consumed significantly (p < 0.05) more feed than fish fed Oralject C (4.05 vs. 3.21 %, respectively). Fish fed for 5 days either commercial feed or Oralject A or C also showed differences in feed intake. On most days, fish consumed significantly less (p < 0.05) Oralject C (~ 1%) than the commercial diet or Oralject A (~2.5 %). Tilapia were challenged 23 days post vaccination by i.p. injection of 1 X 106 CFU S. iniae/fish. Mean percent mortality was 47.5 (± 7.5) in the non-immunized challenged tilapia and was significantly higher (p < 0.001) than in all immunized groups. No mortality occurred in the i.p. vaccinated tilapia. Mortality ranged from 17.5 to 31.25 in the Oralject™ treatments. Relative percent survival was 100 % in the i.p. vaccinated tilapia and 63.1 % in the most effective Oralject-vaccine-treated group. The results demonstrate that oral delivery of lyophilized S. iniae vaccine using Oralject™ technology provided protection against streptococcal disease. These data validate an initial proof-of-principle for oral vaccination of tilapia using S. iniae in the Oralject™ system.