Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

A comparison of immersion, immersion/oral combination and injection methods for the vaccination of channel catfish Ictalurus punctatus against Edwardsiella ictaluri.

Abstract

Four different vaccination regimes, including non-vaccinated controls (C), immersion/oral combination (IO), late immersion (LI) and injection (IJ), were evaluated for antibody production and protection from challenge in groups of 1500 channel catfish that were hatched and maintained in recirculating culture systems over 28 weeks. For IO, fry were vaccinated by immersion 12 days after hatching and given an oral booster in the 10th week after hatching. The LI and IJ delivered vaccine was also administered at 10 weeks after hatching. No antibody titres were detected in the IO group before the oral booster at week 10. Mean titres rose sharply after the week 10 vaccinations in all treatment groups, maintained a high level for about 8 weeks and slowly declined over the next 4 weeks. Injected fish had significantly higher titres during the primary response than either LI or IO fish. There was no statistical difference in titres between LI and IO fish during the primary response. After an oral booster delivered during the 22nd week after hatching, titres in LI and IO fish increased significantly at week 25, while titres in IJ fish declined despite the booster delivery. An immersion booster delivered during week 25 resulted in significant increases in titres in all vaccinated groups.