Efficacy of gel spray as a delivery system for turkey coccidiosis vaccine consisting of Eimeria adenoeides and E. meleagrimites

Eng H. Lee1 and R. Soares
Vetech Laboratories Inc., 131 Malcolm Road,
Guelph, Ontario, Canada, N1K 1A8

The first coccidiosis vaccine launched in the market, based on the theory of uniform exposure (Lee, 1986; Shirley & Long, 1990), was a carrageenan-based vaccine, which objective is to increase water viscosity and to maintain an even suspension of oocysts. This procedure was later adopted to produce a commercial product in the form of edible gel placed in the chick tray (Dasgupta & Lee, 2000). The idea of uniformity was also tested in the spray cabinet (Danforth, 1997) as water spray. This became popular because of its convenience. However, oocyst distribution before and after vaccination remains an issue. There is no problem in uniformity during stirring before spraying, but uniformity after spraying and before ingestion may be questionable. Here we report a gel spray delivery system using a gel diluent that may solve this problem.
Experiment 1: A turkey coccidiosis vaccine, containing Eimeria meleagrimitis and E. adenoeides, was administered to poults by one of three routes: gel spray, edible gel, or drinking water. Positive- and negative- control groups were included in the study. Poults were challenged with a high dose of turkey coccidia on day 15. Edible gel vaccine delivery provided the best protection , as measured byweight gain, against the challenge with turkey coccidia as compared to drinkingwater or spray delivery.. However, all three delivery routes significantly (p<0.03) prevented weight reduction as compared to non-vaccinated and challenged controls. When efficacy was measured as lesion score, vaccine delivered by gel spray or in drinking water produced better results than edible gel. We concluded that gel spray is a more efficient anti-coccidial vaccine delivery route, as measured by weight gain and lesion score, then drinking water or edible gel..
Experiment 2: Poults, which were vaccinated with the two Eimeria species vaccine and were challenged, gained more weight than non-vaccinated and challenged poults This weight gain was statistically significant (p<0.0093 for E. ad challenge, and p=0.0380 for E.me challenge ). Vaccinated and challenged poults had statistically significant lower (p<0.001) lesion scores as compared to non-vaccinated and challenged poults . We again concluded that poult vaccination by gel spray prevents weight gain reduction and also decreases morbidity as compared to unprotected and challenged controls.

1To whom correspondence should be addressed: elee@vetechinc.com