INOVOCOX™ ONSET OF IMMUNITY AFTER IN OVO DELIVERY TO BROILERS
V. W. Doelling, R. M. Poston, C. L. Heggen-Peay, G. F. Mathis2,
A. Martin, J. R. Upton, and L. M. Charniga.
1Embrex Inc., P. O. Box 13989, Research Triangle Park, NC 27709
2Southern Poultry Research, Athens, GA 30607
vdoelling@embrex.com
Broiler eggs
were vaccinated in ovo at 18 days of embryonation with Inovocox™, a
coccidiosis vaccine consisting of live sporulated oocysts of E. acervulina, E.
tenella and two strains of E. maxima. Vaccine safety was demonstrated by
comparable percent hatch for vaccinates and non-vaccinated controls. At hatch,
chicks were vent-sexed and male chicks were selected. Birds were placed in 5
floorpens per treatment with 45 birds per pen. To assess efficacy, a subset of
birds (5 per pen; 25 per treatment group) were weighed and orally challenged
with mixed Eimeria sp (homologous strains) on days 14, 21/22, 28, and 35. Six
days post challenge, birds were individually weighed and lesions evaluated in
the upper, mid, and cecal regions of the intestines. Results indicated a
progression in development of immunity over time. Following challenge,
statistical improvement in weight gain and some decrease in lesion formation was
observed as early as day 14. By day 21/22, full immunity was achieved with
improved weight gain and lower lesion scores for all Eimeria species
demonstrated in vaccinated birds when compared with non-vaccinated birds. These
data establish that in ovo vaccination with live oocysts is safe and efficacious
in broiler chickens.