Efficacy of experimental animal and vegetable oil-emulsion vaccines for Newcastle disease and avian influenza.
Acceptable oil-emulsion vaccines were sought to replace mineral oil-emulsion vaccines that, by regulations, require a 42-day minimum holding period for poultry between injection and slaughter for consumption. Water-in-oil emulsions were prepared using animal or vegetable oils in a ratio of 4 parts oil to 1 part Newcastle disease or avian influenza aqueous antigen. Beeswax particles suspended in the oil at the 5% or 10% level (wt:vol) served as the oil-phase surfactant. Hemagglutination-inhibition titers induced by mineral-oil vaccines were not significantly different from those induced by the most efficacious formulations prepared from animal and vegetable oils. Tissue reaction from injection of animal- and vegetable-oil vaccines was less than that induced by mineral-oil vaccines. An inactivated avian influenza vaccine formulated from peanut oil induced protection against morbidity and death when vaccinated chickens were challenged with a virulent isolate of avian influenza virus.