Comparison of inactivated Newcastle disease viral vaccines containing different emulsion adjuvants.

Chickens inoculated with inactivated-virus Newcastle disease vaccines containing different emulsion adjuvants were challenge exposed with viscerotropic velogenic Newcastle disease virus. Adjuvant activity was evident in all of 9 vaccines containing mineral oil emulsion (OE), but was not evident in 2 vaccines which contained a metabolizable lipid emulsion (LE) adjuvant consisting of peanut oil, glycerol, and lecithin. Serologic responses of chickens inoculated with OE vaccines were 10- to 100-fold higher than those of chickens inoculated with LE vaccines. One of 106 chickens given OE vaccine, 12 of 24 given LE vaccine, and all of 24 nonvaccinated control chickens were clinically affected or died after challenge exposure. Five OE vaccines emulsified only by brief vigorous shaking had adjuvant activity similar to 4 OE vaccines emulsified by conventional homogenization.