Applied Research Note: Alpha-monolaurin stimulates the antibody response elicited upon infectious bronchitis vaccination of broilers

Alpha-monolaurin has been demonstrated to have antipathogenic properties and is therefore used as feed additive for broilers to prevent infectious diseases and improve production performance. As its antiviral effect is thought to be exerted by disintegrating the viral envelope, α-monolaurin might counteract with the current vaccination programs used in poultry production that are based on administering live attenuated viral strains. In this study, the effect of a commercially available formulation of α-monolaurin (FRAC12 Dry) on infectious bronchitis (IB) vaccination was evaluated in Ross 308 broilers. In chickens orally vaccinated with live infectious bronchitis virus (IBV), supplementation of FRA C12 Dry did not seem to affect the uptake of vaccine IBV, though indication for enhanced viral clearance of this virus was seen after 30 d in the supplemented birds. Furthermore, anti-IBV antibody titer values were significantly higher in orally IBV-vaccinated animals receiving FRA C12 Dry compared with the control group receiving blank feed. Taken together, the results indicate that α-monolaurin does not influence oral IB vaccination efficacy but, in contrast, has the potency to stimulate the immune response that is elicited upon vaccination. This further supports the use of α-monolaurin as a feed additive for broilers. Follow-up studies are, however, necessary to evaluate if better protection can be established upon challenge with IBV and whether a similar effect can be observed for other pathogens.