The aim of this experiment was to study the effect of in ovo injection of royal jelly (RJ) on growth perform-ance and immune response in broiler chickens challenged with Newcastle disease virus. A total of 200 hatching eggs were divided into four groups of 50 eggs each one using a completely randomized design. The eggs were injected with sterilized sodium bicarbonate buffer (pH=10.4) or RJ (88%) in a 0.3 mL vol-ume into the albumen at d 7 of incubation. A non-injected control and a dry punch control (shell pricked without injecting solution; needle) were included. Chicks hatched from the respective treatment group were reared in floor pens until d 28. The chickens were challenged against Newcastle disease virus on days 7 and 21. On d 21, the chickens emanated from the RJ injected egg had the highest body weight. In ovo injection of RJ had a significant effect on feed intake in broiler chickens during starter period (d 1 to 21) and throughout the trial (d 1 to 28; P<0.05). On d 14, serum antibody titer against Newcastle disease virus (NDV) was not significantly different among treatments. On d 14 and 28, heterophil and lymphocyte num-ber and their ratio were affected by in ovo injection. In conclusion, the results of the present study suggested that in ovo injection of RJ on d 7 of incubation exerted a beneficial effect on growth in starter phase and could stimulate feed intake in broiler chickens challenged with Newcastle disease virus, although the antibody titer against NDV was not influenced.
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