Increased egg production in juvenile turkey hens after active immunizationwith vasoactive intestinal peptide

Juvenile turkey hens were actively immunized against vasoactive intestinal peptide (VIP) prior to photostimulation to evaluate its effect on enhancing egg production. VIP antibody titers were generated in the VIP immunized he ns and a greater rate of egg production per hen was observed compared to co ntrols. In addition, the first egg laying cycle was extended for an additio nal 7 wk without a significant decline in egg production. Over a 27-wk peri od, 116 settable eggs per hen were produced from the VIP immunized hens as compared to 102 and 90 eggs for the keyhole limpet hemocyanin and saline co ntrol groups, respectively. Based on the increased egg production and the e xtension of the first egg laying cycle, this experiment demonstrates that V IP immunization of turkey hens is potentially economically relevant.