PREVENTION OF THE EXPRESSION OF INCUBATION BEHAVIOR USING PASSIVE-IMMUNIZATION AGAINST PROLACTIN IN TURKEY HENS (MELEAGRIS-GALLOPAVO)

The efficacy of injecting antibodies raised against turkey prolactin t o prevent the expression of incubation behaviour has been investigated in turkey hens. Medium white turkey hens (n = 15 x 2) were injected t hree times weekly for 4 consecutive weeks starting on week 5 of egg pr oduction. The hens were injected im with a volume of 1 mL per injectio n for the 1st week and 0.5 mL thereafter, of normal rabbit serum or se rum containing antibodies raised against turkey prolactin (Guemene et al, 1994a). None of the 15 passively immunised hens expressed incubati on behaviour, whereas, more than half (53%) of the control hens did ex press it. Plasma prolactin concentrations observed in the two groups p resented comparable profiles until week 9 and from week 19 of egg prod uction onward. Differences were, therefore, observed from week 10 unti l week 17 with the non immunised hens showing higher plasma prolactin concentrations than the immunised ones. This difference was related to the presence of incubating hens in the control group. A higher percen tage of non immunised hens disrupted egg production during the course of the study and consequently immunised hens laid more eggs than the c ontrol ones. No change in plasma LH and estradiol concentrations can b e related to the immunisation procedure. We conclude that prevention o f incubation behaviour can be achieved using passive immunisation agai nst prolactin, prevention which resulted in more egg production under our experimental protocol.