PREVENTION OF INCUBATION BEHAVIOR EXPRESSION IN TURKEY HENS BY ACTIVEIMMUNIZATION AGAINST PROLACTIN

The consequences of active immunization against prolactin on expressio n of incubation, reproductive performance and hormonal profiles were e valuated in turkey hens. Hens were injected weekly for 4 wk starting 8 wk before being submitted to a stimulatory photoperiod and 3 times th ereafter at intervals of 4 to 5 wk. The hens were injected id with 0.5 mi, of a mixture diluted half in Freund's adjuvant. The mixture was p rediluted in .9% saline and contained 100 mu g of a fusion protein (GS T-tPRL), GST, oPRL or vehicle. The results indicate that active immuni zations with GST-tPRL or oPRL both induce production of specific prola ctin antibodies. The onset of egg production was unaffected but higher egg production was observed for the GST-tPRL immunized hens. No GST-t PRL immunized hens expressed incubation behavior, whereas 20 to 30% of hens in the other experimental groups did so. Apparent hyperprolactin emia was detected by RIA for the GST-tPRL immunized groups starting be fore photostimulation and lasting until Week 10 of egg production but not in other groups. No significant differences were observed in eithe r plasma LH or estradiol concentrations of immunized and nonimmunized turkey hens. In conclusion, both GST-tPRL or oPRL induced the producti on of antibodies against prolactin in turkey hens. However, only activ e immunization using GST-tPRL induced higher antibody titers as well a s full prevention of incubation behavior expression. Such a pharmacolo gical approach is of great practical interest, although its uses need to be carefully evaluated under commercial conditions. (C) 1998 by Els evier Science Inc.