Plasma prolactin responses to serial bleeding in turkeys

Abstract

Changes in plasma prolactin (PRL) in response to serial bleeding by venipuncture were measured in turkeys of varying age, sex and reproductive condition. Serial bleeding increased plasma PRL levels in immature, ovariectomized (OVX), laying and non-laying females, but depressed PRL levels in broody (incubating) females. Immature males showed a positive PRL response, while mature males showed no significant response to serial bleeding. The effective stressor was shown to be repeated capture and restraint for serial bleeding and not blood loss. The pattern of the PRL response in OVX hens was not significantly influenced by variations in time required for capture and restraint or by variation in the fear reaction to capture. Habituation of OVX hens to serial capture and handling on 14 consecutive days did not significantly blunt the PRL response to serial bleeding. These results reaffirm the importance of understanding the role of physiological and psychological factors influencing PRL secretion in birds as well as the need to avoid undue stress in birds used for studies of PRL secretion.