Adrenocortical and heterophil/lymphocyte responses to challenge in hens showing short or long tonic immobility reactions.
1. Adult White Leghorn hens showing short or long tonic immobility reactions were classified as low-fear (LF) or high-fear (HF) responders, respectively. Following cannulation, their adrenocortical responsiveness to ACTH administration and the effects of chronic frustration induced by thwarting of feeding on plasma corticosterone concentrations and heterophil/lymphocyte (H/L) ratios were measured at regular intervals. 2. ACTH injection elicited significant and similar mean increases in circulating corticosterone concentrations in both the LF and HF groups. 3. Absolute H/L ratios were higher in HF than in LF hens after cannulation, although both groups showed similar proportional increases from pre-operation ratios. 4. Plasma corticosterone concentrations and H/L ratios were significantly increased at 20 h and 44 h respectively after the frustration of feeding regime began. Thus, adrenocortical activation preceded increases in H/L ratios but, whereas the elevated plasma corticosterone concentrations found after 20 h remained virtually constant thereafter, H/L ratios rose progressively throughout the 68 h frustration period. 5. There were no significant differences between groups in their plasma corticosterone and H/L responses to frustration. However, a consistent trend towards greater adrenocortical activation was observed in the HF than in the LF hens.
Beuving
G
G
Spelderholt Centre for Poultry Research and Extension, Beekbergen, The Netherlands.
Jones
R B
RB
Blokhuis
H J
HJ
D000302:Adrenal Cortex / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D001772:Blood Cell Count; D002645:Chickens / Q000097:blood / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D005239:Fear / Q000502:physiology*; D005260:Female; D005639:Frustration; D007103:Immobilization; D008214:Lymphocytes; D009504:Neutrophils; D013997:Time Factors
D000324:Adrenocorticotropic Hormone; D003345:Corticosterone