Jm. Trout et Mm. Mashaly, THE EFFECTS OF ADRENOCORTICOTROPIC HORMONE AND HEAT-STRESS ON THE DISTRIBUTION OF LYMPHOCYTE POPULATIONS IN IMMATURE MALE CHICKENS, Poultry science, 73(11), 1994, pp. 1694-1698
This study investigated the effects of heat stress and adrenocorticotr
opic hormone (ACTH) on the distribution of lymphocyte populations. Two
experiments were conducted; each used 12-wk-old Cornell K-strain male
chickens. In Experiment 1, birds were exposed to a temperature of 35
C, 6 h/d for 5 d and control birds were maintained at 24 C. In Experim
ent 2, birds received daily i.m. injections of 50 IU/kg body weight of
ACTH for 5 d and control birds received .9% saline. On Day 6, blood a
nd spleens were collected and lymphocytes were isolated. Indirect immu
nofluorescent labeling of lymphocytes were performed to detect B lymph
ocytes, CD4+ cells, and CD8+ cells. Neither ACTH injection nor heat st
ress affected percentages of B lymphocytes in the blood or the spleen.
The CD4+ cells decreased significantly in the blood of ACTH-injected
and heat-stressed birds and significantly increased in the spleens of
heat-stressed birds. The CD4+ cells in the spleens of ACTH-injected bi
rds did not differ from controls. The CD8+ cells significantly decline
d in the blood following both ACTH injection and heat stress and signi
ficantly increased in the spleen of the ACTH-injected birds but did no
t differ from controls in the heat-stressed birds. These results indic
ate that stress factors lead to redistribution of different lymphocyte
populations.