Stress Response Dynamics in Acth and Formalin Treated Chickens

MONEVA, P., S. POPOVA-RALCHEVA, D. GUDEV, V. SREDKOVA and I. YANCHEV, 2008. Stress response dynamics in ACTH and formalin treated chickens. Bulg. J. Agric. Sci., 14: 598-605 This study was conducted with fifteen chickens (White Plymouth rock pure initial line from the National Genetic Resource) at the age of seven weeks which were randomly allocated into three groups: I experimental groupinjected (i.m.) with 1-24 ACTH (Synacthen Depot)., 8 μg.kg-1B.W.; II experimental groupinjected with 0.5 ml formalin (15% formaldehyde); III group (control) injected with 0.5 ml 0.9% NaCl. They were raised in cages (5 chicks per cage). The chickens were injected at 9h a.m after 2 h period of fasting. Blood samples were obtained by venipuncture of wing vein at 1h, 3h, 5h and 24h after the injection. The objective of this study was to establish: 1).Is ACTH the main secretagogue of the adrenal glands in chickens and 2).The effect of formalin on adrenal glands in chickens. Plama corticosterone (CS) level increased 7-fold in ACTH-treated birds (P<0.05) at 1h after the injection while in formalin treated birds it increased only 2-fold. At 3h after the injection there was a sharp drop in corticosterone level in ACTH treated group, (P<0.05) , but in formalin treated chickens the values were higher (P<0.05) compared to those in ACTH treated chickens. Heterophil-to-lymphocyte (H:L) ratio rose at 3h (P<0.01) and 5h (P<0.05) in ACTH treated chickens, while in formalin treated chickens tended to be higher (P>0.05) at 5h following the injection. Hematocrit (at 1h) and erythrocyte numbers (at 3h) following the injection were elevated (P<0.05) in both groups. Leukocyte numbers increased significantly (P<0.05) at 1h in formalin treated chickens and tended to be higher (P>0.05) in ACTH treated birds. ACTH did not cause any significant elevation in Il-1α concentration in both groups. However, Interleukin-1α level in the formalin treated chickens tended to be higher at 1h (P>0.05) and was significantly lower at 24 following the injection. Plasma cholesterol levels increased significantly at 1h and returned to baseline levels at 3h after the injection of ACTH. Formalin treatment caused insignificant decline of cholesterol levels at 3h and 5h after the injection. Urea levels were significantly elevated in ACTH treated chickens at 1h (P<0.01), 3h (P<0.01) and 5h (P<0.05) and in formalin treated chickens at 24h following the injection. Plasma glucose levels were significantly elevated both in ACTH (P<0.001) and formalin (P<0.001) treated chickens throughout the experimental period. In conclusion: Adrenal responsiveness to ACTH and the negative feedback in chickens is similar to that in mammals. Formalin is less potent stimulator of adrenal glands than ACTH and exerts a definite effect on leukocyte numbers and Il1α level.