A model was developed to study stress in chickens. Continuous administratio
n of adrenocorticotropic hormone was employed (ACTH) using physiological mi
ni-osmotic pumps. A validation of controls for this procedure showed that n
onhandled (NHCON), sham surgical procedure for pump implantation (SMCON) an
d surgical implantation of a pump delivering saline (SAL-CON) were all acce
ptable controls. Continuous delivery of ACTH at 8 IU/kg BW/d for 7 d caused
increases in plasma corticosterone (CS), glucose (GLU), cholesterol (CHOL)
, triglycerides (TRI), high-density lipoprotein (HDL), total protein (TP),
and the heterophil/lymphocyte (H/L) ratio. Body weight, as well as relative
weights of the major immunobiological organs (i.e., spleen, thymus, and bu
rsa of Fabricius) were decreased. Finally, liver was increased due to lipid
and moisture accumulation. This model is the first to show in a single exp
eriment all the major adaptive stress responses of chickens.