Model of physiological stress in chickens 1. Response parameters

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.