The effect of perch access on physiological homeostasis during the life cycle of white leghorns.

Feifei Yan, Purdue University

Abstract

Egg laying strains of chickens have a strong motivation to perch. Providing caged chickens with perches allows them to perform their natural perching instinct and also improves their musculoskeletal health due to exercise. Little is known about the effect of perch access by chickens on physiological homeostasis. The neuroendocrine system controls animals' adaptability to their environments by releasing psychotropic compounds such as catecholamines (epinephrine, norepinephrine, and dopamine), corticosterone, and serotonin. Changes of these compounds have been used as biomarkers of animals' stress responses associated with their well-being. The objective of this study was to determine the effect of perch access during all or part of life cycle on physiological homeostasis in caged White Leghorns. Treatments during the pullet phase included 14 cages each with and without perches from hatch to 16.9 wk of age. At 17 wk of age, White Leghorn pullets were randomly assigned to 1 of 4 treatments with 9 replicates per treatment. Treatment 1 chickens never had access to perches during their life cycle. Treatment 2 chickens had access to perches only during the pullet phase (hatch to 16.9 wk of age). Treatment 3 chickens had access to perches only during the egg laying phase (17 to 71 wk of age).Treatment 4 chickens always had access to perches during their entire life cycle (hatch to 71wk of age). Stress related physiological and physical parameters were measured during the pullet phase at 4, 6, and 12 wk of age and at the end of lay at 71 wk of age, including plasma concentrations of EP, NE, DA, and CORT; blood levels of 5-HT and tryptophan; adrenal weights; heterophil to lymphocyte ratio; shank width and length; and fluctuating asymmetry of shanks.. With the exception of shank width, none of the parameters measured in the current study differed due to perch treatments during either the pullet or laying phases. Hens at 71 wk of age with previous exposure to perches as pullets had wider shanks than hens that did not have perches as pullets (P = 0.01), providing supporting evidence that perching activity early in life increased musculoskeletal size of legs. These results suggest that installation of perches in conventional cages did not induce stress in White Leghorns.

Degree

M.S.

Advisors

Hester, Purdue University.

Subject Area

Animal sciences|Environmental Studies|Behavioral Sciences

COinS