Location: Livestock Behavior ResearchTitle: Effects of perch access on physiological parameters in caged White Leghorn pullets Author
|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2013
Publication Date: 11/1/2013
Citation: Yan, F., Hester, P.Y., Enneking, S.A., Cheng, H. 2013. Effects of perch access on physiological parameters in caged White Leghorn pullets. Poultry Science. 92(11):2853-2859. Interpretive Summary: Egg laying strains of chickens have a strong motivation to perch. However, perch use by chickens in grower cages has received little attention. The objective of this study was to determine the effect of perch access on physiological parameters in caged White Leghorn pullets. Two parallel metal round perches were installed in each of 14 cages assigned the perch treatment, while 14 control cages were without perches. The data were collected randomly from two chickens per cage at 4, 6, and 12 wk of age, respectively. Results showed there was no perch effects on the parameters measured in this study. These parameters, such as corticosterone and heterophil to lymphocyte ratio, have been used as stress indicators in chickens. The data suggested that modification of conventional cages with perches did not cause stress in pullets. These results can be used by egg producers to develop management practices for improving pullet welfare by providing perches.
Technical Abstract: The neuroendocrine system controls animals' adaptability to their environments by releasing psychotropic compounds such as catecholamines [epinephrine (EP), norepinephrine (NE), and dopamine (DA)], corticosterone (CORT), and serotonin (5-HT). Changes of these neuroendocrine compounds have been used as biomarkers of animals' stress responses associated with their well-being. The aim of this study was to examine the effects of perch access on the physiological homeostasis of White Leghorn pullets housed in conventional cages. A total of 1,064 hatchlings were randomly assigned to 28 cages. Two parallel metal round perches were installed in each of 14 cages assigned the perch treatment, while control cages were without perches. Two birds per cage were sacrificed at wk 4, 6, and 12 wk of age. Plasma levels of CORT, DA, EP, and NE, blood concentrations of 5-HT, tryptophan (TRY), and heterophil to lymphocyte (H:L) ratios were measured. The EP:NE ratios were calculated. Data were analyzed using two-way ANOVA. The perch treatment or its interaction with age did not affect any parameter measured in the study. With the exception of DA and CORT, concentrations of hormones were generally lower at 12 wk of age as compared to levels at 4 and 6 wk of age (P = 0.0007 or less). In contrast, concentrations of DA were less at 4 wk as compared to 6 and 12 wk of age (P < 0.0001). Plasma CORT levels and the H:L ratio were unaffected by age (P = 0.07 and 0.49, respectively). These results indicated that age but not perch access affects neuroendocrine homeostasis in White Leghorn pullets. The data suggest that modification of conventional cages with perches did not cause stress in birds.