|Cheng, Heng Wei|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/4/2007
Publication Date: 6/15/2007
Citation: Fahey, A.G., Marchant Forde, R., Cheng, H. 2007. Genetic Basis of different Effects of Chronic Intermittent Social Stress on Immune Function and Survivability in laying hens [abstract]. Poultry Science Association Meeting Abstract. p. 362. Interpretive Summary:
Technical Abstract: Chronic social stress has a large impact on animals’ susceptibility to disease. This study was designed to examine the effects of genetic selection, and genotype-by-environmental interactions on chicken immune parameters and longevity. Chickens from HGPS (selected for high production and survivability, also called KGB, kind gentle birds previously) and DXL (Dekalb XL, a commercial strain) were used in this study. Chickens were housed in 8-bird cages (213 cm2/bird). From 30 - 45 wks of age, two birds were moved weekly among the cages within the same genetic line to create a social instability, called chronic intermittent social stress. Blood sample, body weight (BW), and several organ weights were collected from birds at 45 wks of age. Circulating subsets of T lymphocytes: CD4+ and CD8+ were measured using flow cytometry. Concentrations of plasma corticosterone were detected using radioimmunoassay (RIA). Results showed that DXL hens had a heavier adrenal weight (both absolute and relative weight) (P<0.05) than HGPS hens, while there were no differences in the body weight and weights of the spleens and livers between DXL and HGPS hens (P>0.05). Compared to the HGPS hens, DXL hens also had a higher portion of CD8+ cells (P<0.01), resulting in a lower CD4+:CD8+ ratio (P<0.05). There were no significant differences for plasma concentrations of corticosterone between the hens from DXL and HGPS lines (P>0.05). Results also showed that DXL hens had a higher mortality than HGPS hens (P<0.01). The data suggests that, compared to HGPS hens, chronic intermittent social stress may adversely affect the immune function and survivability of DXL hens. The results indicate that, similar to other animals, there are heritable components in chickens’ disease resistance and stress response, which is regulated differently by genotype-by-environment interactions.