Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2003
Publication Date: 6/17/2003
Citation: Cheng, H., Lay Jr, D.C., Pajor, E. 2003. Adrenergic regulation of immunity in laying hens. Poultry Science. 82(1):60.
Technical Abstract: The ability of the adrenergic system to regulate chickens' immune function was examined. Clonidine, an alpha-2 adrenergic receptor agonist, was administrated at 2.5, 5 or 10 mg/L in drinking water of White Leghorn hens at 48 wk of age (n=64), randomly housed in conventional cages in pairs (645 cm2 of floor space/hen). Concentrations of plasma IgG were detected using chicken IgG ELISA (Bethel Laboratories, Inc), and subsets of peripheral blood lymphocytes were analyzed using Flow Cytometry (Coulter XL MCL, Coulter Inc). Compared to controls, treated hens had greater concentrations of plasma IgG and number of peripheral blood B cells (ANOVA, P<0.01) after 1 week of treatment. There was a consistent tendency for the number of CD 8+ T cells to increase but not for CD 4+ T cells in treated hens (t-test, P=0.07). The clonidine-induced increases in immune response were dose related, and the highest increases were found in the hens treated with 10 mg/L (t-test, P<0.05). These results suggest that the adrenergic system is directly involved in regulating chicken's immunity, especially, the humoral immunity, by acting on alpha-2 receptors located on lymphocytes. A future study needs to examine whether supplementing clonidine to laying hens can be effective in reducing infection and inflammation when the immune system is challenged.