Effect of duration of cold stress on plasma adrenal and thyroid hormone levels and immune responses in chicken lines divergently selected for antibody responses
Hangalapura, BN × Nieuwland, MGB Buyse, Johan Kemp, B Parmentier, HK #
Poultry science assoc inc
Poultry science vol:83 issue:10 pages:1644-1649
There is increasing evidence that stress affects various immune processes. Some of these changes are due to hormonal changes involving corticosterone (CORT), triiodothyronine (T-3) and thyroxine (T-4). Effects of stress depend on the nature of specific stressors (e.g., thermal extremes, diet, pollutants), and stress-modifiers (e.g., genetic make-up, duration and severity of the stressors). We studied the effects of a specific stress (cold stress) with stress-modifiers (duration of stress and genotype of the bird) on immune responses and plasma adrenal and thyroid hormone levels in 3 layer-type chicken lines. Two lines were divergently selected for high (H line) or low (L line) antibody responses to SRBC, and the third line was a randombred control (C) line. Growing chicks (3- to 4-wk-old) of the 3 lines were feed-restricted at 80% of ad libitum consumption, and subjected to cold stress (CS) at 10degreesC continuously for 7, 5, 3, 1, or 0 d before immunization with keyhole limpet hemocyanin (KLH). Specific antibody titers to KLH, and in vitro lymphocyte proliferation (LP) upon mitogen stimulation were measured. In addition, adrenal and thyroid hormone levels were measured in the plasma samples collected at the end of CS.