作者: M. A. Sutherland , S. R. Niekamp , S. L. Rodriguez-Zas , J. L. Salak-Johnson
DOI: 10.2527/2006.843588X
关键词:
摘要: Pigs typically experience various environmental stressors, which can negatively affect performance. Cortisol concentrations and immune performance measures are influenced by breed, but few data exist describing the impact of breed on stress responsiveness in pigs. The objective this experiment was to determine if certain physiological responses chronic stressors differed among 3 breeds 2 commercial lines pigs were Landrace (n = 36), Meishan 30), Yorkshire 32), or 1 (Line-A Line-B; both n 36). All weaned at 17 21 d kept a common nursery. At 49 age, assigned treatments: (heat, crowding, mixing) control (no treatment). allocated groups per pen same sex. Control with their littermates. onset experiment, stressed mixed unfamiliar once, heat crowding implemented simultaneously for 14 d. treatment video-recorded 24 h following initiation mixing social status: dominant, intermediate, submissive. Blood samples taken 0 (baseline), 1, 7, assess cortisol measures. Breed affected cortisol, immune, measures, no significant x interactions found. In general, subjected stressor had lower (P < 0.001) BW ADG than did Plasma 7 14. Regardless lipopolysaccharide-induced proliferation 0.01) natural killer (NK; P 0.005) cytotoxicity greater compared controls. Furthermore, pigs, dominant total white blood cell count 0.005), NK 0.05), phagocytosis 0.05) subordinate results indicate that pig not influence concurrent imposed study, status these heat, mixing.