Geverink N A, Schouten W G P, Gort G, Wiegant V M
Human and Animal Physiology Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
Physiol Behav. 2002 Nov;77(2-3):451-7. doi: 10.1016/s0031-9384(02)00877-6.
Several recent studies on pigs have demonstrated a relationship between the degree of resistance displayed early in life in a so-called backtest and a variety of behavioural and physiological responses in piglets and young fattening pigs. To study whether pigs with diverging responses in the backtest, i.e., high-resisting (HR) and low-resisting (LR) pigs, differ also in adulthood in their responses to an acute stressor, adult nulliparous HR (n=36) and LR gilts (n=36) housed in groups or stalls were challenged by 5-min fixation with a nose sling. During the first minute of restraint, HR gilts vocalised significantly more than LR gilts. Over the whole 5-min period, HR gilts tended to vocalise more than LR gilts. Housing or backtest type did not affect immediate cortisol increase (Delta(-5 min; 15 min)). At t=45 min, cortisol concentrations in HR gilts but not in LR gilts were still higher than at t=-5 min. Heart rate quickly decreased during the first min of restraint and remained fairly constant thereafter. Estimated heart rate after 5 min of nose sling was significantly lower in HR gilts compared to LR gilts. Housing or backtest type did not affect heart rate variability indices. The results support the idea that the backtest relates to individual characteristics, which at an adult age also seem to play a role in the regulation of certain behavioral and physiological responses to short-term stress.
最近几项针对猪的研究表明，在所谓的回测中仔猪早期表现出的抵抗程度与仔猪和幼龄育肥猪的多种行为和生理反应之间存在关联。为了研究在回测中反应不同的猪，即高抵抗性（HR）猪和低抵抗性（LR）猪，在成年后对急性应激源的反应是否也存在差异，将成年未育的HR母猪（n = 36）和LR母猪（n = 36）成组或单栏饲养，用鼻吊固定5分钟进行应激挑战。在约束的第一分钟内，HR母猪发出的声音明显多于LR母猪。在整个5分钟期间，HR母猪发出的声音往往比LR母猪更多。饲养方式或回测类型不影响皮质醇的即时升高（Δ（-5分钟；15分钟））。在t = 45分钟时，HR母猪的皮质醇浓度仍高于t = -5分钟时，而LR母猪则不然。心率在约束的第一分钟内迅速下降，此后保持相当稳定。鼻吊固定5分钟后，HR母猪的估计心率显著低于LR母猪。饲养方式或回测类型不影响心率变异性指标。这些结果支持了这样一种观点，即回测与个体特征有关，而这些特征在成年时似乎也在调节对短期应激的某些行为和生理反应中发挥作用。
