Otten Winfried, Puppe Birger, Kanitz Ellen, Schön Peter Christian, Stabenow Bernd
Research Unit Behavioural Physiology, Research Institute for the Biology of Farm Animals, 18196 Dummerstorf, Germany.
Physiol Behav. 2002;75(1-2):127-33. doi: 10.1016/s0031-9384(01)00630-8.
The impact of a 10-h social confrontation on behavior, plasma adrenaline, noradrenaline and cortisol was studied in 14 domestic pigs (eight castrated males and six females) with prior dominance experience. Prior to the experiments, animal groups, each consisting of nine growing pigs (12 weeks old) from different litters, were composed randomly. After 5 days, the pig with the highest rank from each group was removed, provided with a jugular vein catheter and kept in single housing for 2-3 weeks. After this period, each test animal was returned into its familiar group for a 10-h social confrontation. The reintroduction of the test animals into the familiar groups caused frequent agonistic interactions during the first 30 min. Seven animals succeeded to win most of their encounters during the confrontation test and were classified as High Success (HS) animals, whereas seven other animals lost most of their encounters and were classified as Low Success (LS) animals. The reintroduction of the test animals into the groups provoked also marked changes in behavioral and physiological measures. The frequent fighting behavior during the first 30 min was accompanied by a rapid increase of plasma catecholamines and a delayed increase of cortisol. Immediately after introduction, LS pigs tended to show higher plasma adrenaline and noradrenaline concentrations than HS pigs. There was also a tendency for a sustained increase of noradrenaline/adrenaline ratios in HS pigs, whereas the ratios of LS pigs remained nearly unchanged. No significant differences between both groups were found in cortisol levels and in the frequency of agonistic interactions. However, LS animals showed less locomotion, more lying and spent less time exploring the pen or other animals. These results show that during a social confrontation the experience of defeats for formerly high-ranking pigs is accompanied by increased submissive or passive behavior and a higher sympathoneural and adrenomedullary reaction, which may indicate more emotional distress and fear compared to successful animals.
在14头具有先前优势经验的家猪（8头去势雄性和6头雌性）中，研究了10小时社交对抗对行为、血浆肾上腺素、去甲肾上腺素和皮质醇的影响。在实验前，动物组由来自不同窝的9头生长猪（12周龄）随机组成。5天后，从每组中选出等级最高的猪，插入颈静脉导管，并单独饲养2 - 3周。在此之后，将每只试验动物放回其熟悉的组中进行10小时的社交对抗。将试验动物重新引入熟悉的组中，在最初的30分钟内引发了频繁的争斗互动。7只动物在对抗试验中成功赢得了大部分遭遇，并被归类为高成功（HS）动物，而另外7只动物输掉了大部分遭遇，被归类为低成功（LS）动物。将试验动物重新引入组中也引发了行为和生理指标的显著变化。最初30分钟内频繁的打斗行为伴随着血浆儿茶酚胺的快速增加和皮质醇的延迟增加。引入后，LS猪的血浆肾上腺素和去甲肾上腺素浓度往往高于HS猪。HS猪的去甲肾上腺素/肾上腺素比值也有持续增加的趋势，而LS猪的比值几乎保持不变。两组在皮质醇水平和争斗互动频率上没有显著差异。然而，LS动物的活动较少，躺卧较多，花在探索围栏或其他动物上的时间较少。这些结果表明，在社交对抗期间，以前等级较高的猪经历失败时，会伴随着顺从或被动行为的增加以及交感神经和肾上腺髓质反应增强，这可能表明与成功的动物相比，它们有更多的情绪困扰和恐惧。
