Effects of weaning age on the behavioural and neuroendocrine development of piglets
Effects of weaning age on the behavioural and neuroendocrine development of piglets
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DOI：
10.1016/j.applanim.2007.03.018
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发表时间：
2008-03-01
影响因子：
2.3
通讯作者：
Lawrence, Alistair B.
中科院分区：
文献类型：
--
作者：
Jarvis, Susan;Moinard, Christine;Lawrence, Alistair B.
不良的早期生活经历可以永久地“编程”成年后的压力反应增加。我们调查了断奶，其中包括母亲分离，在不同的年龄，改变随后的行为，生理和神经内分泌功能的仔猪。将12头经产母猪的窝仔随机分为12日龄（W12）、21日龄（W21）和42日龄（W 42）断奶组。从11日龄至90日龄研究来自每窝的四个测试子代（n = 48，每个处理16）。在90日龄时，在剔除之前，每种处理的一半用束缚和隔离应激进行挑战。在所有组中，断奶后唾液皮质醇水平长期降低。W12和W21仔猪断奶后增重较慢，但到90天时，所有组的体重相似。在行为上，W12仔猪表现出更多的底物定向和攻击行为，姿势变化，鼻和腹鼻同窝仔。令人惊讶的是，W 42仔猪在28天时仍在母猪存在下表现出腹鼻的发作。在90日龄时，没有证据表明断奶年龄对下丘脑-垂体-肾上腺（HPA）轴有持续影响。束缚应激增加血浆促肾上腺皮质激素和皮质醇水平和CRH mRNA在下丘脑表明，断奶年龄的影响HPA功能的情况下，是不是由于天花板效应。这项研究是第一个使用行为，生理和神经内分泌措施相结合来研究断奶年龄对猪的长期影响。结果表明，断奶年龄的变化并没有明显的程序HPA轴，但有潜在的有害影响的行为肯定长达56天的年龄。然而，我们的研究在考虑断奶年龄的福利影响时也引起了并发症。具体来说，我们需要更多的信息的原因和长期影响的唾液皮质醇持续升高，我们观察到在哺乳期。断奶后期猪发生腹鼻也表明，在设计母猪和仔猪一起饲养超过28天的环境时需要注意。(c)2007 Elsevier B. V.保留所有权利。
Adverse early life experiences can permanently "programme" increases in stress reactivity in adulthood. We investigated whether weaning, which involves maternal separation, at different ages, altered subsequent behaviour, physiology and neuroendocrine function in young pigs. The litters of twelve primiparous sows were randomly allocated to weaning at 12 days (W12), 21 days (W21) or at 42 days (W42). Four test daughters from each litter (n = 48, 16 from each treatment) were studied from I I days of age until 90 days of age. At 90 days of age, prior to culling, half of each treatment were challenged with restraint and isolation stress. There was a long-term reduction in salivary cortisol levels following weaning in all groups. W12 and W21 piglets gained weight more slowly after weaning, but by 90 days weights were similar in all groups. Behaviourally, W12 piglets showed more substrate directed and aggressive behaviours, postural changes, and nosing and belly nosing littermates. Surprisingly, W42 piglets exhibited the onset of belly nosing at 28 days while still in the presence of the sow. At 90 days of age there was no evidence that weaning age had persisting effects on the hypothalamic-pituitary-adrenal (HPA) axis. Restraint stress increased plasma ACTH and cortisol levels and CRH mRNA in the hypothalamus demonstrating that the absence of weaning age effects on HPA function was not due to a ceiling effect. This study is the first to investigate long-term effects of weaning age in pigs using a combination of behavioural, physiological and neuroendocrine measures. The results suggest that variation in the age of weaning does not apparently programme the HPA axis but has potentially deleterious effects on behaviour certainly up to 56 days of age. However, our study also raises complications when considering the welfare implications of weaning age. Specifically more information is needed on the causes and long term implications of the sustained elevations of salivary cortisol we observed over the suckling period. The occurrence of belly nosing in later weaned pigs also suggests that care is required when designing environments where sows and piglets are housed together beyond 28 days. (c) 2007 Elsevier B.V. All rights reserved.