The biological basis for prenatal programming of postnatal performance in pigs.
The biological basis for prenatal programming of postnatal performance in pigs.
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DOI：
10.2527/2006.8413_supple105x
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发表时间：
2006-04
影响因子：
3.3
通讯作者：
G. Foxcroft;W. Dixon;S. Novak;C. T. Putman;S. Town;M. Vinsky
中科院分区：
文献类型：
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作者：
G. Foxcroft;W. Dixon;S. Novak;C. T. Putman;S. Town;M. Vinsky
本综述的主要目的是讨论出生体重的窝内变异与猪断奶前存活率和出生后生长之间的关系，作为建议出生的猪的发育能力以及窝的大小需要认真考虑的基础。极端的宫内生长迟缓（IUGR）发生在一个离散的胎儿亚群中，远小于其同窝仔，通常被描述为矮小仔猪。矮小猪的较低的断奶前生长不能完全根据它们较低的出生体重来解释，它们也没有表现出完全的出生后补偿性生长。有趣的是，这种更复杂的发育重编程已经可以在妊娠第27至35天发现。最近，我们报道了更普遍的IUGR的影响，在商业坝线母猪，作为一个间接的选择增加产仔数。较高产次母猪的高排卵率（>30次排卵）与存活至妊娠第30天的孕体数量增加有关，导致着床后早期子宫拥挤对胎盘发育产生不利影响。反过来，这限制了胚胎在肌生成的关键时期的营养可用性。因此，尽管在第50天出现了孕体数量的减少，但存活胎儿的胎盘发育仍然受到损害，导致IUGR，并在第90天和出生时减少了所有存活同窝仔的肌纤维数量。子宫拥挤对胎儿和产后发育的影响类似于妊娠母猪营养限制对胎儿肌生成、出生体重和产后生长的不利影响。在子宫容量没有增加的情况下，存活至着床后阶段的孕体数量增加之间的不相容性，为产次较大母猪中报告的出生体重和产后生长性能变异性增加提供了生物学解释。我们的结论是，引入高繁殖力的女性到育种核心的策略，作为一种手段，增加出生的猪的数量，需要严格评估的背景下，猪肉生产的整体效率。
The main purpose of this review is to discuss associations between within-litter variation in birth weight, and preweaning survival and postnatal growth in the pig, as the basis for suggesting that the developmental competence of pigs born, as well as the size of the litter, need critical consideration. Extremes of intrauterine growth retardation (IUGR) occur within a discrete subset of fetuses, substantially smaller than their littermates and commonly described as runt piglets. The lower preweaning growth of runt pigs cannot be entirely explained based on their lower birth weight, nor do they show full postnatal compensatory growth. Interestingly, this more complex reprogramming of development in runt pigs can already be identified by d 27 to 35 of gestation. Recently, we reported more universal IUGR effects in commercial dam-line sows, as an indirect response to selection for increased litter size. High ovulation rates (>30 ovulations) in a proportion of greater parity sows are associated with increased numbers of conceptuses surviving to d 30 of gestation, resulting in detrimental effects on placental development of uterine crowding in the early postimplantation period. In turn, this limits nutrient availability to the embryo during a critical period of myogenesis. Consequently, although a reduction in the number of conceptuses occurs by d 50, placental development in the surviving fetuses remains compromised, resulting in IUGR and reduced numbers of muscle fibers at d 90 and at birth, in all surviving littermates. These effects of uterine crowding on fetal and postnatal development are analogous to the detrimental effects of nutritional restriction in gestating sows on fetal myogenesis, birth weight, and postnatal growth. The incompatibility between increased numbers of conceptuses surviving to the postimplantation period, in the absence of increased uterine capacity, offers a biological explanation for increased variability in birth weight and postnatal growth performance reported in greater parity sows. We conclude that a strategy of introducing hyperprolific females into the breeding nucleus, as a means of increasing the numbers of pigs born, needs to be critically evaluated in the context of the overall efficiency of pork production.