Department of Biological Sciences, Lehigh University, 111 Research Drive, Bethlehem, PA 18015, USA.
Department of Biology, Susquehanna University, Selinsgrove, PA 17870, USA.
Integr Comp Biol. 2017 Dec 1;57(6):1245-1257. doi: 10.1093/icb/icx108.
Maternal programming of offspring energy balance has been viewed as an adaptation in which the gestational environment prepares the offspring to thrive and reproduce in that same postnatal environment. Programming might have the opposite effect, however, when gestational and postnatal environments are mismatched. Gestational programming would represent a trade-off if the mother can maximize fitness in one possible energetic future but cannot maximize fitness in another. The vast majority of research concerns rats, mice, or sheep, and dams are typically food restricted by 30-70% of ad libitum intake resulting in low birth weight and adult obesity in offspring. Few previous studies have used a lower level of food restriction, and no experiments, to the best of our knowledge, were designed to determine whether the effects of gestational restriction have postgestational effects independent of the effects that occurred during gestation. In the present experiment, Syrian hamsters were either restricted to 90% of their ad libitum food intake or fed ad libitum during pregnancy. All litters were cross-fostered at birth and all were fed ad libitum during lactation. Half of the litters from ad libitum-fed pregnant dams were fostered to dams that had been food restricted during pregnancy and half of the litters from food-restricted pregnant dams were fostered to ad libitum-fed dams. The latter group allowed us to test the hypothesis that the effects of having a gestationally food-restricted mother affects offspring characteristics independent of the prenatal programming. First, we found significant increases in the postnatal body weight of the offspring of ad libitum-fed mothers fostered to food-restricted dams, supporting the hypothesis that the effects of gestational restriction carry over to postnatal maternal ability (e.g., milk yield, milk content, or parental behavior). Second, the carry-over effects of gestational food restriction on offspring postnatal body weight were significant in male but not female offspring. This occurred even though this group had significantly lower food intake than offspring of ad libitum-fed mothers with ad libitum-fed foster mothers. In addition, and contrary to expectation, gestational food restriction had no significant effect on adult baseline food hoarding or food hoarding in response to food restriction. These results suggest that even mild energetic challenges during gestation can have postgestational effects on maternal ability, and the effects on offspring are sex-specific.
母体对子代能量平衡的编程被视为一种适应，其中妊娠环境使后代能够在同一产后环境中茁壮成长和繁殖。然而，如果妊娠和产后环境不匹配，编程可能会产生相反的效果。如果母亲可以在一种可能的能量未来中最大限度地提高适应性，但不能在另一种能量未来中最大限度地提高适应性，那么妊娠编程将代表一种权衡。绝大多数研究都涉及大鼠、小鼠或绵羊，并且母鼠通常通过 30-70%的自由进食摄入量来限制饮食，导致后代出生体重低和成年肥胖。以前很少有研究使用较低水平的饮食限制，而且据我们所知，没有实验旨在确定妊娠限制的影响是否在妊娠期间发生的影响之外具有产后影响。在本实验中，叙利亚仓鼠要么被限制在其自由进食摄入量的 90%以内，要么在怀孕期间自由进食。所有的窝仔都在出生时被交叉寄养，并且在哺乳期都自由进食。自由进食的怀孕母鼠的一半窝仔被寄养给怀孕期间限制饮食的母鼠，而限制饮食的怀孕母鼠的一半窝仔被寄养给自由进食的母鼠。后一组让我们测试了这样一个假设，即有一个在妊娠期间限制饮食的母亲会影响后代的特征，而这些特征独立于产前编程。首先，我们发现自由进食的母鼠的后代在被寄养给限制饮食的母鼠后，其产后体重显著增加，这支持了这样一个假设，即妊娠限制的影响会延续到产后母亲的能力（例如，产奶量、奶成分或父母行为）。其次，妊娠期饮食限制对后代产后体重的后续影响在雄性后代中是显著的，但在雌性后代中却不是。这甚至发生在这一组的食物摄入量明显低于自由进食的母鼠与自由进食的寄养母鼠的后代的情况下。此外，与预期相反，妊娠期饮食限制对成年期基础食物囤积或对食物限制的食物囤积没有显著影响。这些结果表明，即使在妊娠期间经历轻微的能量挑战，也会对母代的能力产生产后影响，并且对后代的影响是性别特异性的。
