Department of Animal Science, Texas A&M University, 2471 TAMUS, College Station, TX 77843, USA.
Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA.
Domest Anim Endocrinol. 2021 Jan;74:106580. doi: 10.1016/j.domaniend.2020.106580. Epub 2020 Oct 10.
Maternal nutrient restriction during pregnancy alters fetal programming, which modifies the growth and health of the offspring in postnatal life. In cattle, nutrient restriction during pregnancy can be a result of environmental or economic factors, but little is known about how it alters the physiology of the fetus and affects future reproductive or growth efficiency. This study used female monozygotic twins, produced through in vitro fertilization and embryo splitting, to determine the effect of moderate maternal nutrient restriction on fetal development. Recipient Angus cross heifers pregnant with one twin were fed a diet meeting 100% National Research Council (NRC) total energy requirements (n = 4; control), whereas recipient heifers pregnant with the second twin were fed at 70% of NRC total energy requirements (n = 4; restricted) from gestational day (GD) 158 to GD 265 in Calan gate feeders. Recipient heifers were killed at GD 265. Change in maternal metabolic body weight was greater from zero in restricted heifers than controls (P < 0.05); restricted heifers lost weight during the nutrient restriction period. There was no difference in last rib back fat or rib eye area between groups (P > 0.10). There was no difference in fetal weight, uterine weight, or total placentome weight between groups (P > 0.10). The pancreas weight was reduced in restricted fetuses compared with control fetuses (P < 0.01), but there were no other differences in fetal organ weights (P > 0.10). Plasma insulin concentrations were reduced in restricted fetuses compared with controls (P < 0.01), but there was no effect of maternal diet on plasma glucose or glucagon concentrations in the fetus (P > 0.10). Histological analyses of the fetal pancreas revealed no differences in endocrine cell number or localization. Results indicate that a modest late gestation nutritional restriction impairs development of the fetal pancreas in the cow. Additional research will be needed to determine if these developmental changes lead to altered glucose and insulin homeostasis in the adult.
妊娠期间母体营养限制会改变胎儿的编程，从而改变后代出生后的生长和健康。在牛中，妊娠期间的营养限制可能是环境或经济因素的结果，但对于它如何改变胎儿的生理学以及如何影响未来的繁殖或生长效率知之甚少。本研究使用通过体外受精和胚胎分裂产生的雌性单卵双胞胎，来确定适度的母体营养限制对胎儿发育的影响。怀有一个双胞胎的受体安格斯杂交小母牛接受满足 100%国家研究委员会（NRC）总能量需求的饮食（n = 4；对照），而怀有第二个双胞胎的受体小母牛则从妊娠第 158 天（GD）至妊娠第 265 天（GD）在 Calan 门喂料器中以 NRC 总能量需求的 70%（n = 4；限制）喂养。受体小母牛在 GD 265 时被杀死。与对照组相比，限制组的母体代谢体重变化从 0 开始更大（P < 0.05）；限制组在营养限制期间体重减轻。两组之间最后肋骨背脂或肋眼面积没有差异（P > 0.10）。两组之间胎儿体重、子宫重量或总胎盘重量没有差异（P > 0.10）。与对照组相比，限制组胎儿的胰腺重量减轻（P < 0.01），但胎儿器官重量没有其他差异（P > 0.10）。与对照组相比，限制组胎儿的血浆胰岛素浓度降低（P < 0.01），但母体饮食对胎儿血浆葡萄糖或胰高血糖素浓度没有影响（P > 0.10）。胎儿胰腺的组织学分析显示内分泌细胞数量或定位没有差异。结果表明，适度的妊娠晚期营养限制会损害牛胎儿胰腺的发育。需要进一步的研究来确定这些发育变化是否导致成年后葡萄糖和胰岛素稳态的改变。
