Richards M P
U.S. Department of Agriculture, Agricultural Research Service, Livestock and Poultry Sciences Institute, Growth Biology Laboratory, Beltsville, MD 20705, USA.
Biol Trace Elem Res. 1999 Jul;69(1):27-44. doi: 10.1007/BF02783913.
Zinc, copper, and iron levels in maternal and fetal pig tissues and fluids were measured starting on d 30 of gestation and continuing to term (d 114) at 10-d intervals. Fetal hematocrit increased from a low of 19% on d 30 to 32% by d 50, after which it remained above 30% to term. Amniotic fluid zinc, copper, and iron all reached maximal levels by d 60 of gestation. Maternal serum zinc levels fluctuated little during gestation, but fetal serum zinc concentration was significantly elevated above maternal levels during the second trimester. Fetal serum copper levels were significantly lower than maternal values throughout gestation and this was also the case for ceruloplasmin oxidase activity. Maternal serum iron reached its lowest level by d 80 of gestation when rate of transfer of iron to the developing fetuses was high. Fetal serum iron declined throughout gestation, reaching its lowest level on d 100. In general, fetal liver concentrations of zinc, copper, and iron were higher than the corresponding maternal values throughout gestation. Distinct increases were noted for fetal hepatic zinc and copper concentrations during the second trimester of pregnancy and these were accompanied by increases in cytosolic and metallothionein-bound zinc and copper levels. Maternal hepatic iron declined during the second trimester, reaching its lowest point on d 80, indicative of the shunting of maternal iron reserves to fetal tissues. Fetal kidney metal levels did not demonstrate any distinctive developmental patterns with respect to zinc, copper, or iron concentrations, but a general accumulation of each metal was observed as gestation progressed. The results of this study highlight some of the distinct changes occurring in the metabolism of zinc, copper, and iron in both maternal and fetal tissues and fluids during gestation in the pig.
从妊娠第30天开始，每隔10天测量母猪和胎儿组织及体液中的锌、铜和铁含量，直至足月（第114天）。胎儿血细胞比容从妊娠第30天的低水平19%增加到第50天的32%，此后一直保持在30%以上直至足月。羊水锌、铜和铁在妊娠第60天均达到最高水平。妊娠期间母猪血清锌水平波动较小，但在妊娠中期胎儿血清锌浓度显著高于母猪水平。整个妊娠期间胎儿血清铜水平显著低于母猪，铜蓝蛋白氧化酶活性也是如此。妊娠第80天，母猪血清铁达到最低水平，此时铁向发育中的胎儿的转移速率较高。胎儿血清铁在整个妊娠期间下降，在第100天达到最低水平。一般来说，整个妊娠期间胎儿肝脏中的锌、铜和铁浓度高于相应的母猪水平。在妊娠中期，胎儿肝脏锌和铜浓度明显增加，同时细胞溶质和金属硫蛋白结合的锌和铜水平也增加。妊娠中期母猪肝脏铁含量下降，在第80天达到最低点，表明母猪铁储备向胎儿组织的分流。胎儿肾脏金属含量在锌、铜或铁浓度方面未表现出任何独特的发育模式，但随着妊娠进展，观察到每种金属都有普遍积累。本研究结果突出了猪妊娠期间母猪和胎儿组织及体液中锌、铜和铁代谢发生的一些明显变化。
