Zinc, copper, and iron metabolism during porcine fetal development

Abstract

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.

Effect of essential fatty acid and zinc supplementation during pregnancy on birth intervals, neonatal piglet brain myelination, stillbirth, and preweaning mortality1,2

“…Reports indicate that zinc concentrations in fetal blood are maximal Table 6. Least squares means (±SEM) for stomach contents, organ weights, and immunocrit values using birth weights as a covariate on d 60 and progressively fall throughout later gestation (Richards, 1999;Hostetler et al, 2003). This pattern is very similar to fetal serum iron concentrations (Vallet et al, 1996), and it is well known that piglets are born iron deficient (Ullrey et al, 1960).…”

Fluctuation of potential zinc status biomarkers throughout a reproductive cycle of primiparous and multiparous sows

“…MT in the liver removes Zn from the plasma and redistributes it to various tissues ( 15 , 23 , 32 ) . Hepatic MT synthesis is influenced by dietary Zn intake as well as plasma Zn concentrations ( 15 , 17 , 33 , 34 ) , suggesting that serum MT concentration reflects Zn absorption. This is confirmed in the present study, where serum MT concentration fluctuated similarly to plasma Zn concentrations during gestation but not at parturition when dietary Zn intake was low.…”

Effect of in-feed inclusion of a natural zeolite (clinoptilolite) on certain vitamin, macro and trace element concentrations in the blood, liver and kidney tissues of sows

“…The CLI extrusive rock was won and prepared by the company Silver & Baryte Ores Mining Co. (Athens, Greece). Recently, it has been authorized in accordance with Directive 70/524/EEC as additive in feeding stuffs intended for pigs, rabbits and poultry (binder, anti-caking agent and coagulant), under the conditions laid down in Annex II to this regulation (Commission Regulation No 1245/1999of 16 June 1999. One batch of this product was used and, according to the manufacturing company, the material's cation exchange capacity was 130±150 mEq 100 g À 1 , while its chemical composition (on dry sample) was: SiO 2 68Á26 per cent, Al 2 O 3 13Á30 per cent, Fe 2 O 3 0Á08 per cent, CaO 4Á34 per cent, MgO 1Á05 per cent, K 2 O 0Á94 per cent, Na 2 O 0Á26 per cent, L.O.I.…”