Effects of selenium supply and dietary restriction on maternal and fetal body weight, visceral organ mass and cellularity estimates, and jejunal vascularity in pregnant ewe lambs.

Center for Nutrition and Pregnancy, Animal and Range Sciences Department, North Dakota State University, Fargo, USA.
Journal of Animal Science (Impact Factor: 1.92). 10/2007; 85(10):2721-33. DOI: 10.2527/jas.2006-785
Source: PubMed

ABSTRACT To examine effects of nutrient restriction and dietary Se on maternal and fetal visceral tissues, 36 pregnant Targhee-cross ewe lambs were allotted randomly to 1 of 4 treatments in a 2 x 2 factorial arrangement. Treatments were plane of nutrition [control, 100% of requirements vs. restricted, 60% of controls] and dietary Se [adequate Se, ASe (6 microg/kg of BW) vs. high Se, HSe (80 microg/kg of BW)] from Se-enriched yeast. Selenium treatments were initiated 21 d before breeding and dietary restriction began on d 64 of gestation. Diets contained 16% CP and 2.12 Mcal/kg of ME (DM basis) and differing amounts were fed to control and restricted groups. On d 135 +/- 5 (mean +/- range) of gestation, ewes were slaughtered and visceral tissues were harvested. There was a nutrition x Se interaction (P = 0.02) for maternal jejunal RNA:DNA; no other interactions were detected for maternal measurements. Maternal BW, stomach complex, small intestine, large intestine, liver, and kidney mass were less (P < or = 0.01) in restricted than control ewes. Lung mass (g/kg of empty BW) was greater (P = 0.09) in restricted than control ewes and for HSe compared with ASe ewes. Maternal jejunal protein content and protein:DNA were less (P < or = 0.002) in restricted than control ewes. Maternal jejunal DNA and RNA concentrations and total proliferating jejunal cells were not affected (P > or = 0.11) by treatment. Total jejunal and mucosal vascularity (mL) were less (P < or = 0.01) in restricted than control ewes. Fetuses from restricted ewes had less BW (P = 0.06), empty carcass weight (P = 0.06), crown-rump length (P = 0.03), liver (P = 0.01), pancreas (P = 0.07), perirenal fat (P = 0.02), small intestine (P = 0.007), and spleen weights (P = 0.03) compared with controls. Fetuses from HSe ewes had heavier (P < or = 0.09) BW, and empty carcass, heart, lung, spleen, total viscera, and large intestine weights compared with ASe ewes. Nutrient restriction resulted in less protein content (mg, P = 0.01) and protein:DNA (P = 0.06) in fetal jejunum. Fetal muscle DNA (nutrition by Se interaction, P = 0.04) concentration was greater (P < 0.05) in restricted ewes fed HSe compared with other treatments. Fetal muscle RNA concentration (P = 0.01) and heart RNA content (P = 0.04) were greater in HSe vs. ASe ewes. These data indicate that maternal dietary Se may alter fetal responses, as noted by greater fetal heart, lung, spleen, and BW.

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    ABSTRACT: To determine the impacts of Se supply and maternal dietary intake on ewe organ mass and endocrine and metabolic changes throughout gestation, pregnant first parity ewes (n=77) were allocated to 6 treatments in a 2×3 factorial array. Factors included Se [adequate Se (ASe; 9.5μg/kg BW) vs. high Se (HSe; 81.8μg/kg BW)] initiated at breeding and dietary intake [60% (RES), 100% (CON), or 140% (EXC) of requirements] initiated on d 50 of gestation. Ewes were individually fed and blood samples from the jugular vein were obtained approximately every 14 d from d 50 until parturition. Maternal Se supply did not impact endocrine or metabolic status. There was a nutritional intake by day interaction for NEFA, blood urea nitrogen (BUN), insulin, triiodothyronine (T3), thyroxine (T4), progesterone (P4), and estradiol-17β (E2). As expected, with increased maternal intake, NEFA concentrations were reduced. During the last weeks of gestation, BUN and insulin were elevated in EXC compared with RES ewes. Although the pattern of T3 and T4 differed throughout gestation within a treatment group, as maternal intake increased, circulating T3 and T4 were increased. For P4 and E2, as maternal dietary intake increased, there was a reduction in the steroid concentrations in jugular blood. There was only a main effect of maternal nutrition (P<0.001) for cortisol concentrations with EXC ewes having greater concentrations than RES and CON ewes, which did not differ. Although Se is known to influence thyroid hormone metabolism, supranutritional levels during pregnancy did not alter circulating T3 and T4 concentrations. Alterations in maternal endocrine status may have influenced placental transport of nutrients to the developing fetus, which we have shown previously is affected by maternal dietary Se and intake. In addition, the alterations in mammary gland weight that we observed may explain the impact of maternal nutrition on mammary gland function and colostrum production, thereby further impairing growth of developing neonates.
    Animal reproduction science 08/2013; · 1.56 Impact Factor
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    ABSTRACT: In Experiment (Exp.) 1, western whiteface ewes (n = 32; BW = 45.6 ± 2.2 kg) were allotted to one,of four treatments in a ,completely ,randomized ,design ,to examine,effects of maternal,dietary Se and source on fetal jejunal crypt cell proliferation. Maternal diets contained (DM basis) no added ,Se (control) or supranutritional Se included as high-Se wheat (SW) and sodium ,selenate (S3 and,S15). Treatments were ,initiated at 50 ± 5 d of pregnancy. The control, SW, S3, and S15 diets provided 2.5, 75, 75, and 375 µg Se/kg BW, respectively. On day 134 ±10 of pregnancy, ewes and lambs were necropsied and tissues were harvested. In Exp. 2, western whiteface ewes (n = 36; BW = 53.8 ± 1.3 kg) were allotted to treatments in a 2 x 2 factorial arrangement,to examine effects of maternal nutrition and ,dietary Se on ,fetal jejunal crypt ,cell proliferation and ,vascularity. Treatments were ,maternal nutrition (100% of requirements ,[CON] vs. 60% of CON [RES]) and dietary Se (6 µg Se/kg BW/d [ASe] and 80 µg Se/kg BW/d [HSe]) from Se enriched ,yeast. Selenium treatments were initiated 21 d before breeding and maternal nutrition treatments began on d 64 of gestation. On d 135 ± 5 of gestation, ewes and lambs were necropsied and tissues harvested. In Exp. 1, maternal nutrition did not affect (P =
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    ABSTRACT: To determine the effects of maternal supranutritional selenium (Se) supplementation and maternal nutritional plane on offspring growth potential, ewes were randomly assigned to 1 of 6 treatments in a 2 × 3 factorial arrangement [dietary Se (adequate Se; 9.5 μg/kg body weight vs. high Se; 81.8 μg/kg body weight initiated at breeding) and plane of nutrition [60%, 100%, or 140% of requirements; initiated on day 50 of gestation]]. Lambs were immediately removed from dams at birth and reared. Cortisol concentrations at birth were similar, but by 24 h, a relationship (P = 0.02) between maternal Se supplementation and nutritional plane on cortisol concentrations was observed in lambs. A sex of offspring × day of age interaction (P = 0.01) and a maternal Se supplementation × nutritional plane × day of age interaction (P = 0.04) was observed for thyroxine concentrations. Differences in growth may be influenced by thyroid hormone production early in neonatal life.
    Nutrition and Metabolic Insights 01/2013; 6:11-21.

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