Litter-size-dependent intrauterine growth restriction in sheep

Gootwine, E.; Spencer, Thomas E.; Bazer, Fuller W.

doi:10.1017/s1751731107691897

Cited by 73 publications

(63 citation statements)

References 144 publications

(130 reference statements)

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“…This indicates that by the end of gestation a synchronous reduction of both the fetus and the placenta has occurred as number of fetuses increased. While it is unknown in the current study when this reduction in both fetal and placental sizes may have occurred, it has been reported that individual fetal weight gain begins to decrease with increased fetal numbers at day 100 of gestation, while placental weights by day 70 in twin and triplet pregnancies are already reduced compared to singleton pregnancies [39]. Furthermore, placental efficiency in singleton compared to multiple pregnancies was not different, indicating that the relationship between fetal weight to placental weight was similar in singleton and multiple pregnancies.…”

Section: Discussionmentioning

confidence: 62%

“…Moreover, VEGF protein expression within the placentome decreased with increased numbers of fetuses. While all ewes in the current study were slaughtered at a similar time point relative to breeding, it is known that gestation length in ewes carrying multiples is reduced compared to singleton [39]. This may have impacted the discrepancies between the mRNA and protein expression of angiogenic factors investigated in this study.…”

Section: Discussionmentioning

confidence: 98%

“…Furthermore, Zheng and coworkers [27] reported VEGF localized to placental endothelial cells. Decreases in VEGF may impact NO production necessary for vasodilation [40], causing a stress and initiating the parturient process earlier in multiple pregnancies compared to singleton pregnancies [39]. However, this subject requires further investigation.…”

Section: Discussionmentioning

confidence: 99%

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Placental vascularity and growth factor expression in singleton, twin, and triplet pregnancies in the sheep

Vonnahme

Evoniuk

Johnson

et al. 2008

Endocr

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For singleton, twin, and triplet pregnancies, uteri were collected on day 140 of pregnancy. For each ewe (n = 18), placentomes were fixed by arterial perfusion supplying the fetal (cotyledon) and maternal placenta (caruncle). Tissue sections were stained for determination of vascularity by image analysis. Further, protein expression for factor VIII, vascular endothelial growth factor (VEGF) and its receptor, VEGFR1, as well as basic fibroblast growth factor (FGF2) and its receptor, FGFR, in tissue sections was determined by immunohistochemistry and image analyses. Cotyledonary and caruncular samples were analyzed for expression of mRNA for Vegf and its two receptors, Vegfr1 and Vegfr2, as well as Fgf2 and Fgfr. Fetal number did not affect placental capillary density or factor VIII expression, whereas increased fetal number reduced total cotyledon and caruncle capillary volume. While expression of Vegf, Vegfr1, Vegfr2, and Fgfr mRNA in cotyledonary but not caruncular tissue was greater in twin pregnancies compared to singleton and triplet pregnancies, protein expression of VEGF in the placentome decreased with increasing numbers of fetuses, VEGFR1 did not change, and FGFR was greater in twin versus singleton and triplet pregnancies. Fetal number did not affect the expression of Fgf2 mRNA in placental tissues, whereas FGF2 protein expression was less in triplet compared to singleton and twin pregnancies. Reduced fetal and placental weights in twins and/or triplet pregnancies are associated with an overall decrease in total placental vascularity, VEGF and FGF2 and/or FGFR protein expression, but not in angiogenic factor mRNA expression or VEGFR1 protein expression in sheep.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Placental vascularity and growth factor expression in singleton, twin, and triplet pregnancies in the sheep

Vonnahme

Evoniuk

Johnson

et al. 2008

Endocr

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“…In several prolific breeds of ewes, increases in litter size adversely affect fetal growth and lamb survival even though ewes are maintained under intensive management conditions (see Gootwine et al 2008;Gootwine 2013). Prenatal fetal death associated with intrauterine fetal growth restriction (IUGR) and difficulties during lambing are primary causes of lamb mortality (Gootwine et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Amino Acids and Conceptus Development During the Peri-Implantation Period of Pregnancy

Bazer

Johnson

2015

Advances in Experimental Medicine and Biology

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The dialogue between the mammalian conceptus (embryo/fetus and associated membranes) involves signaling for pregnancy recognition and maintenance of pregnancy during the critical peri-implantation period of pregnancy when the stage is set for implantation and placentation that precedes fetal development. Uterine epithelial cells secrete and/or transport a wide range of molecules, including nutrients, collectively referred to as histotroph that are transported into the fetal-placental vascular system to support growth and development of the conceptus. The availability of uterine-derived histotroph has long-term consequences for the health and well-being of the fetus and the prevention of Developmental Origins of Health and Disease (DOHAD). Although mechanisms responsible for differential growth and development of the conceptus resulting in DOHAD phenomena remain unclear, epigenetic events involving methylation of DNA are likely mechanisms. Histotroph includes serine and methionine which can contribute to the one carbon pool, and arginine, lysine and histidine residues which may be targets of methylation. It is also clear that supplementing the diet with arginine enhances fetal-placental development in rodents, swine and humans through mechanisms that remain to be elucidated. However, molecules secreted by conceptuses such as interferon tau in ruminants, estrogens and interferons in pigs and chorionic gonadotrophin, along with progesterone, regulate expression of genes for nutrient transporters. Understanding mechanisms whereby select nutrients regulate expression of genes in cell signaling pathways critical to conceptus development, implantation and placentation is required for improving successful establishment and maintenance of pregnancy in mammals.

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“…alterations in foetal nutrition, which can be due to changes in dam nutrition, may result in permanent changes in the structure, physiology, metabolism, and post-natal growth of the offspring (Wu et al 2006). However, any such effect is dependent on the type and timing of the nutritional insult (Mellor 1983;Robinson et al 1999;Redmer et al 2004;Gootwine et al 2007;Symonds et al 2007). Jenkinson (2006) reported that foetal mammary gland development was affected by dam nutritional regimen beginning day 21 of gestation.…”

Section: Introductionmentioning

confidence: 99%

The effect of ewe size and nutritional regimen beginning in early pregnancy on ewe and lamb performance to weaning

Kenyon

Jenkinson

et al. 2009

New Zealand Journal of Agricultural Research

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Ewe size, pregnancy nutrition and pregnancy rank are known to affect the productive performance of ewes and their offspring. The aim of the present study was to compare the effects of two nutritional regimens, from day 21 to day 140 of pregnancy, in singleton-and twin-bearing ewes of two different mean weights, taken from a single flock. The study included Large ewes offered Ad lib (Large-Ad lib, n= 151), Large ewes offered Maintenance (Large-Maintenance, n = 153), Small ewes offered Ad lib (Small-Ad lib, n = 155) and Small ewes offered Maintenance (Small-Maintenance, n = 153) that were either singleton-or twin-bearing. During the period day 21 to day 140 Maintenance and Ad lib feeding regimens included Large and Small ewes and singleton-and twin-bearing ewes. At days 1 and 140 of pregnancy Large ewes were heavier (P < 0.05) and of greater (P < 0.05) body condition than Small ewes. Similarly, at days 1 and 140 of pregnancy twin-bearing ewes were heavier (P < 0.05) than single-bearing ewes. At day 1 of pregnancy there was no difference in ewe liveweight and body condition scores between Maintenance and Ad lib-fed ewes, but by day 140 ewes in the Ad lib regimen were heavier (P < 0.05) and had greater (P < 0.05) body condition than Maintenance ewes. There was an interaction (P < 0.05) between ewe nutritional regimen and lamb birth rank for lamb birth weight such that twin lambs born to Maintenance regimen ewes were lighter (P < 0.05) than their counterparts born to Ad lib ewes (4.52 ± 0.06 versus 5.23 ± 0.06 kg respectively). This relationship was not observed in singletons. There was also an interaction (P < 0.05) between ewe size and nutritional regimen for lamb birthweight. Birth weights did not differ between lambs born to either Small or Large ewes on the Ad lib feeding regimen. However, lambs born to Small ewes on the Maintenance feeding regimen were lighter (P < 0.05) than their counterparts born to Large ewes (5.09 ± 0.07 versus 5.37 ± 0.07 kg respectively). At day 100 of lactation lambs born to Large ewes were heavier (P < 0.05) than those born to Small ewes (32.65 ± 0.37 versus 31.16 ± 0.35 kg respectively) and those born to Ad lib ewes were heavier (P < 0.05) than those born to Maintenance ewes (32.77 ± 0.37 versus 31.03 ± 0.36 kg respectively). This study shows that level of dam pregnancy nutrition has a greater effect on twin-born lambs than their singleton-born counterparts. Furthermore, the data suggests that the heavier liveweights at weaning of lambs born to Large ewes may not have compensated for their dams' greater nutritional requirements compared to their smaller counterparts.

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Litter-size-dependent intrauterine growth restriction in sheep

Cited by 73 publications

References 144 publications

Placental vascularity and growth factor expression in singleton, twin, and triplet pregnancies in the sheep

Placental vascularity and growth factor expression in singleton, twin, and triplet pregnancies in the sheep

Amino Acids and Conceptus Development During the Peri-Implantation Period of Pregnancy

The effect of ewe size and nutritional regimen beginning in early pregnancy on ewe and lamb performance to weaning

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