[1] 张帆,崔凯,王杰,等.妊娠后期饲粮营养水平对母羊和胚胎发育的影响[J].畜牧兽医学报,2016,48(3):474-482. ZHANG F,CUI K,WANG J,et al.Effects of dietary nutrient levels on the development of late pregnant ewes and fetal[J].Chinese Journal of Animal and Veterinary Sciences,2017,48(3):474-482.(in Chinese)
[2] XUE Y F,GUO C Z,HU F,et al.Maternal undernutrition induces fetal hepatic lipid metabolism disorder and affects the development of fetal liver in a sheep model[J].The FASEB Journal,2019,33(9):9990-10004.

[3] MEHER A,SUNDRANI D,JOSHI S.Maternal nutrition influences angiogenesis in the placenta through peroxisome proliferator activated receptors:a novel hypothesis[J].Molecular Reproduction & Development,2015,82(10):726-734.

[4] MÉTHOT H,GIRARD C L,MATTE J J,et al.Effects of dietary supplements of folic acid on reproductive performance in ewes[J].Canadian Journal of Animal Science,2008,88(3):489-497.

[5] 盘瑶晖.叶酸在动物生产中的应用[J].饲料与畜牧,2015(11):45-47. PAN Y H.Application of folates in animal production[J].Feed and Animal Husbandry,2015(11):45-47.(in Chinese)
[6] GIRARD C L,CASTONGUAY F,FAHMY M H,et al.Serum and milk folates during the first two gestations and lactations in Romanov,Finnsheep,and Suffolk ewes[J].Journal of Animal Science,1996,74(7):1711-1715.

[7] 李丹,吴坤.叶酸和同型半胱氨酸对血管病的影响及其机制[J].疾病控制杂志,2006,10(3):299-302. LI D,WU K.Effect and mechanism of folic acid and Hcy on vascular diseases[J].Chinese Journal of Disease Control,2006,10(3):299-302.(in Chinese)
[8] PEREIRA R D,DE LONG N E,WANG R C,et al.Angiogenesis in the placenta:the role of reactive oxygen species signaling[J].Biomed Research International,2015,2015:814543.
[9] REYNOLDS L P,CATON J S,REDMER D A,et al.Evidence for altered placental blood flow and vascularity in compromised pregnancies[J].The Journal of Physiology,2006,572(1):51-58.

[10] REYNOLDS L P,BOROWICZ P P,VONNAHME K A,et al.Placental angiogenesis in sheep models of compromised pregnancy[J].The Journal of Physiology,2005,565(1):43-58.

[11] PARRAGUEZ V H,ATLAGICH M A,URQUIETA B,et al.Expression of vascular endothelial growth factor and endothelial nitric oxide synthase is increased in the placenta of sheep at high altitude in the Andes[J].Canadian Journal of Veterinary Research,2010,74(3):193-199.
[12] MEHTA V.The effects of
VEGF overexpression on the utero-placental circulation[D].Ph.D.Thesis.London:University College London,2011.
[13] WANG B,LI H Q,LI Z,et al.Maternal folic acid supplementation modulates the growth performance,muscle development and immunity of
Hu sheep offspring of different litter size[J].The Journal of Nutritional Biochemistry,2019,70:194-201.
[14] LI H Q,WANG B,LI Z,et al.Effects of rumen-protected folic acid addition in maternal and post-weaning diets on growth performance,total tract digestibility,ruminal fermentation and blood metabolites in lambs[J].Animal Feed Science and Technology,2020,260:114364.
[15] 李贞.母羊妊娠期日粮添加叶酸对新生羔羊小肠发育的影响[D].硕士学位论文.北京:中国农业大学,2019. LI Z.Effects of dietary folic acid supplementation in pregnant ewes on small intestinal development of newborn lambs[D].Master's Thesis.Beijing:China Agricultural University,2019.(in Chinese)
[16] REYNOLDS L P,REDMER D A.Angiogenesis in the placenta[J].Biology of Reproduction,2001,64(4):1033-1040.

[17] ZABIHI S,ERIKSSON U J,WENTZEL P.Folic acid supplementation affects ROS scavenging enzymes,enhances Vegf-A,and diminishes apoptotic state in yolk sacs of embryos of diabetic rats[J].Reproductive Toxicology,2007,23(4):486-498.

[18] 徐业芬.Smad信号转导通路相关基因表达与湖羊高繁殖力关系的研究[D].博士学位论文.南京:南京农业大学,2010:88-89. XU Y F.Gene expressions related to Smad signaling molecule and its relationship with fecundity in
Hu sheep[D].Ph.D.Thesis.Nanjing:Nanjing Agricultural University,2010:88-89.(in Chinese)
[19] HOLIFIELD J S,ARLEN A M,RUNYAN R B,et al.TGF-β
1,-β
2 and -β
3 cooperate to facilitate tubulogenesis in the explanted quail heart[J].Journal of Vascular Research,2004,41(6):491-498.

[20] LEBRIN F,DECKERS M,BERTOLINO P,et al.TGF-β receptor function in the endothelium[J].Cardiovascular Research,2005,65(3):599-608.

[21] MERWIN J R,ROBERTS A,KONDAIAH P,et al.Vascular cell responses to TGF-β3 mimic those of TGF-β
1 in vitro[J].Growth Factors,1991,5(2):149-158.

[22] ZOGRAFOU A,TSIGRIS C,PAPADOPOULOS O,et al.Improvement of skin-graft survival after autologous transplantation of adipose-derived stem cells in rats[J].Journal of Plastic,Reconstructive & Aesthetic Surgery,2011,64(12):1647-1656.

[23] HAGEN A S E,ORBUS R J,WILKENING R B,et al.Placental expression of angiopoietin-1,angiopoietin-2 and tie-2 during placental development in an ovine model of placental insufficiency-fetal growth restriction[J].Pediatric Research,2005,58(6):1228-1232.

[24] 杨柳,徐农.抗血管生成靶向治疗的作用机制[J].实用肿瘤杂志,2013,28(2):109-113. YANG L,XU N.The mechanism of anti-angiogenesis targeted therapy[J].Journal of Practical Oncology,2013,28(2):109-113.(in Chinese)
[25] 史萌萌,奚胜艳,王彦晖,等.桃红四物汤对肝纤维化小鼠病理性血管生成相关因子
VEGF、
KDR与
Flt-1表达的影响[J].中华中医药杂志,2016,31(2):487-491. SHI M M,XI S Y,WANG Y H,et al.Effects of
Taohong Siwu decoction on the expression of pathological angiogenesis correlation factors including
VEGF,
KDR and
Flt-1 in hepatic fibrosis mice[J]. China Journal of Traditional Chinese Medicine and Pharmacy, 2016,31(2):487-491.(in Chinese)
[26] GILLE H,KOWALSKI J,LI B,et al.Analysis of biological effects and signaling properties of Flt-1(VEGFR-1) and KDR (VEGFR-2):a reassessment using novel receptor-specific vascular endothelial growth factor mutants[J].Journal of Biological Chemistry,2001,276(5):3222-3230.

[27] LI Y Q,XIA Y,JIN B.Effect of Anti-KDR antibody on the proliferation of hemangioma vascular endothelial cells
in vitro[J].Journal of Huazhong University of Science and Technology,2007,27(5):551-553.

[28] QUINN K E,ASHLEY A K,REYNOLDS L P,et al.Activation of the CXCL12/CXCR4 signaling axis may drive vascularization of the ovine placenta[J].Domestic Animal Endocrinology,2014,47:11-21.
[29] 曹忻.血管内皮生长因子促进绵羊卵母细胞体外成熟机理研究[D].博士学位论文.兰州:甘肃农业大学,2008:64-65. CAO X.The mechanism of vascular endothelial growth factor on promoting ovine oocyte maturation
in vitro[D].Ph.D.Thesis.Lanzhou:Gansu Agricultural University,2008:64-65.(in Chinese)
[30] LIVAK K J,SCHMITTGEN T D.Analysis of relative gene expression data using real-time quantitative PCR and the 2
-△△Ct method[J].Methods,2001,25(4):402-408.

[31] 曲扬华.维生素E对绵羊精子发生的影响及其作用机制[D].博士学位论文.北京:中国农业大学,2018:34. QU Y H.Effects of vitamin E supplementation on ovine spermatogenesis and its regulating mechanisms[D]. Ph.D.Thesis. Beijing:China Agricultural University, 2018:34.(in Chinese)
[32] 范景胜,熊朝瑞,俄木曲者,等.山羊的胎盘性状与繁殖性能的相关分析[J].西南民族大学学报(自然科学版),2015,41(3):295-298. FAN J S,XIONG C R,EMU Q Z.Correlation analysis of placental traits and reproductive performance in goats[J].Journal of Southwest Minzu University (Natural Science Edition), 2015,41(3):295-298.(in Chinese)
[33] WILSON M E,BIENSEN N J,FORD S P.Novel insight into the control of litter size in pigs,using placental efficiency as a selection tool[J].Journal of Animal Science,1999,77(7):1654-1658.

[34] 王立贤,李光全,刘剑锋.猪胎盘效率用于选择产仔数的研究[J].畜牧兽医学报,2004,35(5):487-490. WANG L X, LI G Q, LIU J F. Study on using placental efficiency select litter size in pig[J]. Chinese Journal of Animal and Veterinary Sciences,2004,35(5):487-490.(in Chinese)
[35] DWYER C M,CALVERT S K,FARISH M,et al.Breed,litter and parity effects on placental weight and placentome number,and consequences for the neonatal behaviour of the lamb[J].Theriogenology,2005,63(4):1092-1110.

[36] OCAK S,EMSEN E,KÖYCEGIZ F,et al.Comparison of placental traits and their relation to litter size and parity weight in sheep[J].Journal of Animal Science,2009,87(10):3196-3201.

[37] BABIAK A,SCHUMM A M,WANGLER C,et al.Coordinated activation of VEGFR-1 and VEGFR-2 is a potent arteriogenic stimulus leading to enhancement of regional perfusion[J].Cardiovascular Research,2004,61(4):789-795.

[38] CHEN F,WANG T J,FENG C P,et al.Proteome differences in placenta and endometrium between normal and intrauterine growth restricted pig fetuses[J].PLoS One,2015,10(11):e0142396.