Data/hora: 23/09/2024 03:22:06

Biblioteca(s): 	Embrapa Caprinos e Ovinos.	
Data corrente: 	22/11/2002	
Data da última atualização: 	22/11/2002	
Autoria: 	WALLACE, J. M.; BOURKE, D. A.; AITKEN, R. P.; CRUICKSHANK, M. A.	
Título: 	Switching maternal dietary intake at the end of the first trimester has profound effects on placental development and fetal growth in adolescent ewes carrying singleton fetuses.	
Ano de publicação: 	1999	
Fonte/Imprenta: 	Biology of Reproduction and Fertility, v. 61, n. 1, p. 101-110, 1999.	
Idioma: 	Inglês	
Conteúdo: 	The aim was to investigate whether placental growth and hence pregnancy outcome could be altered by switching adolescent dams from a high to a moderate nutrient intake, and vice-versa, at lhe end of lhe first trimester. Embryos recovered from adult ewes inseminated by a single sire were transferred in singleton to peripubertal adolescents. After transfer, adolescent ewes were offered a high (H, n = 33) or moderate (M, n = 32) level of a diet calculated to promote rapid or moderate maternal growth rates, respectively. At Day 50 of gestation, half lhe ewes had their dietary intakes switched, yielding 4 treatment groups: HH, MM, HM, and MH. A subset of ewes were killed at Day 104 of gestation to determine maternal body composition in relation to growth of lhe products of conception. Maternal body composition measurements revealed that lhe higher live weight . in the high-intake dams was predominantly due to an increase in body fat deposition, with a less pronounced increase in body protein. At Day 104, HH and MH groups (high intake during second trimester) compared with MM and HM groups (moderate intake during second trimester) had a lower (p < 0.002) total fetal cotyledon weight; but fetal weight, conformation, and individual organ weights were not significantly influenced by maternal dietary intake. In ewes delivering live young at term, a high plane of nutrition from lhe end of lhe first trimester (HH and MH groups) compared with moderate levels (MM and HM groups) was associated with a reduction in gestation length (p < 0.009), total placental weight (p < 0.002), total fetal cotyledon weight (p < 0.001), and mean fetal cotyledon weight per placenta (p < 0.001). Fetal cotyledon number was dependent on maternal dietary intake during lhe first trimester only and was lower (p < 0.007) in HH and HM ewes compared to MM and MH ewes. The inhibition of fetal cotyledon growth in HH and MH groups was associated with a major decrease (p < 0.001) in lamb birth weight at term relative to lhe MM and HM groups. Thus, reducing maternal dietary intake from a high to a moderate level at lhe end of lhe first trimester stimulates placental growth and enhances pregnancy outcome, and increasing maternal dietary intake at this time point has a deleterious effect on placental development and fetal growth. 

Palavras-Chave: 	Desenvolvimento embrionário; Dieta alimentar.	
Thesagro: 	Consumo; Crescimento; Ovino; Reprodução Animal.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Caprinos e Ovinos (CNPC)	
Exemplares: 	CNPC - (15140-1) - ADC - AP - -- -  -  - v.61, n.1 - DIS