Morphology and morphometry of in vivo- and in vitro-produced bovine concepti from early pregnancy to term and association with high birth weights.
Theriogenology
; 58(5): 973-94, 2002 Sep.
Article
em En
| MEDLINE
| ID: mdl-12212896
ABSTRACT
This study was designed to characterize conceptus development based on pre- and postnatal measurements of in vivo- and in vitro-derived bovine pregnancies. In vivo-produced embryos were obtained after superovulation, whereas in vitro-produced embryos were derived from established procedures for bovine IVM, IVF and IVC. Blastocysts were transferred to recipients to obtain pregnancies of single (in vivo/singleton or in vitro/singleton groups) or twin fetuses (in vitro/twins group). Ultrasonographic examinations were performed weekly, from Day 30 of gestation through term. Videotaped images were digitized, and still-frames were used for the measurement of conceptus traits. Calves and fetal membranes (FM) were examined and measured upon delivery. In vitro-produced fetuses were smaller than in vivo controls (P < 0.05) during early pregnancy (Day 37 to Day 58), but in vitro/singletons presented significantly higher weights at birth than in vivo/control and in vitro/twin calves (P < 0.05). From late first trimester of pregnancy (Day 72 to Day 93), placentomes surrounding in vitro-derived singleton fetuses were longer and thinner than controls (P < 0.05). At term, the presence of giant cotyledons in the fetal membranes in the in vitro group was associated with a larger cotyledonary surface area in the fetal horn (P < 0.05). The biphasic growth pattern seen in in vitro-produced pregnancies was characterized by conceptus growth retardation during early pregnancy, followed by changes in the development of the placental tissue. Resulting high birth weights may be a consequence of aberrant placental development due to the disruption of the placental restraint on fetal growth toward the end of pregnancy.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peso ao Nascer
/
Bovinos
/
Fertilização in vitro
/
Idade Gestacional
/
Desenvolvimento Embrionário e Fetal
Tipo de estudo:
Diagnostic_studies
/
Risk_factors_studies
Limite:
Animals
/
Pregnancy
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article