The effect of serum on in vitro maturation, in vitro fertilization and steroidogenesis of bovine oocytes co-cultured with granulosa cells.
The influence of fetal calf serum alone (FCS) or associated with proestrous (FCS+PCS), estrous (FCS+ECS) or metaestrous (FCS+MCS) cow serum added to the culture medium and of the steroids produced by co-cultured granulosa cells were evaluated in terms of the in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. Supplementation of the medium with FCS+ECS and FCS+MCS resulted in higher proportions of oocytes that reached metaphase II (96.0% and 93.3%, respectively) and in higher proportions of embryos that reached the four- and eight-cell/morula stages (51.9% and 65.6%, respectively), whereas the supplementation with FCS and FCS+PCS resulted in only 79.2% and 67.5%, respectively, of matured oocytes and 26.7% and 34.3%, respectively, of cleaved embryos. These findings show that the best IVM and IVF were obtained at lower concentrations of estradiol produced by co-cultured granulosa cells (supplementation with FCS+ECS: 10.3 ng/ml and FCS+MCS: 2.1 ng/ml), whereas the worst results in IVM and IVF occurred at higher concentrations of estradiol that were obtained with FCS (33.1 ng/ml) and FCS+PCS (19.9 ng/ml) supplementation. These data suggest an inhibitory effect of estradiol on resumption of oocyte meiosis in vitro.
Mingoti
G Z
GZ
Departamento de Apoio, Produção e Saúde Animal, Universidade Estadual Paulista, Araçatuba, SP, Brasil.
Garcia
J M
JM
Rosa-e-Silva
A A
AA
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003470:Culture Media; D005314:Embryonic and Fetal Development; D004971:Estrus / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D005312:Fetal Blood / Q000502:physiology*; D006107:Granulosa Cells / Q000502:physiology*; D009865:Oocytes / Q000254:growth & development; D013256:Steroids / Q000096:biosynthesis*
D003470:Culture Media; D013256:Steroids