Type

Journal Article

Authors

Patrick Lonergan
Maurice P Boland
Pat Duffy
Fabian Ward
Dimitrios Rizos

Subjects

Veterinary

Topics
cell survival male gonadotropin releasing hormone cells cultured blastocyst cytology embryonic and fetal development fertilization in vitro drug effects sheep physiology pharmacology animals pregnancy female embryo transfer oocytes cattle cryopreservation

Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: implications for blastocyst yield and blastocyst quality. (2002)

Abstract The aim of this study is to examine the effect of bovine oocyte maturation, fertilization or culture in vivo or in vitro on the proportion of oocytes reaching the blastocyst stage, and on blastocyst quality as measured by survival following vitrification. In Experiment 1, 4 groups of oocytes were used: (1) immature oocytes from 2-6 mm follicles; (2) immature oocytes from > 6 mm follicles; (3) immature oocytes recovered in vivo just before the LH surge; and (4) in vivo matured oocytes. Significantly more blastocysts developed from oocytes matured in vivo than those recovered just before the LH surge or than oocytes from 2-6 mm follicles. Results from > 6 mm follicles were intermediate. All blastocysts had low survival following vitrification. In Experiment 2, in vivo matured oocytes were either (1) fertilized in vitro or (2) fertilized in vivo by artificial insemination and the resulting presumptive zygotes recovered on day 1. Both groups were then cultured in vitro. In vivo fertilized oocytes had a significantly higher blastocyst yield than those fertilized in vitro. Blastocyst quality was similar between the groups. Both groups had low survival following vitrification. In Experiment 3a, presumptive zygotes produced by in vitro maturation (IVM)/fertilization (IVF) were cultured either in vitro in synthetic oviduct fluid, or in vivo in the ewe oviduct. In Experiment 3b, in vivo matured/in vivo fertilized zygotes were either surgically recovered on day 1 and cultured in vitro in synthetic oviduct fluid, or were nonsurgically recovered on day 7. There was no difference in blastocyst yields between groups of zygotes originating from the same source (in vivo or in vitro fertilization) irrespective of whether culture took place in vivo or in vitro. However, there was a dramatic effect on blastocyst quality with those blastocysts produced following in vivo culture surviving vitrification at significantly higher rates than their in vitro cultured counterparts. Collectively, these results indicate that the intrinsic quality of the oocyte is the main factor affecting blastocyst yields, while the conditions of embryo culture have a crucial role in determining blastocyst quality.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

Patrick Lonergan, Maurice P Boland, Pat Duffy, Fabian Ward, Dimitrios Rizos

Experts in our system

1
P. Lonergan
University College Dublin
Total Publications: 190
 
2
M P Boland
University College Dublin
Total Publications: 103
 
3
P. Duffy
University College Dublin
Total Publications: 42
 
4
D Rizos
University College Dublin
Total Publications: 42