JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 84 No. 8 1800-1804
© 2001 by American Dairy Science Association ®
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by De Wit, A. A. C.
Right arrow Articles by Kruip, T. A. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by De Wit, A. A. C.
Right arrow Articles by Kruip, T. A. M.

Effect of Urea During In Vitro Maturation on Nuclear Maturation and Embryo Development of Bovine Cumulus-Oocyte-Complexes

A. A. C. De Wit 1, M. L. F. Cesar 1, and T. A. M. Kruip 1

1 ID-Lelystad, P.O. Box 65, 8200 AB Lelystad, The Netherlands

High concentrations of urea in reproductive tract fluids are detrimental to bovine reproduction. Therefore, in experiment 1, the effect of 6 mM urea on nuclear maturation of cumulus-oocyte-complexes (COC) collected from abattoir ovaries was studied. After 4, 8, 12, 16, 20, and 24 h of in vitro maturation, the nuclear stages of samples of the COC were determined. During the first 8 h of maturation, germinal vesicle breakdown and chromosome condensation, resulting in the metaphase I stage, occurred at higher rates in the presence of urea. Segregation of the chromatids and extrusion of the polar body seemed to be impaired in the presence of urea, resulting in a higher percentage of oocytes arrested in metaphase I or telophase, and a lower percentage of oocytes in metaphase II after 24 h of maturation. Overall, nuclear progression of COC matured in the presence of urea differed from COC matured in control medium.

In experiment 2, COC were matured for 24 h either in the presence or absence of 6 mM urea followed by in vitro fertilization and culture. After fertilization, a sample of the COC was fixed and stained to determine the fertilization rate. The cleavage rate was determined 3 d after start of maturation, and the stage of embryonic development was recorded 7 and 9 d after start of maturation. Based on cultured oocytes, urea in the maturation medium decreased the subsequent percentage of fertilization, cleavage, and development on d 7 and 9 (43.2, 56.1, 14.8, and 18.2%, respectively for urea vs. 64.1, 68.8, 22.4, and 23.9%, respectively for the control group). Embryonic development as a percentage of cleaved oocytes was not significantly affected by urea. Therefore, negative effects of urea were evident primarily during oocyte maturation and fertilization.

Key Words: bovine • urea • oocyte maturation • in vitro embryo production

Submitted on October 16, 2000
Accepted on April 20, 2001




This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
O. M. Ocon and P. J. Hansen
Disruption of Bovine Oocytes and Preimplantation Embryos by Urea and Acidic pH
J Dairy Sci, April 1, 2003; 86(4): 1194 - 1200.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Reprod.Home page
D.A. Kenny, P.G. Humpherson, H.J. Leese, D.G. Morris, A.D. Tomos, M.G. Diskin, and J.M. Sreenan
Effect of Elevated Systemic Concentrations of Ammonia and Urea on the Metabolite and Ionic Composition of Oviductal Fluid in Cattle
Biol Reprod, June 1, 2002; 66(6): 1797 - 1804.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2001 by the American Dairy Science Association ®.