Follicular growth, endocrine response and embryo yields in sheep superovulated with FSH after pretreatment with a single short-acting dose of GnRH antagonist
The objective of this study was to characterize follicular development, onset of oestrus and preovulatory LH surge, and in vivo embryo yields of sheep superovulated after treatment with a single dose of 1.5 mg of GnRH antagonist (GnRHa). At first FSH dose, ewes treated with GnRH antagonist (n = 12) showed a higher number of gonadotrophin-responsive follicles, 2-3 mm, than control ewes (n = 9, 13.5 ± 3.8 versus 5.3 ± 0.3, P < 0.05). Administration of FSH increased the number of ≥4 mm follicles at sponge removal in both groups (19.3 ± 3.8, P < 0.0005 for treated ewes and 12.7 ± 5.4, P < 0.01 for controls). Thereafter, a 25% of the GnRHa-treated sheep did not show oestrous behaviour whilst none control sheep failed (P = 0.06). The preovulatory LH surge was detected in an 88.9% of control ewes and 66.7% of GnRHa-treated sheep. A 77.8% of control females showed ovulation with a mean of 9.6 ± 0.9 CL and 3.3 ± 0.7 viable embryos, while ewes treated with GnRHa and showing an LH surge exhibited a bimodal distribution of response; 50% showed no ovulatory response and 50% superovulated with a mean of 12.2 ± 1.1 CL and 7.3 ± 1.1 viable embryos. In conclusion, a single dose of GnRHa enhances the number of gonadotrophin-dependent follicles able to grow to preovulatory sizes in response to an FSH supply. However, LH secretion may be altered in some females, which can affect the preovulatory LH surge and/or can weak the terminal maturation of ovulatory follicles. © 2005 Elsevier Inc. All rights reserved.
Main Authors: | Lopez-Alonso, C., Encinas, T., Veiga-Lopez, A., Garcia-Garcia, R. M., Cocero Oviedo, María Jesús, Ros, J. M., McNeilly, A. S., González De Bulnes, Antonio |
---|---|
Format: | artículo biblioteca |
Language: | English |
Published: |
Elsevier
2005
|
Subjects: | Follicle, GnRH analogues, Sheep, Superovulation, |
Online Access: | http://hdl.handle.net/20.500.12792/2449 http://hdl.handle.net/10261/291861 |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Similar Items
-
Restoration of endocrine and ovarian function after stopping GnRH antagonist treatment in goats
by: González De Bulnes, Antonio, et al.
Published: (2005) -
Effect of GnRH antagonists treatment on gonadotrophin secretion, follicular development and inhibin A secretion in goats
by: González De Bulnes, Antonio, et al.
Published: (2004) -
Ovarian response in sheep superovulated after pretreatment with growth hormone and GnRH antagonists is weakened by failures in oocyte maturation
by: Gonzalez-Añover, P., et al.
Published: (2004) -
Administration of single short-acting doses of GnRH antagonist modifies pituitary and follicular function in sheep
by: Lopez-Alonso, C., et al.
Published: (2005) -
Use of GnRH for Synchronization of the Follicular Wave in Assisted Reproductive Technologies in Sheep: A Preliminary Study
by: Año-Perello, Aina, et al.
Published: (2020-07-16)