Treatment with recombinant equine follicle stimulating hormone (reFSH) followed by recombinant equine luteinizing hormone (reLH) increases embryo recovery in superovulated mares.
Abstract: The dynamics of ovarian follicular development depend on a timely interaction of gonadotropins and gonadal feedback in the mare. The development and efficacy of genetically cloned recombinant equine gonadotropins (reFSH and reLH) increase follicular activity and induce ovulation, respectively, but an optimum embryo recovery regimen in superovulated mares has not been established. The objective of this study was to determine if treatment with reFSH followed by reLH would increase the embryo per ovulation ratio and the number of embryos recovered after superovulation in mares. Sixteen estrous cycling mares of light horse breeds (4-12 years) were randomly assigned to one of two groups: Group 1; reFSH (0.65mg)/PBS (n=8) and Group 2; reFSH (0.65mg)/reLH (1.5mg) (n=8). On the day of a 22-25mm follicle post-ovulation mares were injected IV twice daily with reFSH for 3 days (PGF(2α) given IM on the second day of treatment) and once per day thereafter until a follicle or cohort of follicles reached 29mm after which either PBS or reLH was added and both groups injected IV twice daily until the presence of a 32mm follicles, when reFSH was discontinued. Thereafter, mares were injected three times daily IV with only PBS or reLH until a majority of follicles reached 35-38mm when treatment was discontinued. Mares were given hCG IV (2500IU) to induce ovulation and bred. Embryo recovery was performed on day 8 day post-treatment ovulation. Daily jugular blood samples were collected from the time of first ovulation until 8 days post-treatment ovulation. Blood samples were analyzed for LH, FSH, estradiol, progesterone and inhibin by validated RIA. Duration of treatment to a ≥35mm follicle(s) and number of ovulatory size follicles were similar between reFSH/reLH and reFSH/PBS treated mares. The number of ovulations was greater (P<0.01) in the reFSH/reLH group, while the number of anovulatory follicles was less (P<0.05) compared to the reFSH/PBS group. Number of total embryos recovered were greater in reFSH/reLH mares than in the reFSH/PBS mares (P≤0.01). The embryo per ovulation ratio tended to be greater (P=0.07) in the reFSH/reLH mares. Circulating concentrations of estradiol, inhibin, LH and progesterone were not statistically different between groups. Plasma concentrations of FSH were less (P<0.01) in the reFSH/reLH treated mares on days 0, 1, 4, 6, 7 and 8 post-treatment ovulation. In summary, reFSH with the addition of reLH, which is critical for final follicular and oocyte maturation, was effective in increasing the number of ovulations and embryos recovered, as well as reduce the number of anovulatory follicles, making this a more viable option than treatment with reFSH alone. Further evaluation is needed to determine the dose and regimen of reFSH/reLH to significantly increase the embryo per ovulation ratio.
Copyright © 2011 Copyright © 2011 Elsevier B.V. All rights reserved.
Publication Date: 2011-09-17 PubMed ID: 22005252DOI: 10.1016/j.anireprosci.2011.09.002Google Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
- Research Support
- Non-U.S. Gov't
Summary
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This study determined that treatment using a combination of recombinant equine follicle stimulating hormone (reFSH) and recombinant equine luteinizing hormone (reLH) effectively increases the number of embryos that can be recovered from superovulated mares, compared to a treatment regimen that only utilizes reFSH.
Objective of the Study
- This research aimed to establish a more efficient method for optimizing embryo recovery from mares during superovulation, by testing a treatment method that incorporates both reFSH and reLH.
Method of the Study
- The experiment involved 16 light horse breed mares, aged between 4 to 12 years, which were undergoing estrous cycling. The mares were grouped into two; the first group receiving treatment with reFSH and PBS, and the second group receiving reFSH and reLH treatment.
- The mares were injected twice daily with reFSH for three days, and daily thereafter until their follicles reached a size of 29mm. PBS or reLH was then added to their regimen while reFSH treatment continued.
- Treatment was discontinued once the majority of follicles measured 35-38mm, after which the mares were given hCG to facilitate ovulation.
- Blood samples were collected from the mares daily, beginning from their first ovulation to the 8th day after post-treatment ovulation, in order to analyze hormone levels.
- On the 8th day following post-treatment ovulation, an embryo recovery procedure was carried out.
Key Findings
- Both treatment groups – reFSH/reLH and reFSH/PBS – showed similar durations of treatment to reach follicle(s) of ≥35mm, as well as numbers of ovulatory size follicles.
- However, the reFSH/reLH treatment group reported more ovulations and fewer anovulatory follicles compared to the reFSH/PBS group (P<0.01 and P<0.05, respectively).
- The reFSH/reLH treatment group also had more total embryos recovered compared to the reFSH/PBS group (P≤0.01).
- There was a trend suggesting a higher embryo per ovulation ratio in the group treated with both reFSH and reLH (P=0.07).
- Differences in concentrations of specific hormones (estradiol, inhibin, LH, and progesterone) in both groups were not statistically significant.
- Lower plasma concentrations of FSH were observed in the reFSH/reLH-treated mares on days 0,1,4,6,7, and 8 following post-treatment ovulation.
Conclusion
- The study concluded that the addition of reLH to a reFSH treatment regimen is crucial for final follicular and oocyte maturation. This protocol increased the number of ovulations, reduced anovulatory follicles, and thus improved the total number of embryos recovered compared to using reFSH alone.
- The authors suggest further investigation into the dosage and regimen of reFSH/reLH treatment for significantly increasing the embryo per ovulation ratio.
Cite This Article
APA
Meyers-Brown G, Bidstrup LA, Famula TR, Colgin M, Roser JF.
(2011).
Treatment with recombinant equine follicle stimulating hormone (reFSH) followed by recombinant equine luteinizing hormone (reLH) increases embryo recovery in superovulated mares.
Anim Reprod Sci, 128(1-4), 52-59.
https://doi.org/10.1016/j.anireprosci.2011.09.002 Publication
Researcher Affiliations
- Department of Animal Science, University of California-Davis, CA 95616, USA.
MeSH Terms
- Animals
- Embryo Transfer / veterinary
- Female
- Follicle Stimulating Hormone / pharmacology
- Horses / embryology
- Horses / physiology
- Luteinizing Hormone / pharmacology
- Ovarian Follicle / drug effects
- Ovarian Follicle / physiology
- Recombinant Proteins
- Time Factors
Citations
This article has been cited 2 times.- Gifre L, Arís A, Bach À, Garcia-Fruitós E. Trends in recombinant protein use in animal production. Microb Cell Fact 2017 Mar 4;16(1):40.
- Iqbal K, Chitwood JL, Meyers-Brown GA, Roser JF, Ross PJ. RNA-seq transcriptome profiling of equine inner cell mass and trophectoderm. Biol Reprod 2014 Mar;90(3):61.
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