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Animals : an open access journal from MDPI2025; 15(6); 832; doi: 10.3390/ani15060832

The Influence of Aspiration Pressure, Follicle Flushing Method and Needle Rotation During Single-Operator OPU Technique on Oocyte Recovery and Embryo Production in the Mare.

Abstract: The objective of this study was to determine the effect of two aspiration pressures (75 vs. 150 mmHg), the follicle flushing method (injection pump controlled by a foot pedal vs. a plastic syringe) and the twisting of the OPU needle on oocyte recovery and in vitro embryo production. OPU data from a total of 104 warmblood sport mares belonging to a commercial OPU-ICSI program were collected as part of a prospective study split into three experiments. Each mare was used only once for OPU. In Experiment 1, the mares' follicles were aspirated using either a high aspiration pressure (flow rate of 1.33 mL/s; = 18) or low aspiration pressure (0.75 mL/s; = 18); in Experiment 2, follicles were flushed using either a manual method (plastic syringe, = 18) or an automatic method (injection pump controlled by a foot pedal, = 18); and in Experiment 3, the follicles were aspirated by scraping the follicle wall with needle rotation (needle twisting, = 16) or without needle rotation (control, = 16). In all the experiments, the same OPU operator and technician searching oocytes were used, and the allocation of each mare to the different treatment groups was randomized. The overall mean oocyte recovery rate of the study was 54.2 ± 17.1%, and the mean number of embryos per OPU-ICSI session was 1.9 ± 1.6. The oocyte recovery rate was not influenced by any of the parameters investigated ( > 0.05). However, high aspiration pressure (150 mmHg) tended to yield oocytes with lower maturation (51.6%; = 0.09) and blastocyst rates (20.6%; = 0.08) following IVM and ICSI, respectively, compared with the low aspiration group (64.4% MII rate and 31.4% blastocyst rate). In conclusion, increasing aspiration pressure does not increase oocyte recovery. Furthermore, when a single operator performs the OPU (holding the ovary and handling the needle simultaneously), needle rotation to scrape the follicle wall does not improve oocyte recovery.
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Publication Date: 2025-03-14 PubMed ID: 40150362PubMed Central: PMC11939359DOI: 10.3390/ani15060832Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research tested different methods of oocyte recovery and embryo production in sport mares to determine which were most effective. The specific technique variables examined were aspiration pressure, follicle flushing methods, and needle rotation during OPU technique. In general, the results found that neither increasing aspiration pressure nor using needle rotation enhanced oocyte recovery rates.

Objective and Methodology of the Study

  • The goal of this research was to evaluate the impacts of alterations in certain operational variables on oocyte recovery and in vitro embryo production. The variables scrutinized were aspiration pressure (two levels: 75 and 150 mmHg), method of follicle flushing (via foot pedal-controlled injection pump or plastic syringe) and twisting of the OPU needle.
  • The data was gathered from 104 warmblood sport mares each only used once for oocyte pick-up (OPU). It was a prospective study broken down into three parts—each testing a different variable.
  • All experiments were conducted by the same operator and oocyte locating technician to eliminate possible inter-operator variation.

Experiments and Findings

  • In the first experiment, follicles were aspirated using high and low aspiration pressures, recorded at 1.33 mL/s and 0.75 mL/s, respectively. The second experiment compared follicle flushing methods—with a manual technique involving a plastic syringe and an automatic technique using a foot pedal-controlled injection pump. In the third experiment, some follicles were aspirated using an OPU needle rotated to scrape the follicle wall and in others, no needle rotation was applied.
  • Despite changes in these operational variations, the overall mean oocyte recovery rate remained fairly steady at around 54.2%.
  • However, experiments showed that employing a high aspiration pressure of 150 mmHg resulted in lower oocyte maturation and blastocyst rates compared to the low aspiration group. This suggests an optimal pressure level for highest oocyte maturation and blastocyst success.
  • Additional findings illustrated that using a scraping motion with the OPU needle did not improve oocyte recovery rates.

Conclusion

  • The findings concluded two main points—increasing aspiration pressure does not boost oocyte recovery and using a rotating OPU needle to scrape the follicle wall does not improve oocyte recovery rates.
  • Given these outcomes, it was deduced that the most effective approach to oocyte recovery and in vitro embryo production should maintain a low aspiration pressure and not necessarily involve the scraping technique.

Cite This Article

APA
Cuervo-Arango J, Sala-Ayala L, Márquez-Moya A, Martínez-Boví R. (2025). The Influence of Aspiration Pressure, Follicle Flushing Method and Needle Rotation During Single-Operator OPU Technique on Oocyte Recovery and Embryo Production in the Mare. Animals (Basel), 15(6), 832. https://doi.org/10.3390/ani15060832

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 6
PII: 832

Researcher Affiliations

Cuervo-Arango, Juan
  • Equine Fertility Group, Faculty of Veterinary Medicine, Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Alfara del Patriarca, Valencia, Spain.
Sala-Ayala, Laura
  • Equine Fertility Group, Faculty of Veterinary Medicine, Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Alfara del Patriarca, Valencia, Spain.
Márquez-Moya, Adrián
  • Equine Fertility Group, Faculty of Veterinary Medicine, Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Alfara del Patriarca, Valencia, Spain.
Martínez-Boví, Rebeca
  • Equine Fertility Group, Faculty of Veterinary Medicine, Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Alfara del Patriarca, Valencia, Spain.

Conflict of Interest Statement

The authors declare no conflicts of interest.

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Citations

This article has been cited 1 times.
  1. Márquez-Moya A, Carreras-Vico N, Sala-Ayala L, Martínez-Boví R, Cuervo-Arango J. Comparative Evaluation of Follicular Flushing Frequency and Scraping Time During Ovum Pick-Up in Mares: Effects on Oocyte Recovery Rate and Technical Considerations. Reprod Domest Anim 2026 Feb;61(2):e70183.
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