The effect of age and length of gonadotropin stimulation on the in vitro embryo development of Holstein calf oocytes.

Autor: Currin L; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Michalovic L; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Bellefleur AM; L'Alliance Boviteq, Saint-Hyacinthe, Quebec, Canada., Gutierrez K; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Glanzner W; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Schuermann Y; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Bohrer RC; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Dicks N; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., da Rosa PR; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., De Cesaro MP; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Lopez R; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Grand FX; L'Alliance Boviteq, Saint-Hyacinthe, Quebec, Canada., Vigneault C; L'Alliance Boviteq, Saint-Hyacinthe, Quebec, Canada., Blondin P; L'Alliance Boviteq, Saint-Hyacinthe, Quebec, Canada., Gourdon J; Comparative Medicine and Animal Resources Centre, McGill University, Montreal, Quebec, Canada., Baldassarre H; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada., Bordignon V; Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada. Electronic address: vilceu.bordignon@mcgill.ca.
Jazyk: angličtina
Zdroj: Theriogenology [Theriogenology] 2017 Dec; Vol. 104, pp. 87-93. Date of Electronic Publication: 2017 Aug 10.
DOI: 10.1016/j.theriogenology.2017.08.011
Abstrakt: The use of oocytes recovered from prepubertal donors for in vitro embryo production has great potential for accelerating the rate of genetic gain in the dairy industry. However, these oocytes are known to be less developmentally competent than those from adult donors. In this study, we investigated the effect of age and gonadotropin stimulation in Holstein heifers subjected to oocyte collection every two weeks between 2 and 6 months of age. In order to assess the effect of gonadotropin stimulation, animals were subjected to one of three treatments, namely Short (ST; 36-42 h), Long (LT; ≥72 h) and No Treatment (NT) prior to laparoscopic ovum pick-up (LOPU). Our results show that the LT significantly improved the proportion of large follicles (>5 mm diameter) present in the ovary (LT 34.0% vs. ST 11.2% vs. NT 2.4%, P < 0.05), as well as the percentage of good-quality cumulus oocyte complexes (COCs) recovered (LT 95.3 ± 18% vs. ST 85.4 ± 22% vs. NT 82.2 ± 14%, P < 0.05) and blastocyst rate (LT 36.7 ± 26% vs. ST 18.3 ± 15% vs. NT 16.7 ± 9%, P < 0.05). Recovery rate was affected by treatment (LT 70.4 ± 25 vs. ST 85.4 ± 29 vs. NT 72.7 ± 23, P < 0.05). To assess the impact of age, data was grouped into <100 days (A), 100-130 days (B) and >130 days (C) of age at LOPU. We found that as animals got older, although the average number of COCs per donor per LOPU declined (A: 17.5 ± 11 vs. B: 14.7 ± 7 vs. C: 11.9 ± 8), the blastocyst rate increased (A: 12.8 ± 20% vs. B: 17.1 ± 21% vs. C: 21.8 ± 25%, P < 0.05). We also evaluated the incidence of polyspermy and confirmed it is a critical limitation for IVF in calf oocytes. The incidence of polyspermy was unaffected by gonadotropin treatment, but significantly decreased with age. The capacity for full development to term of in vitro produced embryos from calf oocytes was tested by embryo transfer into 21 synchronized adult recipients, which resulted in 13 pregnancies (62%), full development to term and healthy calves born. Finally, the study allowed evaluating the safety of the procedure since, on average, each animal was subjected to 8 LOPU procedures over a period of 4 months. Our results showed that the procedure is safe (no incidents during laparoscopy), and was not harmful for the reproductive future of the animals, as those that were bred became pregnant after reaching sexual maturity.
(Copyright © 2017 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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