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Vertebrate reproductive science and technology
RESEARCH ARTICLE

Use of time-lapse imaging to evaluate morphokinetics of in vitro equine blastocyst development after oocyte holding for two days at 15°C versus room temperature before intracytoplasmic sperm injection

N. A. Martino https://orcid.org/0000-0001-6853-2757 A B G , G. Marzano C D , A. Mastrorocco A , G. M. Lacalandra E , L. Vincenti B , K. Hinrichs https://orcid.org/0000-0002-8581-3814 F * and M. E. Dell’Aquila A *
+ Author Affiliations
- Author Affiliations

A Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Str. Prov. Casamassima Km 3, 70010, Valenzano, Bari, Italy.

B Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, Italy.

C Department of Mathematics and Physics Ennio de Giorgi, University of Salento, Via per Arnesano, 73100, Lecce, Italy.

D Institute of Nanotechnology, CNR Nanotec, Via per Monteroni, 73100, Lecce, Italy.

E Department of Veterinary Medicine, University of Bari Aldo Moro, Str. Prov. Casamassima Km 3, 70010, Valenzano, Bari, Italy.

F Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 4466 TAMU, College Station, TX 77843-4466, USA.

G Corresponding author. Email: nicolaantonio.martino@unito.it

Reproduction, Fertility and Development 31(12) 1862-1873 https://doi.org/10.1071/RD19223
Submitted: 18 June 2019  Accepted: 17 October 2019   Published: 11 November 2019

Abstract

Time-lapse imaging was used to establish the morphokinetics of equine embryo development to the blastocyst stage after in vitro oocyte maturation (IVM), intracytoplasmic sperm injection (ICSI) and embryo culture, in oocytes held overnight at room temperature (22–27°C; standard conditions) before IVM. Embryos that developed to the blastocyst stage underwent precleavage cytoplasmic extrusion and cleavage to the 2-, 3- and 4-cell stages significantly earlier than did embryos that arrested in development. We then determined the rate of blastocyst formation after ICSI in oocytes held for 2 days at either 15°C or room temperature before IVM (15-2d and RT-2d treatment groups respectively). The blastocyst development rate was significantly higher in the 15-2d than in the RT-2d group (13% vs 0% respectively). The failure of blastocyst development in the RT-2d group precluded comparison of morphokinetics of blastocyst development between treatments. In any condition examined, development to the blastocyst stage was characterised by earlier cytoplasmic extrusion before cleavage, earlier cleavage to 2- and 4-cell stages and reduced duration at the 2-cell stage compared with non-competent embryos. In conclusion, this study presents morphokinetic parameters predictive of embryo development in vitro to the blastocyst stage after ICSI in the horse. We conclude that time-lapse imaging allows increased precision for evaluating effects of different treatments on equine embryo development.

Additional keywords: embryo, IVF, IVM.


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