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RESEARCH ARTICLE

Directional freezing of spermatozoa and embryos

Amir Arav A C and Joseph Saragusty B
+ Author Affiliations
- Author Affiliations

A Shlomzion Hamalca 59, Tel Aviv 62266, Israel.

B Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany.

C Corresponding author. Email: arav@agri.huji.ac.il

Reproduction, Fertility and Development 26(1) 83-90 https://doi.org/10.1071/RD13295
Published: 5 December 2013

Abstract

Directional freezing is based on a simple thermodynamic principle whereby the sample is moved through a predetermined temperature gradient at a velocity that determines the cooling rate. Directional freezing permits a precise and uniform cooling rate in small- and large-volume samples. It avoids supercooling and reduces mechanical damage caused by crystallisation. Directional solidification was used to date for slow and rapid freezing, as well as for vitrification of oocytes and embryos by means of the minimum drop size technique: small drops are placed on a microscope slide that is moved at high velocity from the hot base to the cold base. Sperm samples from a wide range of domestic and wild animals were successfully cryopreserved using the directional freezing method. The bovine sexed semen industry may benefit from the increased survival of spermatozoa after directional freezing.

Additional keywords: solidification, vitrification.


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