Recent developments in cryopreservation of stallion semen with special emphasis on thawing procedure using thermal hysteresis proteins.

This research study explores the process of cryopreservation of stallion semen, focusing on improving the thawing procedures using thermal hysteresis proteins (THPs) from Antarctic and Arctic fish in order to avoid damage to the sperm and increase post-thaw viability.

Background

• The practice of cooling and preserving stallion semen goes back as long as 200 years ago. However, the utilization of frozen stallion semen, even decades after the first achieved pregnancy through the method, has been minimal due to its correlation with reduced fertility.
• The research indicates that the standard procedure for successful cryopreservation of semen involves warming straws with a water bath of 75 °C. This method is widely accepted and applied to various species, including boars.

Disadvantages of Current Thawing Methods

• The current thawing process utilizing a 75 °C water bath comes with a multitude of drawbacks. One of the primary limitations is the need for precise timing – an error margin of just two seconds can lead to overheating and hence, damage to the cells.
• The procedure demands prior knowledge of the straw type due to the variations in thermal conductivity.
• The procedure requires individual straw thawing and the use of two water baths (75 °C and 38 °C), which makes application in the field challenging.
• A risk exists wherein straws may unintentionally swell and burst.

Study Purpose

• The main objective of this study is to develop a simpler thawing procedure for the successful cryopreservation of stallion semen that particularly steers clear from the use of a 75 °C water bath.

Involvement of Thermal Hysteresis Proteins (THPs)

• As part of the aimed improvement, the research explores the use of thermal hysteresis proteins (THPs) obtained from Antarctic and Arctic fish.
• The researchers examine how slow thawing can damage stallion semen and evaluate the potential of THPs to influence ice recrystallisation. They also assess the toxicity and post-thaw viability of stallion sperm following the incorporation of these cryoprotective proteins.