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Barex Biochemical Products

The art of semen preservation

Progress Report 1. Stallion semen freezing extenders.


Cryopreservation of sperm cells as well as other biological material has been widely used in reproductive technologies and has resulted in millions of live births. Two principal approaches have been used: conventional (slow) freezing and vitrification. 

Slow freezing is the traditional technique and is widely being used with success, whereas vitrification is still in the developmental phase. But vitrification may become a faster alternative method of cryopreservation since vitrification can be done with simple equipment and little training of personnel, as opposed to slow freezing which requires a large investment in equipment and extensive training of personnel.

Extenders for slow freezing are based on egg yolk as non-permeable cryoprotectant

The aim of Barex´s research towards slow freezing extenders is two-fold.

1. Development of an egg yolk based freezing medium in the form of a powder

2. Development of a freezing medium based on a powder without egg yolk



To obrain an egg yolk based extender in the form of powder, a powder was developed based on the powder of stallion semen extender Hippex supplemented with 0.3 % nanosized LDL particles from egg yolk and 2 permeable cryoprotectants. The video below shows the post-thaw motility of sperm cell that were frozen in this particular extender.

To obtain a powder for a freezing medium that is not based on egg yolk, Hippex powder was mixed with lipoprotein of vegetable origin. The video below shows post-thaw motility of stallion semen frozen in this particular extender.

Barex Biochemical Products

The art of semen preservation

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