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Barex Biochemical Products celebrates Hippex's 5th anniversary with new introductions (2021).

Hippex stallion semen extender for chilled storage of diluted stallion sperm has been successful for five years. Over the past years, we have seen an increase in sales yearly. Hippex excels in the high progressive motility of sperm cells during storage and an extended preservation capacity. Hippex outperforms other extenders regarding fertility, which is between 75 and 80%. This is 10-15% higher than any other commercial stallion semen extenders. The success of Hippex can be illustrated by the fact that Hippex has been used at famous stallion AI Centers such as Schockemöhle and  Helgstrand for several years. With the marketing efforts of Leo Vankrieken and Pierre Warmoes of HuVeSearch started last year, we have seen further sales and promising prospects.

The Hippex extender is a powder extender, which means that Hippex is sold as a powder in various volumes and presentations. Before diluting the ejaculate, the powder can easily be dissolved in water. The production of the powder has several advantages, including that it can quickly be shipped at ambient temperature worldwide. But otherwise, powder is better in terms of stability and shelf life of the product.

The chilled storage of stallion sperm for artificial insemination in the horse breeding season is done by diluting the stallion's ejaculate with so-called preservation media or extenders. Improving the preservation capacity of stallion sperm by using extenders remains an ongoing challenge.

It is well known that there is a high correlation between progressive motility of sperm cells and fertility.  The movement of sperm cells requires much energy, which comes from either conversion of glucose (glycolysis) or respiration (oxidative phosphorylation). Stallion sperm relies mainly on respiration. Consequently, reactive oxygen species or free radicals are produced as byproducts. The free radicals oxidize lipids and thereby affect the fluidity of the outer sperm membranes.  In particular, the unsaturated fatty acids are oxidized, which are the types of fatty acids that ensure the fluidity of the membranes and, thus, the motility of the sperm cells.

Another challenge is the presence of seminal proteins that induce capacitation by removing lipids and cholesterol from the pouter sperm membrane. Specific seminal proteins act as initiators of a series of biochemical processes to prepare the sperm cell for fusion with the egg cell.

Thus, prevention of oxidation of lipids or repair of the damaged membranes on the one hand, and removal or binding (and thus abolishing their effect) of the seminal proteins are two main routes in developing stallion semen extenders.

Those mentioned above led to the development of Hippex, in which different proteins exert their protective effect against the seminal proteins in two ways: binding (and thus preventing their action) of these seminal proteins and shielding the sperm cell from these seminal proteins. Different types of proteins provide this protection to varying degrees. Further, antioxidants - simple molecules but proteinaceous substances - prevent oxidation as much as possible. In contrast, as part of larger molecules, highly purified polyunsaturated fatty acids replace damaged lipids from the outer sperm cell membrane.


The challenges described above have been investigated further, leading to the development of 3 additional products.

The first addition is the Hippex Centrifugation Medium (HCM). In addition to the Hippex ingredients, HCM contains protective proteins that form a protein cloud surrounding the sperm cells. The cloud acts as a protective shield against possible damaging effects of the centrifugation process. It is a soft cushion on which the sperm cells can precipitate. Further, these additional proteins protect the cells against the potentially damaging effect of the seminal proteins that can take place before and during centrifugation. This protection must take place as soon as possible after ejaculation. It is even preferable to put some HCM in the collecting beaker where the ejaculate is harvested.


Hippex is suitable for most stallions (about 90%) to dilute and preserve sperm cells. But in the case of about 10% of all stallions, one is dealing with sperm of low quality. To serve stallion owners with supreme extenders, particularly for these stallions, two additional extenders have been developed, namely Hippex Plus and Hippex Prime.


Hippex Plus is also based on Hippex and contains additional ingredients from plant seed origin. These ingredients improve the quality of the sperm cells, in particular motility. Hippex Plus is particularly suited for dilution and storing low-quality stallion sperm. Further, Hippex Plus is highly suited when prolonged storage of the diluted semen for up to a week is desired.

Hippex Prime contains, in addition to the Hippex ingredients, egg yolk LDL particles that shield the sperm cell from the damaging action of specific seminal proteins.  Hippex Prime can be used to dilute and store low-quality sperm but is also highly suited when prolonged storage of the diluted semen for up to a week is desired.


The Hippex series of extenders are powder extenders. These extenders are sold as a powder in various volumes and presentations. Just before use, the powders can easily be dissolved in water. All extenders are sold as a powder and can quickly be shipped worldwide.

Hippex Prime is the first powder extender containing protective LDL particles from egg yolk. This achievement will be followed soon by the introduction of a powder to prepare cryopreservation media.

The Hippex series is being produced and sold by HuVeSearch, a company located in Pelt, Belgium (

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Barex Biochemical Products

The art of semen preservation

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