Barex Biochemical Products

The art of semen preservation

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

Hippex stallion semen extender for chilled storage of diluted stallion sperm has been successful on the market for 5 years now. Over the past years we have seen an increase in sales every year. Hippex excels in high progressive motility of sperm cells during storage and a long preservation capacity. Hippex outperforms other extenders in terms of 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 is 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 a further increase in sales and very promising prospects.

The Hippex extender is a powder extender, which means that Hippex is sold as powder in various volumes and presentations. Just before use to dilute the ejaculate, the powder can easily be dissolved in water. The presentation as powder has several advantages, among others that it can easily be shipped at ambient temperature world-wide. But otherwise, powder is simply 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 dilution of the stallion ejaculate with so-called  preservation media or extenders. To improve 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 a lot of energy which comes from either conversion of glucose (glycolysis) or respiration (oxidative phosphorylation). Stallion sperm relies mostly on respiration. As a consequence, 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.  It is in particular the unsaturated fatty acids that are oxidized and these are precisely 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. Certain seminal proteins act thereby as initiator 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.

The above mentioned 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 also proteinaceous substances - prevent oxidation as much as possible, whereas highly purified polyunsaturated fatty acids as part of larger molecules  are used to replace damaged lipids from the outer sperm cell membrane.


The challenges described above have been investigated further and led 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 kind of 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 already before and during centrifugation. This protection must takes place as soon as possible after ejaculation. It is even preferable to put some HCM in the collecting beaker in which 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. In order to serve stallion owners with supreme extenders particularly for these stallions, 2 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 in particular suited for dilution and storage of 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 among others, shield the sperm cell from the damaging action of certain seminal proteins.  Hippex Prime can be used for dilution and storage of 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. This means that these extenders are sold as 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 easily be shipped world-wide.

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

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

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