Cryopreservation of equine and porcine spermatozoa with a uique freezing technology (UFT)

The cryopreservation of sperm offers several benefits to various biological sciences including clinical medicine, biotechnology and agriculture. This conservation process requires a reduction in cellular metabolism while maintaining viability and structural stability through freezing and eventually thawing thus allowing for an extension of viability past normal limitations. However, the application of sperm cryopreservation has not been successful in all species. For example in the livestock sector, advancements in semen technology have been made in the dairy industry, but not as significantly within the equine and swine areas.

Recently, a new Unique Freezing Technology (UFT) was developed to freeze foodstuffs at a quick rate while maintaining freshness. This dissertation represents the initial series of trials utilizing this new technology on cellular specimens not of meat origin. From August 2001 to March 2003, numerous ejaculates from five different Quarter Horse stallions and seven boars were collected. From these samples, over 1000 treatments were created to test various cryopreservation procedures and techniques including extenders, freezing rates, thawing rates, male influence, and storage containers. The design of this study was to improve post-thaw motility rates of stallion and boar spermatozoa.

Several factors were found to affect the post-thaw motility outcome. In the stallion trials significant factors included preparative handling, stallion influence and freezing technique. The results of the boar trials also revealed the significant influences of the pre-freezing protocols, boar influence and freezing techniques. Further testing was conducted on the boar sperm samples to evaluate the stability of the phospholipid membrane post-thaw. Large variations were noted in the amounts of lipid free radicals and lipid peroxidation from the fresh samples compared to those found from the post-thaw samples. This idea was further demonstrated by an analysis of the progressive stress accumulated during pre-freezing preparation.

The unique freezing technology could be potentially considered to be used for spermatozoa cryopreservation for swine. However, further studies need to be implemented to standardize techniques and find alternative extenders.