Preservation of spermatozoa at low temperatures by the use of long chain alcohol

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 09660301
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied animal science
• Research Institution: Shizuoka University
• Principal Investigator: BAMBA Kimio Faculty of Agriculture, Shizuoka University Professor, 農学部, 教授 (00022070)
• Project Period (FY): 1997 – 1999
• Keywords: lauryl alcohol / spermatozoa / cold shock / cryopreservation / boar / bull / dog / deer

Research Abstract

Long chain alcohols of which carbon number is 10 to 14 protect boar spermatozoa from cold shock injuries efficiently.
The present study was made to develop techniques for low temperature preservation of mammalian spermatozoa by the use of lauryl alcohol (LAl) or 1-dodecanol. The effects of LAl are depend upon sperm and/or lipids concentration in diluted semen. Inclusion of a variety of lipids (plant, animal and mineral sources) decreased the toxic effects of LAl, and consequently increased protective action against cold shock injuries. The optimal concentrations of LAl and olive oil were 0.02 and 0.4% respectively (semen containing 4x108/ml was diluted 1:1 with diluent). When dispersed in BTS diluent by sonication, they might form LAl-oil complexes. The effectiveness of the diluent disappeared after filtration with Millipore filter of which pore size was 0.22 μm. Olive oil would play a role of reservoir of LAl. Freeze fracture electron microscopic study revealed that the proportion of s permatozoa displaying aggregation of intramembranous particles after cold shock decreased in the presence of LAl. It is therefore suggested that LAl exerts protective effects through maintaining the sperm membrane fluidity at reduced temperatures.
Boar semen was successfully stored at 5℃ by the use of BTS containing 0.0025% LAl and 0.05% olive oil (semen:diluent=1:3). A total of 40 sows or gilts were inseminated with semen stored up to 6 days. The pregnancy rate was 80%(32/40) and the average litter size (n=22) was 10.6.
Utility of LAl for deep freezing of boar, bull, dog and wild deer spermatozoa was tested. The optimal concentration of LAl in freezing medium containing 20% egg yolk was 0.05% in boar spermatozoa. The inclusion of 0.05% LAl was effective for the maintenance of the viability (particularly acrosomal integrity) of these spermatozoa during freezing and thawing. LAl can be dissolved in diluents without sonication when LAl was previously mixed with triethanolamine lauryl sulfate (LAl: 40% TL= 1:9).