Use of different nonglycolysable sugars to maintain stallion sperm viability when frozen or stored at 37 degrees C and 5 degrees C in a bovine serum albumin medium.

The research paper investigated how different types of sugars affect the survival and viability of stallion (male horse) sperm. The authors specifically looked at how these impacts vary when the sperm are stored at different temperatures or are frozen.

Methods and Sugars Tested

• The researchers conducted experiments with bovine serum albumin (BSA), a substance often used in biology for a range of procedures including stabilizing some other proteins.
• They mixed BSA with different types of sugars: lactose, raffinose, sucrose, arabinose, or galactose, to see how these combinations affected stallion sperm viability.
• The viability was determined using two parameters: the percentage of motile (moving) sperms and their rate of forward movement.

Results at Different Temperatures

• The researchers found that the BSA diluents mixed with either lactose, raffinose, or sucrose were equally effective in maintaining sperm viability when stored at both 37 degrees Celsius (the body temperature of horses) or 5 degrees Celsius for 24 hours.
• Interestingly, these combinations preserved sperms’ ability to move better than BSA mixtures with arabinose or galactose.
• The galactose and arabinose BSA solutions had a detrimental effect on the sperm, reducing both their movement and viability. However, there wasn’t significant difference between these two sugars in terms of their impact on the sperm health.

Comparison between Fresh and Frozen Sperm

• The researchers also examined whether extended viability in BSA diluent pairs varied between freshly collected spermatozoan and those frozen then thawed. They found no significant difference between the two classifications when paired with lactose, raffinose, or sucrose.
• Their results also showed that the freezing process did not suit spermatozoa from around 75% of the stallions tested, as they did not survive.

Conception Rate

• They achieved a conception rate – the rate at which insemination led to pregnancy – of 32% using the frozen-thawed spermatozoa that had been stored in the BSA and sugar combinations.
• This was lower than the 41% conception rate achieved with fresh semen in a different study, but still represented 78% of that higher rate, making the freezing and thawing method a relatively successful one.