Improvement in non-programmable sperm cryopreservation technique in farmed greenlip abalone Haliotis laevigata

• Glucose, fructose and galactose showed a similar cryoprotective effect.
• The addition of 0.6% glycine has improved the post-thaw fertilization rate to 96%.
• Substantial reduction in sperm to egg ratio is required for post-thaw fertilization.

This study assessed the effects of the addition of vitamins (l-ascorbic acid), amino acids (glycine and taurine), and monosaccharides (glucose, fructose and galactose) on sperm cryopreservation using a non-programmable freezing technique in farmed greenlip abalone. The results showed that the addition of taurine, glycine or l-ascorbic acid significantly improved the post-thaw sperm motility, whereas the post-thaw sperm fertilization rates were improved by the addition of glycine or l-ascorbic acid. Flow cytometry analysis demonstrated that the addition of glycine significantly enhanced the post-thaw sperm plasma membrane integrity and acrosome integrity. Results from the investigation on monosaccharides demonstrated that glucose, fructose and galactose had a similar cryoprotective effect, resulting in a similar level of the post-thaw sperm fertilization rate, plasma membrane integrity, mitochondrial membrane potential and acrosome integrity. In this study, the highest post-thaw fertilization rate of 96% was achieved by using the cryoprotective mediums containing 6% DMSO, 1% glucose and 0.6% glycine.