Cryopreservation of spermatozoa of the barramundi,Lates calcarifer (Teleostei: Centropomidae)

Three cryoprotectants, dimethylsulphoxide (DMSO), glycerol and methanol, were tested for their ability to cryopreserve viable sperm from Lates calcarifer. The dilution ratio of milt to diluent was 1:4 (v:v) and the initial freezing rate was 31°C/min. DMSO at a concentration of 5% with either 15% milk powder or 20% egg yolk gave the best results (post-thaw motility of spermatozoa: 70–100% for 7 min). Glycerol gave acceptable results when used at high concentration (20%) with 15% milk poweder. Methanol provided little protection against freezing damage.