Methanol and Egg Yolk as Cryoprotectants for Atlantic Salmon Spermatozoa

• Published in: North American Journal of Aquaculture
• Main Authors: Jodun, Wade A., King, Kim, Farrell, Pat, Wayman, William
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1577/a05-052.1; https://afspubs.onlinelibrary.wiley.com/doi/pdf/10.1577/A05-052.1

Abstract The effects of four extenders on the fertilization rates of eggs fertilized with cryopreserved sperm of Atlantic salmon Salmo salar were tested. We used (1) glucose extender (54.04 g glucose/L and 1.7 g KCl/L) with 5% DMSO, (2) glucose extender with 5% DMSO supplemented with 13.3% egg yolk, (3) glucose extender with 10% methanol, and (4) glucose extender with 10% methanol supplemented with 13.3% egg yolk. Fertilization rates, expressed as the percentage of eyed embryos, ranged from 52.7% to 83.5%. Sperm cryopreserved with the glucose extender and 10% methanol supplemented with 13.3% egg yolk yielded significantly higher fertilization rates (83.5%) than did sperm cryopreserved with the other three extenders. Our fertilization rates compare favorably with those observed for eggs from the same year‐class fertilized with fresh milt (81.4%) and reared at the White River National Fish Hatchery. The presence of egg yolk in extenders incorporating 10% methanol provided additional protection to salmonid sperm during the freezing and thawing processes and resulted in an increase in survival from 72.9% to 83.5%. However, the cryoprotective effect of egg yolk may be specific to the individual formulation of extenders. In our trials, glucose and 5% DMSO without egg yolk yielded a 66.9% fertilization rate, while glucose and 5% DMSO supplemented with 13.3% egg yolk produced only 52.7% fertilization after cryopreservation.