Methanol and Egg Yolk as Cryoprotectants for Atlantic

• Main Authors: Salmon Spermatozoa, Wade A. Jodun, Kim King, Pat Farrell, William Wayman
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.585.8885; http://www.fws.gov/northeast/fisherycenter/pdfs/Jodun_etal_2007_cryo.pdf

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. Despite decades of stocking, sea-run returns of