Lahnsteiner, F., Weismann, T., Patzner, R.A.-1997
Aquaculture Research, 28 (6): 471-479
Abstract:
For salmonid semen, the cryoprotective action of 10% methanol was compared with a 5% glycerol mixture, until now one of the most effective cryoprotectants. In Oncorhynchus mykiss (Walbaum), Salmo trutta L. f. fario, Salmo trutta L. f. lacustris and Salvelinus alpinus (L.), semen cryopreserved with both cryoprotectants yielded post-thaw fertilization rates of 90-100% of control with untreated semen at sperm-to-egg ratios of 1.8 x 10^6-2.4 x 10^6 spermatozoa per egg. However, at sperm-to-egg ratios of 0.9 x 10^6-1.2 x 10^6 spermatozoa per egg, semen cryo-preserved with methanol had significantly higher fertilization rates than semen frozen with the DMSO/glycerol mixture. In other studies we obtained similar data for Coregonus sp., Salvelinus fontinalis (Mitchill), Thymallus thymallus (L.) and Hucho hucho (L.), proving that methanol is the most effective and generally applicable cryoprotectant for semen of the studied salmonid species.
To facilitate the insemination of large egg batches we investigated the suitability of 1.2 ml and 5 ml straws for deep freezing of semen of Oncorhynchus mykiss, Salmo trutta L. f. fario, Salmo trutta L. f. lacustris and Salvelinus alpinus. With 1.2 ml straws the fertilization rates were similar to 0.5 ml straws when using lower freezing and higher thawing temperatures. The 5 ml straws resulted in a fertilization success of only about 40 % of fresh semen control.
(Institute for Zoology, University of Salzburg, Salzburg, Austria)
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