Semen from sex-reversed rainbow trout of spring strain can be successfully cryopreserved and used for fertilization of elevated number of eggs

Abstract

We attempted to cryopreserve the semen obtained from the spring strain of sex-reversed rainbow trout. Our second objective was to test the fertilizing ability of cryopreserved sperm with the use of an increasing number of eggs, in the range from 100 to 1600 in order to scale up the use of cryopreserved sperm. High sperm motility was reported after freezing–thawing. The percentage of sperm motility of cryopreserved semen (56%) did not differ from fresh semen (49%). High absolute fertilization rates of cryopreserved semen were obtained: 91.2±1.5–93.7±1.7% and 83.0±5.5–90.3±3.5% for eyed embryos and hatched larvae, respectively. No differences were recorded between egg numbers. In conclusion, we have demonstrated that an efficient cryopreservation procedure of semen of sex-reversed female rainbow trout of autumn spawning is also very effective for fish of spring spawning. It is possible to increase the number of fertilized eggs up to 1600 eggs. Therefore, it is possible to incorporate cryopreserved semen in breeding programs with the use of semen from sex-reversed females of rainbow trout of the spring strain. Statement of relevanceThis study is relevant to improvement of reproduction in aquaculture species.