Post-thaw storage of sperm from various salmonid species

Abstract

The effects of post-thaw storage on the motility and fertilizing capacity of cryopreserved sperm were investigated in four salmonid species, including the Adriatic grayling (Thymallus thymallus; five males), rainbow trout (Oncorhynchus mykiss; six males), marble trout (Salmo marmoratus; five males) and the brown trout (Salmo trutta m. Fario; six males). The sperm of rainbow trout and marble trout was cryopreserved in the presence of either methanol or dimethyl-sulfoxide (DMSO) as a cryoprotectant; for the sperm of the Adriatic grayling and brown trout, only methanol was used. A 1-h storage of sperm did not reduce the fertilizing capacity of the three species, whereas in the marble trout a gradual decrease in the percentage of eyed eggs in parallel with post-thaw storage time was observed. The use of methanol was found to result in higher fertilization than that of DMSO in the rainbow trout and marble trout. Remarkably high post-thaw motility expressed in % motile cells was observed following post-thaw storage of brown trout sperm for 10 (53 ± 12%) or 60 (56 ± 15%) min. The results indicate that immediate use of cryopreserved sperm for fertilization following thawing is not mandatory to attain successful fertilization.