Fertilizing ability of cryopreserved spermatozoa in the Persian sturgeon (Acipenser persicus) and stellate sturgeon (A. stellatus)

Motility of spermatozoa was studied on ۱۲ and ۷ specimens of Acipenser persicus and A. stellatus, respectively. The density measured to be ۲.۲۲±۰.۶۵x۱۰۹ml-۱ in A. persicus and ۲.۲۱±۰.۵۵x۱۰۹ml-۱ in A. stellatus. Semen samples were diluted with two extenders containing tris ۱۱۸mM, sucrose ۲۳.۴mM, pH=۸, egg yolk (۲۰%), dimethyl sulfoxide (۱۵%) and penicillin potassium (۵۰۰IU/ml) and biociphus extender containing glycerol as a cryoprotectant at a ratio of ۱:۱ and then transferred to ۰.۵ml straws and frozen in a computer controlled low temperature apparatus and stored in liquid nitrogen for one week. To study fertilizing ability, the spermatozoa were then used to inseminate eggs after thawing. Mean sperm motility in fresh spermatozoa was ۸۶.۶% in A. persicus and ۷۳.۷۵% in A. stellatus which decreased to ۳۲.۲% (p<۰.۰۰۱) and ۳۷.۵% (p<۰.۰۰۱) in frozen spermatozoa, respectively. Also mean fertilization rate decreased from ۹۰.۴% to ۳۰.۷% in A. persicus and from ۷۲% to ۳۶.۸% in A. stellatus.

Keywords:

A. persicus , A. stellatus , Spermatozoa , Cryopreservation , DMSO , Glycerol