RESEARCHES OF SPERM CRYOPRESERVATION ON POLIODON (POLYODON SPATHULA) FOR OPTIMIZATION OF SPAWNING BIOTECHNOLOGY

The paper presents the experiments of sperm cryopreservation on poliodon (Polyodon spathula), recently acclimated sturgeon in Romania. Hormonal induction was accomplished using Nerestin 5A as follow: males were injected intramuscular with Nerestin 5A at a dose of 0.1 ml/kg body weight. Females were injected with Nerestin 5A in a total dose of 1.2 ml/kg administered in a preliminary injection (0.2 ml/kg) and a releaser injection (1.0 ml/kg) within 12 hours. The eggs were harvest by MIST method [5]. The accomplished research has been to determine the effect of using methanol (MeOH) and dimethyl sulfoxide (DMSO) as cryoprotectants in combination with two extenders (modified Tsvetkova's extender: mT and modified Hanks' balanced salt solution: mHBSS) on the spermatozoa motility and fertilization and hatching percentage of eggs by use of thawed sperm. The best post thawed motility (78 5 %) was recorded using modified Tsvetkova's extender: mT with 10 % MeOH, and the best fertilization and hatching percentage of eggs were achieved by using mT extender in combination with 5 % MeOH. The results confirm data from literature (Detlaf et al. 1993, Mims et al. 2000, Akos Horvath et al. 2006) reporting that MeOH is a proper cryoprotectant for freezing poliodon sperm