CRYOPRESERVATION AND VIABILITY OF SPERMATOZOA FROM THE ORNAMENTAL JAPANESE CARP (NISHIKIGOI)

The establishment of a bank of gametes (spermatozoa and egg) or embryo s of cultured fish is obviously economically advantageous. It allows l ong term preservation of genetic traits obtained through traditional s elective breeding, gynogenesis, androgenesis and transgenic fish produ ction programs. In our attempts to form a spermatozoa bank for fish sp ecies cultivated in Israel, we report on preliminary results of cryopr eservation of spermatozoa obtained from the ornamental carp (nishikigo i). The viability of spermatozoa subjected to cryopreservation was ass essed by observing its motility and comparing the percent of fertilize d eggs produced with the frozen spermatozoa with the percent fertilize d by unfrozen spermatozoa. The most important factors affecting viabil ity were: (1) the extender and cryoprotectant solutions used during fr eezing, (2) the cooling procedure and (3) the quality of the eggs. Ass essing the percent of viable spermatozoa is essential to determine the amount of spermatozoa required to fertilize a given number of eggs an d, thus, the amount necessary to store in the bank.