Differences between strains in the tolerance to testis cryopreservation in the silkworm, Bombyx mori

Long-term cryopreservation of the Bombyx mori silkworm is currently performed using ovaries and mature sperm. These methods have been in practice in the cryopreservation of many silkworm strains. Development of multiple methods for the safe preservation of bioresources is desirable. In this study, we investigated the potential for silkworm testis cryopreservation. We show here that the viability of cryopreservation using testis varied among the strains. For viable long-term testis cryopreservation, increasing the success rate for low fertility strains is essential. We investigated a vitrification method for testis using aluminum cryo-plates. There was the possibility, however, more experiments are required to improve this vitrification method for silkworm testis cryopreservation.