Exploring rabbit semen cryopreservation and the crucial role of cryobank: unveiling advantages and promising perspectives

Over the years, efforts have been made to establish a reference protocol for the first Italian rabbit semen bank. Here, we will provide an overview of our group’s key discoveries, which have led us to identify an effective freezing protocol for rabbit semen. However, a drawback of our protocol involves diluting the semen with the freezing media at fixed dilution ratios, resulting in significant variability in the sperm number per straw. Addressing this limitation underscores the need to standardise the freezing protocol by investigating the effect of sperm concentrations within straws on the reproductive performances of cryopreserved rabbit semen. In this regard, in an in vivo trial, 192 multiparous receptive rabbit does were randomly assigned to six treatment groups, including a control group. The remaining groups were inseminated with doses containing 15, 25, 35, 55 and 75×106 sperm, respectively. Sperm concentrations of 25, 35 and 55×106/straw exhibited higher reproductive performances compared to other tested concentrations and were akin to fresh semen. Through the adoption of freezing protocols with standardised sperm concentrations, cryobanks can safely preserve rabbit population genetic resources, offering invaluable support for future breeding and research efforts.