The Cryopreserved Sperm Traits of Various Ram Breeds: Towards Biodiversity Conservation

SIMPLE SUMMARY: Biodiversity protection is one of our most important challenges today. Local animal breeds, as an essential piece of cultural heritage, form integral part of the biodiversity of individual countries and regions. Cryopreservation of sperm is one of the powerful tools for the conservation of animal genetic resources by creation of gene banks containing long-term stored genetic material. Cryopreservation of ram sperm faces several obstacles, such as the possible influence of individuality and breed characteristics on resistance to damage caused by low temperatures. In our research, we deal with the investigation of these differences between various breeds bred in Central Europe. ABSTRACT: The aim of our research was to compare three Slovak sheep breeds in the quality parameters of cryopreserved sperm. The ejaculates of Slovak Dairy (SD), Native Wallachian (NW), and Improved Wallachian (IW) sheep rams (n = 12) were collected by electro-ejaculation. Heterospermic samples were created from suitable ejaculates, separately for each breed (at least 90% of total and 80% of progressive motility). Samples were equilibrated in a Triladyl(®) diluent and frozen by automated freezing. Sperm samples were subjected to the motility, morphology, (CASA), viability and apoptosis (DRAQ7/Yo-Pro-1), fertilizing capability (penetration/fertilization test (P/F) in vitro) and acrosomal status (transmission electron microscopy) assays before freezing and after thawing. It was found that there were no significant differences (p < 0.05) between the evaluated breeds in motility, viability, apoptosis, morphological properties, and fertilizing ability of cryopreserved sperm. Significant differences occurred in acrosomal status. Our results demonstrate that the use of the selected cryopreservation protocol is suitable for at least three different sheep breeds, which can greatly benefit the biodiversity protection and simplifies the creation of an animal genetic resources gene bank.