title: In vitro evaluation of in vivo fertilizing ability of frozen rabbit semen.
abstract: The present work studied different spermatozoa parameters and the ability of frozen rabbit spermatozoa to fertilize, in vitro, in vivo-matured oocytes, as a test to predict their in vivo fertility and prolificacy. Semen from rabbit bucks was frozen using two freezing protocols [in a freezer at -30 degrees C or in liquid nitrogen vapour (LNV)]. For the in vivo trial, females were inseminated with frozen-thawed spermatozoa. Oocytes used for in vitro testing were recovered 14 h after ovulation induction from donors and co-incubated with 2 x 10(6) frozen-thawed spermatozoa during 4 h at 37 degrees C in Tyrode's medium under an atmosphere of 5% CO(2) in air with maximal humidity. After co-incubation period, presumptive zygotes were cultured in TCM199 supplemented with 20% foetal bovine serum (FBS), under the same conditions described above. Although no statistical differences were observed between freezing protocols in seminal parameters [motility rate: 40 and 35%, VCL: 35 and 46 microm/s, amplitude of lateral head displacement (ALH): 1.7 and 2.4 mum, for semen frozen at -30 degrees C and in LNV, respectively], significant differences were noted in the fertilizing ability in vivo and in vitro. Semen frozen at -30 degrees C showed the highest fertilizing ability in vitro (26.7% vs 6.2 and 8.7% for semen frozen at -30 degrees C, in LNV and fresh semen, respectively) and the lowest fertility rate in vivo (21.7% vs 64.2% and 70.6% for semen frozen at -30 degrees C, in LNV and fresh semen, respectively). Sperm frozen at -30 degrees C seemed to be more capacitated.
authors.affiliation: Centro de Investigación y Tecnología Animal, IVIA, Valencia, Spain. mpviudes@ivia.es
authors.forename: M P
authors.initials: MP
authors.lastname: Viudes-de-Castro
authors.forename: E
authors.initials: E
authors.lastname: Mocé
authors.forename: J S
authors.initials: JS
authors.lastname: Vicente
authors.forename: F
authors.initials: F
authors.lastname: Marco-Jiménez
authors.forename: R
authors.initials: R
authors.lastname: Lavara
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents; D005260:Female; D005298:Fertility / Q000502:physiology*; D005307:Fertilization in Vitro / Q000662:veterinary*; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011817:Rabbits / Q000502:physiology*; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013075:Sperm Capacitation; D013079:Sperm Maturation; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents