Successful in vitro production of embryos in the red deer (Cervus elaphus)and the sika deer (Cervus nippon)

The aim of our study was to define the conditions for IVM and IVF of oocyte s in 2 common deer species as models for endangered related subspecies. Imm ature oocytes were recovered during the breeding season from postmortem ova ries (red deer) or by repeated laparoscopic follicular aspiration (sika dee r). Oocytes were cultured for 24 h in IVM medium supplemented with EGF or F SH and follicular fluid. Stag semen was collected by electroejaculation (bo th species) or by epididymal flushing (red deer) and cryopreserved. For IVF , oocytes were exposed to different concentrations of thawed spermatozoa in a modified Tyrode albumin lactate pyruvate medium supplemented with 20% (v /v) estrus sheep serum for 18 h. After IVF, presumptive zygotes were allowe d to develop in vitro for 7 days in synthetic oviduct fluid (SOF) supplemen ted with fetal calf serum (10%, v/v). In both species, the presence of ovin e FSH and follicular fluid improved the in vitro maturation rate. In the si ka deer, the optimal sperm concentration for IVF was 10(6)/mL and some fert ilized oocytes reached the early morula stage (20 to 25 cells). In the red deer, after IVF with ejaculated or epididymal spermatozoa (2.0 x 10(6)/mL), 20% of zygotes developed to the blastocyst stage (50 to 80 cells). (C) 200 1 by Elsevier Science Inc.