203TIMING OF IN VITRO OOCYTE MATURATION IN SPRINGBOK (ANTIDORCAS MARSUPIALIS), BLACK WILDEBEEST (CONNECHAETES GNU), BLESBOK (DAMALISCUS DORCUS PHILLIPSI), AND REEDBUCK (REDUNCA ARUNDINUM)

Abstract

With an increased need for genetic diversity within populations, assisted reproductive technology is becoming an important tool for banking semen and embryos, with the possibility of future AI or embryo transfer between distant populations. Previous research has demonstrated that the broad approach of applying bovine IVM/F/C protocols to African antelope is inefficient for embryo production. The purpose of this study was to determine the timing of oocyte maturation (to telophase or metaphase II) in vitro in springbok (Antidorcas marsupialis; n=84), black wildebeest (Connechaetes gnu; n=18), blesbok (Damaliscus dorcus phillipsi; n=9), and reedbuck (Redunca arundinum; n=1). Ovaries were collected within 4h of death from culled animals on game reserves in South Africa, placed into warm SOF-HEPES, sliced and cumulus-oocyte complexes (COCs) collected. Complexes were placed into GMat medium supplemented with 0.01UmL−1 each FSH and LH, 50ngmL−1 EGF, and 1.0% (v/v) PSA (100U penicillin mL−1, 100μg streptomycin mL−1, 0.25ng amphotercin mL−1). Oocytes were removed from medium after 16, 20, 24, 28 or 32h of maturation in 5% CO2 in air at 39°C. After removal, complexes were denuded with hyaluronidase, mounted on a slide and placed into 3:1 (ethanol:glacial acetic acid) fixative until time of analysis. Oocytes were stained with aceto-orcein, and nuclear maturation was evaluated with a phase contrast microscope. As shown in the Table 1, in springbok (n=311), the percentage of mature oocytes peaked at 28h of maturation and was not different (P<0.05) from oocytes matured for 32h. Fewer springbok oocytes were mature at 16, 20 and 24h. Black Wildebeest (n=88) oocytes were mature by 24h, with no additional increase in maturation at 28 or 32h. Blesbok oocytes (n=42) were not mature at 16 or 20h, and there was no difference (P>0.05) in the percentage of oocytes mature at 24 or 28h. Observational data in reedbuck (n=10) indicated that no oocytes were mature at 20 or 24h, but 25.0% were mature at 28h. The low occurrence of mature oocytes at 28h in blesbok and reedbuck suggests that additional time points should be examined later in maturation. This study demonstrates that oocytes of these species can be successfully matured in vitro, but the rate of maturation and thus the optimal time of insemination for IVF is species specific. Table 1 Timing of in vitro oocyte nuclear maturation to telophase or metaphase II in springbok, black wildebeest and blesbok