Cumulus-oocyte complexes (COC) were collected from abbatoir-derived llama ovaries and cultured in vitro for 28, 30, or 36 h at 39°C in 5% CO 2 to determine the time required for maturation. The majority of COC (n = 298, 87%) were classified as categories 1 and 2 (COC with ≥5 layers or 2-4 compact layers of cumulus cells, respectively) and homogeneous ooplasm, and the proportion that underwent nuclear maturation (MII) was 78, 81 and 80%, after 28, 30 and 36 h, respectively (P = 0.65). To compare the effectiveness of FSH versus eCG for inducing in vivo maturation, in experiment 2, llamas (n = 20 per group) were treated with: (1) 25 mg FSH, twice-daily for 4 day, plus 5 mg armour of LH at the end of FSH treatment; or (2) 1000 IU of eCG, plus 5 mg armour of LH 4 day after eCG treatment. The FSH- and eCG-treated groups did not differ (P = 0.85) with respect to the number of follicles ≥6 mm at the time of COC collection (17.9 ± 2.2 versus 17.7 ± 2.2), the number of COC collected (10.7 ± 2.1 versus 11.2 ± 2.3 per llama), or the collection rate per follicle aspirated (71 versus 74%). As well, no difference (P = 0.49) was detected between the FSH and eCG groups in the number of expanded COC collected (8.3 ± 2.1 versus 10.6 ± 2.2) or the number of COC at the MII stage (6.9 ± 1.8 versus 8.9 ± 1.9). In conclusion, llama oocytes reached MII as early as 28 h after in vitro culture and both FSH and eCG were equally effective in inducing ovarian superstimulation. Treatment with LH after either FSH or eCG superstimulation permitted the recovery of a preponderance of expanded COC in metaphase II that may be suitable for in vitro fertilization without in vitro maturation.
|Number of pages||13|
|State||Published - Jun 2005|
Bibliographical noteFunding Information:
This research was supported by grants from the Canadian Llama and Alpaca Association and the Inter-American Institute for Cooperation in Agriculture. Animals and animal maintenance were provided by Quimsachata Research Station, under the sponsorship of San Marcos University of Lima, Peru. We gratefully acknowledge Bioniche Animal Health Canada Inc. for providing Folltropin, Lutropin and Novormone. We also thank Carol Olazabal and the staff of Quimsachata Research Station for their assistance with data collection.
- Follicular aspiration
- Gonadotropin superstimulation
- In vitro maturation