In vitro and in vivo maturation of llama oocytes.
Cumulus-oocyte complexes (COC) were collected from abbatoir-derived llama ovaries and cultured in vitro for 28, 30, or 36 h at 39 degrees C in 5% CO2 to determine the time required for maturation. The majority of COC (n=298, 87%) were classified as categories 1 and 2 (COC with > or =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 > or =6mm 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.
Ratto
Marcelo
M
Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
Berland
Marco
M
Huanca
Wilfredo
W
Singh
Jaswant
J
Adams
Gregg P
GP
D000818:Animals; D002161:Camelids, New World; D002467:Cell Nucleus / Q000502:physiology; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006736:Horses; D007986:Luteinizing Hormone / Q000494:pharmacology; D009865:Oocytes / Q000254:growth & development*; D006080:Ovarian Follicle / Q000166:cytology; D013997:Time Factors
D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone