Effect of glucose in the culture medium on development of horse oocytes matured and microfertilized in vitro.
The development of in-vitro matured and microfertilized horse oocytes was examined in vitro. Fertilized oocytes were produced by 20-h insemination of in-vitro matured and partially zona-removed oocytes with frozen spermatozoa that had been treated with caffeine/calcium ionophore A23187 (fertilization rate 34.2%, monospermy rate 76.9%). Embryonic development was assessed by the number of nuclei stained with Giemsa solution. In Experiment 1, a continuous 8-day culture of the microfertilized oocytes in TCM199 or modified synthetic oviduct fluid (m-SOF) supplemented with 10% fetal bovine serum or 0.1% polyvinyl alcohol (PVA) in 5% O2, 5% CO2 and 90% N2 resulted in very few embryos developing beyond the 8-cell stage. In Experiment 2, the effects of different glucose concentrations (0, 0.5, 5.5 mM) in m-SOF/PVA during Days 1-4 and Days 5-8 of culture were examined. Proportions of oocytes having more than one nucleus ranged from 17.7% to 44.7% among the combinations of glucose concentrations. Supplementation with glucose at 0.5 mM during Days 1-4 followed by 5.5 mM during Days 5-8 resulted in the best embryo development; 12/55 (21.8%) nuclei-positive oocytes developed to the 8-16-cell stage, 11 (20.0%) developed to the 17-50-cell stage, and 5 (9.1%) comprised more than 50 cells and were assumed to be at the morula stage.
Azuma
T
T
Laboratory of Horse Production, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
Choi
Y H
YH
Hochi
S
S
Oguri
N
N
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D003470:Culture Media; D005260:Female; D005307:Fertilization in Vitro; D005947:Glucose / Q000494:pharmacology*; D006736:Horses; D008297:Male; D009028:Morula / Q000502:physiology / Q000648:ultrastructure; D009865:Oocytes / Q000254:growth & development*
D003470:Culture Media; D000001:Calcimycin; D002110:Caffeine; D005947:Glucose