Influence of glucose on the sex ratio of bovine IVM/IVF embryos cultured in vitro.
The effect of glucose in the medium used during in vitro culture on the sex ratio of bovine blastocysts derived from in-vitro-matured and in-vitro-fertilized oocytes was evaluated. Oocytes were matured and inseminated with mixed sperm from three bulls and were cultured in vitro in modified synthetic oviducal fluid medium with 10% fetal calf serum, with or without glucose supplementation. The overall rate of cleaved embryos that developed to expanded blastocyst in the medium without glucose (27.0%) was significantly greater (P < 0.05) than the percentage observed when embryos were cultured in medium with glucose (17.5%). Analysis of variance was performed to analyse the effect of glucose on the proportion of male embryos reaching the blastocyst stage (or arrested at the morula stage) during Days 7 to 10. Regardless of the presence or absence of glucose in the medium, significantly (P < 0.05) more male than female embryos were harvested as expanded blastocysts on Day 7 and on Day 8 of culture. On Days 9 plus 10 of culture, a sex ratio imbalance only occurred in the absence of glucose in the culture medium (P < 0.05). Glucose did not produce any significant effect on the sex ratio of the overall number of expanded blastocysts harvested by Day 10 of in vitro culture. However a significantly greater proportion of females (P < 0.01) were found among those embryos that developed only to the morulae stage after 10 days in vitro. These results show that glucose supplementation of culture media produces a preferential loss of female embryos during culture to the blastocyst stage.
Gutiérrez-Adán
A
A
Departamento de Reproducción Animal y Conservación de Recursos Zoogenéticos, INIA, Madrid, Spain. agutierr@inia.es
Granados
J
J
Pintado
B
B
De La Fuente
J
J
D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000502:physiology; D002417:Cattle / Q000196:embryology*; D046508:Culture Techniques; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D005947:Glucose / Q000494:pharmacology*; D008297:Male; D009028:Morula / Q000187:drug effects / Q000502:physiology; D016133:Polymerase Chain Reaction; D012727:Sex Characteristics; D012732:Sex Determination Analysis; D012744:Sex Ratio
D005947:Glucose