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This Article Full Text Full Text (PDF) All Versions of this Article: 79/4/594    most recent biolreprod.108.070169v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Bermejo-Álvarez, P. Articles by Gutiérrez-Adán, A. PubMed PubMed Citation Articles by Bermejo-Álvarez, P. Articles by Gutiérrez-Adán, A. Agricola Articles by Bermejo-Álvarez, P. Articles by Gutiérrez-Adán, A.

Can Bovine In Vitro-Matured Oocytes Selectively Process X- or Y-Sorted Sperm Differentially?¹

Departamento de Reproducción Animal y Conservación de Recursos Zoogenéticos,³ INIA, 28040 Madrid, Spain Department of Biotechnology,⁴ Institute of Animal Breeding (FAL), 31535 Neustadt, Germany School of Agriculture, Food Science and Veterinary Medicine,⁵ University College Dublin, Dublin 4, Ireland

ABSTRACT

It has been reported that the mammalian female could have a preconceptual influence on the sex of her offspring, and it has been hypothesized that this influence could go some way toward accounting for the reported lower fertility following insemination with sex-sorted sperm. To test whether in vitro matured oocytes are able to select X- or Y-bearing spermatozoa following in vitro fertilization (IVF), we fertilized in vitro 1788 oocytes with X-sorted semen, Y-sorted semen, a mix of X- and Y-sorted semen, and unsorted semen from the same bull, and cultured until Day 9. Fertility was assessed by recording cleavage rate at 48 h postinsemination (hpi) and blastocyst development until Day 9. Embryos were sexed at the two- to four-cell stage and the blastocyst stage. The proportion of zygotes cleaving at 48 hpi was not different between X- and Y-sorted groups and the mix of X- and Y-sorted semen group; however, all were significantly lower than the unsorted group (P < 0.001). Blastocyst yield on Day 6 was significantly higher (P 0.01) in the control group compared with the rest of the groups. Cumulative blastocyst yields on Days 7, 8, and 9 were also significantly higher (P 0.01) in the unsorted group compared with the sorted groups. The proportion of female and male two- to four-cell embryos obtained following IVF with X- and Y-sorted sperm was 88% and 89%, respectively and the sex ratio at the two- to four-cell stage was not different following IVF with unsorted or sorted/recombined sperm (56.9% males vs. 57% males, respectively). At the blastocyst stage, similar percentages were obtained. In conclusion, the differences in cleavage and blastocyst development using sorted versus unsorted sperm are not due to the oocyte preferentially selecting sperm of one sex over another, but are more likely due to spermatic damage caused by the sorting procedure.

animal reproduction technology, fertilization, in vitro fertilization, male and female bovine embryos, sex-sorted sperm

¹Supported by the Grants, AGL2006-04799 to A.G.-A., and AGL2006-05616 and AT2006-003 to D. Rizos from the Spanish Ministry of Science and Technology. P.B.-Á. was supported by a FPU grant from the Spanish Ministry of Education and Science. P.L. is funded by Science Foundation Ireland.

Correspondence: ²Alfonso Gutiérrez-Adán, Departamento de Reproducción Animal y Conservación de Recursos Zoogenéticos, INIA, Ctra de la Coruña Km 5.9, Madrid 28040, Spain. FAX: 034 91 347 4014; e-mail: agutierr{at}inia.es