Reproduction, Fertility and Development Reproduction, Fertility and Development Society
Vertebrate reproductive science and technology


D. B. Ardais A , L. T. S. Yamazaki A , L. P. Landim Junior A , E. C. D. Benzi A , D. P. Corneglian A , M. Romano A , A. Castro Netto A , F. Guidorizzi A , G. L. Santos A and W. Yamazaki A
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Bioembryo - Animal Reproduction Biotechnology, Bauru, Sao Paulo, Brazil

Reproduction, Fertility and Development 22(1) 338-338
Published: 8 December 2009


The high commercial demand on production of genetically valuable female cattle was emphasized after use of sex-sorted semen in commercial in vitro embryo production (IVEP) programs and a reduction of interest in the use of embryo biopsy followed by PCR. Brazil is a leader in IVEP of bovine embryos, and frozen-thawed, sex-sorted samples become a new option for embryo sexing. There are only a few reports in the literature using this new technique for IVEP. Most reports have involved the use of frozen-thawed then sorted for use with AI in Europe. In the present study, frozen semen from three Nelore bulls was used and the blastocyst production rate was evaluated at Day 7 of IVP and compared to previous data from the same bulls and a batch of non-sorted semen. Cumulus oocyte complexes obtained from high genetic merit donors by ovum pickup were matured (TCM-199, supplemented with FCS, LH, FSH, estradiol, pyruvate, and antibiotics) for 24 h and fertilized (Fert-TALP supplemented with BSA, phenylalanine, and heparin) for 18-22 h (Day 0) in vitro. Frozen semen straws were thawed at 35°C for 30 s in a water bath and then selected by centrifugation at 800 g on discontinuous Percoll™ gradients (45 :90%). Samples of frozen-thawed sex-sorted semen were processed from straws from bulls that in some cases may already be dead. Frequently, 3 to 5 straws were thawed, flow-sorted, and then centrifuged to provide sufficient sperm to fertilize 100 oocytes. On Day 1, presumptive zygotes were transferred to culture media (SOFaa supplemented with BSA and FCS) and on Day 7 blastocyst production rate was evaluated. The present results were commercially satisfactory because the frozen-thawed sex-sorted semen from all three bulls performed comparably and, in one case, better than non-sorted semen from the same bulls. Therefore, its use is extremely attractive in commercial bovine IVEP systems and is a more efficient system than embryo sexing.

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