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

363 ENHANCEMENT OF COMMERCIAL BOVINE IN VITRO EMBRYO PRODUCTION BY SEXING FROZEN SEMEN PRIOR TO INSEMINATION

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

Bioembryo - Animal Reproduction Biotechnology, Bauru, Sao Paulo, Brazil

Reproduction, Fertility and Development 22(1) 338-338 http://dx.doi.org/10.1071/RDv22n1Ab363
Published: 8 December 2009

Abstract

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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