Production of Female Bovine Embryos with Sperm Sorted by Magnetic Activated Cell Sorting

Sperm sexing is an efficient mean to obtain offspring with desired male and female. For sexing bovine sperm, flow cytometry has been used as a practical method. However, sperm sorting equipments are fairly expensive and complicated. Recently magnetic activated cell sorting (MACS) has been widely applied in reproductive researches because it is a relatively simple and less time consuming technique. In this study MACS was thereby performed to enrich the X-chromosome bearing sperm and to produce female bovine embryos. The sorting efficiency of MACS was calculated by fluorescence activated cell sorting (FACS). The motility of sorted X-chromosome bearing sperm was evaluated by computer-assisted analysis (CASA) prior to using them for fertilization of oocytes, and then the quality and sex of embryos were evaluated. The X-chromosome bearing sperms were significantly enriched after MACS. Sperms maintained their fertility after the MACS sorting. Curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), beat cross-frequency (BCF), amplitude of lateral head displacement (ALH) and linearity (LIN) were not dramatically decreased, but motility (MOT), mean angular displacement (MAD) and straightness of path (STR) were significantly reduced. Although the embryos derived from sorted X-chromosome bearing sperm showed decreased rates of cleavage and blastocyst formation compared to those of embryos with non-sorted sperm, there was no significant difference between embryos generated with unsorted and sorted sperm in terms of the quality of embryos. Moreover the number of female embryos was significantly increased after MACS. In conclusion, MACS effectively enriched the X-chromosome bearing sperms and produced female bovine embryos without deterioration of embryo quality. Therefore MACS is a feasible technique to sort targeted gender of sperm especially X-chromosome bearing sperm that would contribute to reducing the cost of maintaining animals of the undesired sex or to optimize numbers of animals of the desired sex in the livestock industry.