The study investigated the effects of sperm sorting, capacitation treatment and co-cultivation on sexed bovine in vitro embryo production. The effect of treatment and co-culture on production of embryos of the preferred sex from unsorted sperm was also studied. Sperm from five breeding bulls was used for fertilization of mature oocytes as follows: Experiment 1, sorted and unsorted sperm (bulls A-E) treated only with heparin in standard co-cultures; Experiment 2, sorted sperm (bulls A-E) treated with heparin-PHE (penicillamine, hypotaurine, and epinephrine) or heparin-caffeine in drop co-cultures; and Experiment 3, unsorted sperm (bull E) treated with either heparin-PHE or heparin-caffeine in both standard and drop co-cultures. In all bulls, treatment with heparin resulted in significantly (p < .05) reduced cleavage and blastocyst rates from sorted sperm, as compared with those from unsorted sperm. In bulls A, B, D and E, treatment of sorted sperm with heparin-PHE in drops significantly increased the blastocyst rate (p < .05). In unsorted sperm of bull E, heparin-PHE treatment in drops resulted in the XX/XY sex ratio inverse to that obtained by heparin-caffeine treatment in standard co-cultures (32.3%/67.7% and 66.7%/33.3%, respectively). In conclusion, the treatment of sorted sperm with heparin-PHE in modified drop co-cultures can be recommended for production of in vitro sexed embryos. The use of unsorted sperm for production of embryos of the preferred sex by selected capacitation treatment and co-culture can be the method of choice in bulls with low IVF yields from sorted sperm.

Department of Genetics and Reproduction Veterinary Research Institute Brno Czech Republic

Department of Histology and Embryology Poznan University of Medical Science Poznan Poland

Institute of Animal Physiology and Genetics Academy of Sciences of the Czech Republic Libechov Czech Republic

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