In vitro production of pig embryos: Comparisons of culture media and boars

The utilization of in vitro produced pig embryos for commercial production or research is dependent upon the development of improved methodology. Our objective was to establish a consistent in vitro embryo production (IVP) sy stem and subsequently utilize the procedures to evaluate culture system com ponents and boar effects. To summarize the IVP system, 403 inseminated oocy tes from a total of 2243 were analyzed across 17 replicates for maturation and fertilization efficiency, while 1838 zygotes were cultured in 26 replic ates for developmental data. Penetration, cleavage and blastocyst developme nt rates were determined at 18, 44 and either 144 or 168 h post inseminatio n, respectively. Monospermic penetration averaged 31.8+/-7.3% while polyspe rmy was 30.8+/-17.2%. Cleavage rate was 44.9+/-16.1%, with 21.8+/-7.5% of f ertilized oocytes and 51.9+/-15.9% of cleaved embryos developing to blastoc ysts. For culture medium comparison, fertilized oocytes were cultured in ei ther BECM-6, BECM-7, NCSU-23 or NCSU-23aa and supplemented on Day 5 post in semination (pi) with 10% FCS. These treatments resulted in 4.0, 4.9, 19.8 a nd 13.6% (+/- 3.2%) blastocysts by Day 7 pi, with an average cell number of 44.4+/-9.0, 65.1+8.2, 61.3+/-4.5 and 64.4+/-4.8, respectively. These IVP p rocedures consistently produced zygotes from semen of several different boa rs, capable of forming blastocysts in vitro. Comparison of developmental ra tes among the boars indicated that this system is variable among boars but not strictly boar-dependant. Culture media comparisons suggest that NCSU-23 yielded a higher percentage of blastocysts than the other media in this IV P system. Published by Elsevier Science Inc.