title: Effects of in vitro fertilization conditions on preimplantation development and quality of pig embryos.
abstract: The present study was to investigate the effects of in vitro fertilization conditions on in vitro development and structural integrity of pig embryos. Porcine oocytes matured in vitro were co-incubated with four different spermatozoa concentrations (0.6 x 10(5), 1.2 x 10(5), 2.5 x 10(5) and 5 x 10(5) cells/ml) for 6 h, and at a spermatozoa concentration (1.2 x 10(5) cells/ml) for 2, 4 and 6 h, respectively. Spermatozoa penetration and blastocyst formation were observed at 10 and 144 h post insemination, respectively. The allocation of a blastocyst to inner cell mass (ICM) and trophectoderm (TE) cells was determined by using a differential staining method. Polyspermy frequency increased with increasing spermatozoa concentrations. The spermatozoa-oocyte co-incubation period of 2 h provided for decreased in vitro development rate than 4 and 6 h groups (P < 0.05), although no difference was detected in polyspermy frequency between spermatozoa-oocyte co-incubation periods. Interestingly, blastocysts derived from the groups with greater spermatozoa concentrations (2.5 x 10(5) and 5 x 10(5) cells/ml) had significantly fewer ICM cell nuclei as compared with those groups with lesser spermatozoa concentrations (0.6 x 10(5) and 1.2 x 10(5) cells/ml). There was no difference in the structural integrity of blastocysts among the co-incubation periods. Blastocysts derived from respective experiments were individually classified into three groups (I: <20%; II: 20-40% and III: >40%) based on the ratio of ICM to total cells. Proportion of blastocysts in Group II, with a presumptive normal range of structural integrity, was slightly decreased in the groups with greater spermatozoa concentrations (2.5 x 10(5) and 5 x 10(5) cells/ml). The results indicate that the spermatozoa concentration during in vitro fertilization may be important for developmental competence and quality of pig embryos.
authors.affiliation: Laboratory of Development and Differentiation, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong, Daejeon.
authors.forename: Deog-Bon
authors.initials: DB
authors.lastname: Koo
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Kim
authors.forename: Iljung
authors.initials: I
authors.lastname: Yu
authors.forename: Ha-Na
authors.initials: HN
authors.lastname: Kim
authors.forename: Kyung-Kwang
authors.initials: KK
authors.lastname: Lee
authors.forename: Yong-Mahn
authors.initials: YM
authors.lastname: Han
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002478:Cells, Cultured; D046149:Embryo Culture Techniques / Q000662:veterinary; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary*; D008297:Male; D009865:Oocytes / Q000502:physiology; D013076:Sperm Count; D013552:Swine; D013997:Time Factors