Effects of in vitro fertilization conditions on preimplantation development and quality of pig embryos.
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.
Koo
Deog-Bon
DB
Laboratory of Development and Differentiation, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong, Daejeon.
Kim
Yong-Jun
YJ
Yu
Iljung
I
Kim
Ha-Na
HN
Lee
Kyung-Kwang
KK
Han
Yong-Mahn
YM
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