title: Maturation in vitro of pig oocytes in protein-free culture media: fertilization and subsequent embryo development in vitro.
abstract: In the present study, attempts were made to develop a protein-free (PF) in vitro maturation (IVM) system for pig oocytes and to examine subsequent embryo development after in vitro fertilization. In experiment 1, four IVM media were tested: 1) control: North Carolina State University (NCSU) 23+10% porcine follicular fluid; 2) PF-NCSU: NCSU 23+0.1% polyvinyl alcohol (PVA)+1% amino acids; 3) PF-TCM: Tissue culture medium (TCM) 199+PVA; and 4) PF-WM: PF-Waymouth MB 752/1 medium (WM)+PVA. Oocytes were cultured in the respective media containing eCG and hCG (10 IU/ml each) for 20-22 h and then without hormonal supplements for an additional 20-22 h. After culture, the degree of cumulus expansion and frequency of nuclear maturation were determined. Some oocytes were coincubated with frozen-thawed spermatozoa for 5-6 h in modified Tris-buffered medium containing caffeine and BSA. In experiment 2, oocytes were matured in control, PF-TCM, and PF-WM, fertilized in vitro, and cultured for 144 h in NSCU 23+BSA. Fewer (p < 0.01) oocytes reached metaphase II stage in PF-NCSU (45% vs. 80-85%) than in the other media. Oocytes matured in control medium showed the most cumulus expansion, followed by those in PF-TCM and PF-WM; those in PF-NCSU showed very slight expansion. A lower (p < 0.05) penetration rate was obtained for oocytes matured in PF-NCSU than in the control medium (59% vs. 81%). In contrast to those in control (96%) and PF-TCM (93%), oocytes in PF-WM (65%) showed a lower male pronuclear formation. Compared to that in the control, a significantly lower (p < 0.05) cleavage rate was also observed for oocytes matured in PF-WM. Similar proportions of embryos developed to the blastocyst stage when oocytes were matured in control (22%) and PF-TCM (13%). These results indicate that pig oocytes can be successfully matured in a protein-free medium with subsequent development to the blastocyst stage.
authors.affiliation: Department of Animal Sciences, University of Missouri-Columbia, 65211, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Abeydeera
authors.forename: W H
authors.initials: WH
authors.lastname: Wang
authors.forename: R S
authors.initials: RS
authors.lastname: Prather
authors.forename: B N
authors.initials: BN
authors.lastname: Day
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000502:physiology; D003470:Culture Media; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D066298:In Vitro Techniques; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D011506:Proteins / Q000502:physiology*; D013552:Swine
chemical_list: D003470:Culture Media; D011506:Proteins