342 DEVELOPMENT OF PIG OOCYTES MATURED AND FERTILIZED IN CHEMICALLY DEFINED MEDIUM CONTAINING PVA, PVP, AND PFF

Abstract

This study was conducted to develop a serum-free, defined medium for IVM of pig oocytes. TCM-199 with supplemented with polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and porcine follicular fluid (pFF) were used as basal medium. The effects of the these additives on the rates of maturity and development during in vitro fertilization and in vitro culture were examined and subsequently considered as possibile substitutes for bovine serum albumin (BSA). In an experiment that contained nine replicates, pig oocytes from abattoir-derived ovaries were matured in TCM-199 containing pyruvic acid, gentamycin, L-cysteine, ²-estradiol, and FSH, and supplemented with 0.1% PVA, 0.1% PVP, 10% pFF, or 0.1% BSA (control) for 44 h at 39°C, 5% CO₂. Fertilized oocytes were cultured in glucose-free NCSU 23 supplemented with 5 mM sodium pyruvate, 0.5 mM sodium lactate, and the same indicated supplements for 2 days. Maturation, fertilization, and morula and blastocyst formation were examined at 44 h after IVM and at 12, 48, and 120 h after IVF, respectively. Morphology of oocytes and cleaved cells was desplayed by staining with Hoechst 33342. Maturation rates of pig oocytes in IVM media containing PVA (82.4%), pFF (89.4%), or BSA (90.0%) were significantly higher (P < 0.05) than that with PVP (78.6%). Cleavage rates after IVF with PVP (64%) was significantly lower (P < 0.05) than those in PVA (73%), pFF (77%), or BSA (73%) supplements. In vitro development rates to morulae and blastocysts with PVP (54%) were also significantly lower (P < 0.05) than those with the supplements of PVA (63%), pFF (69%), or BSA (65%). In comparison of maturation and fertilization rates of pig oocytes in each of the supplements, the maturity rates with PVA (82.4%), pFF (89.4%), or BSA (90.0%) were significantly lower (P < 0.05) than that with PVP (72.4%) and the fertilization rates with pFF (87.1%) or BSA (89.1%) were significantly higher (P < 0.05) than those with PVA (78.0%) or PVP (70.6%). It may be concluded that PVA and pFF can be substituted for BSA in medium for culturing pig oocytes, and that PVP would not be an acceptable substitute for BSA.