Abstract:
In Experiment 1, to determine the developmental potential of buffalo oocytesof different qualities, compact cumulus-oocyte complexes (COCs) with anunexpanded cumulus mass, and with homogeneous ooplasm were classified as Grade1 (with 5 layers of cumulus cells) and Grade 2 less than 4 layers of cumuluscells). Grade-3 oocytes were either without cumulus cells or with expandedcumulus mass, and with irregular ooplasm. The oocytes were matured for 24 h at38·5°C, 5% CO<emph type="8">2 in air in maturationmedium (10% fetal bovine serum (FBS) in TCM-199 supplemented with 5µg mL<emph type="7">-1 follicle stimulating hormone-P). Thenuclear maturation and cleavage rates, and the proportion of cleaved embryoswhich developed to morula and blastocyst stage were in the order Grade1>Grade 2>Grade 3 (P < 0·05). ForExperiment 2, the maturation medium consisted of TCM-199 supplemented with oneof the following sera at 10% concentration: (1)buffalo oestrus serum (BOS), (2) superovulated buffaloserum (SBS), (3) fetal bovine serum (FBS) and(4) steer serum (SS). Afterin vitro fertilization (IVF), the oocytes wereco-cultured with buffalo oviductal epithelial cells in TCM-199 containing therespective sera at 10% concentration for the subsequent 9 days. Theextent of cumulus expansion and nuclear maturation were not different amongdifferent groups. The cleavage rates were lower (P <0·05) with FBS than with BOS, SBS and SS. The proportion of cleavedembryos which developed to blastocyst stage was higher(P < 0·05) with SBS than with BOS, FBS and SS.