Development of In Vitro Produced Buffalo (Bubalus bubalis) Embryos in Relation to Time

The objective of the present study was to examine the developmental rates, and the stage of development in relation to time since fertilization, of in vitro produced buffalo embryos. Buffalo cumulus-oocyte complexes obtained from slaughterhouse ovaries were matured and fertilized in vitro. The fertilized oocytes (n = 248) were then co-cultured with buffalo oviductal epithelial cells and evaluated for the developmental stages on Days 2, 4, 6, 7, 8, 9 and 10 post-insemination. The peak of 4-cell stage embryos was observed on Day 2 (63.7 %), whereas Day 4 was marked by peaks of 6-8-cell stage embryos (20.9%) and 16-cell stage embryos to early morulae (50%). On Days 6, 7, 8, 9, and 10 post-insemination, 49.5, 48.3, 38.3, 33.8 and 33.4% embryos were found to be at morula/compact morula stages, 8.8, 12.5, 25.4, 6.0 and 1.2% at early blastocyst/blastocyst stages, 0, 6.8, 7.2, 15.3 and 2.0% at expanded blastocyst stage and 0, 1.6, 4.8, 19.3 and 38.5% hatching/hatched blastocyst stages, respectively. The peaks of early blastocyst/blastocyst, expanded blastocyst and hatching/hatched blastocyst stages were observed on Days 8, 9 and 10, respectively. The percentages of oocytes which initially became arrested and subsequently degenerated were 3.6, 4.8, 10.4, 14.5, 21.3 and 24.5% on Days 4, 6, 7, 8, 9 and 10 post-insemination, respectively.