Bovine and buffalo in vitro embryo production using oocytes derived from abattoir ovaries or collected by transvaginal follicle aspiration

This study was undertaken in order to evaluate the effect of oocyte source (live animals and abattoir ovaries) on subsequent embryo development in buffalo (Bubalus bubalis). Cow ovaries were also collected as oocyte donors for in vitro embryo production (IVEP). Three hundred thirty-eight oocytes were recovered by ovum pick up (OPU, Group A) from 8 pluriparous buffalo cows, while 1127 and 1457 oocytes were aspirated, respectively, from buffalo (Group B) and bovine (Group C) slaughterhouse ovaries. Cumulus enclosed oocytes (COCs) suitable for IVEP were in vitro matured (IVM), fertilized (IVF) and cultured (IVC) to the tight morula (Tm) and blastocyst (B1) stage. Within buffalo species Group A had a higher B1 yield (29.7 % versus 19.9%; P < 0.05) and a lower proportion of embryos arrested at Tm stage (11.1 % versus 22.3%; P < 0.05) than Group B. Within slaughterhouse groups cattle oocytes had a higher cleavage rate (83.9% versus 64.8%; P < 0.05) and yielded 49.2% more blastocysts than buffalo. However, when data are related to the total number of cleaved oocytes, only 13.7% more blastocysts were produced in cattle than in buffalo. In conclusion, in buffalo species the source of oocytes significantly affected post-fertilization embryo development, as demonstrated by the higher B1 yields derived from OPU-derived oocytes. A higher overall IVEP efficiency, mainly related to the higher cleavage rate, was recorded in cattle compared with buffalo when ovaries from an abattoir were used as oocyte donors. (C) 2002 Elsevier Science Inc. All rights reserved.