In vitro production of cattle-water buffalo (Bos taurus - Bubalus bubalis) hybrid embryos

H.P.S. Kochhar  a1, K.B.C. Appa Rao  a2, A.M. Luciano  a3, S.M. Totey  a2, F. Gandolfi  a3, P.K. Basrur  a1 and W.A. King  a1c1
a1 Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
a2 Embryo Biotechnology Laboratory, National Institute of Immunology, New Delhi, India
a3 Department of Anatomy of Domestic Animals, University of Milan, Milan, Italy


Interspecific hybrid embryos are useful models for the study of maternal-fetal interactions, transmission pattern of species-specific markers and parental contributions to growth and developmental potential of pre-attachment embryos. In an attempt to investigate the possibility of producing hybrid embryos of domestic cattle (Bos taurus) and water buffalo (Bubalus bubalis), cattle oocytes were exposed to buffalo sperm and buffalo oocytes were exposed to cattle sperm and the cleavage rate and the post-fertilisation features of hybrid embryos up to the blastocyst stage were compared with those of buffalo and cattle embryos. The cleavage rate in buffalo oocytes exposed to cattle sperm was low (40.8%), with only 8.8% of these hybrid embryos reaching the blastocyst stage. Cattle oocytes exposed to buffalo sperm showed 86.3% cleavage, while 25.9% of these attained the blastocyst stage. The speed of development of both types of hybrids was intermediate between that of cattle and buffalo embryos, with hatching occurring on day 7.5 in hybrid embryos, day 8-9 in cattle and day 7 in buffalo. The proportions of cells contributing to the trophectoderm and the inner cell mass were closer to those of the maternal species in both types of hybrid embryos. Our results indicate that cattle-water buffalo hybrid embryos produced using interspecies gametes are capable of developing to advanced blastocyst stages and that their in vitro fate, and developmental potential, are influenced by the origin of the oocyte.

(Received September 26 2001)
(Accepted December 17 2001)

Key Words: Embryos; Interspecific hybrids; Maternal influence; Reciprocal fertilisation; Water buffalo.

c1 All correspondence to: Dr W. Allan King, Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1. Tel: +1 (519) 824 4120, ext. 4927. Fax: +1 (519) 767 1450. e-mail: waking@uoguelph.ca