In vitro fertilization and embryo culture in the grey short-tailed opossum, Monodelphis domestica.

In vitro fertilization and early embryo culture was undertaken in the South American marsupial, the grey short-tailed opossum, Monodelphis domestica. Adult females were induced into oestrus by a system of pairing with an unfamiliar male and mature oocytes were recovered from the ovary 15-18 h after mating and placed in pre-warmed modified MEM medium at 33 o C (basal body temperature) or 37 o C. Spermatozoa recovered from the cauda epididymides of adult males were preincubated in medium for 2 h during which time paired spermatozoa separated and initiated hyperactivated motility