Abstract

FELIPE, Antonio E.. Spatio-temporal characteristics of the preimplantational embryonic development in Mycastor coypus (coypu). Cienc. docencia tecnol. [online]. 2006, n.33, pp.155-172. ISSN 1851-1716.

Myocastor coypus (coypu) is a rodent world-wide used as a skin species. The purpose of the present study was to determine the morphology of the preimplantation embryonic development in Myocastor coypus (coypu). Thirty-three virgin and sexually mature females allotted in 6 family nuclei and 1 male were utilised. The mating program implied the daily colpocytological examination by using standardised routine techniques. Samples for the colpocytological followup were collected from all the animals between 11 and 11:30 hours a.m. The observation of vaginal smears was done directly within 5 minutes of sampling. The controlled mating methodology was used. After the oestrus was established by colpocytology, the female was immediately moved to the male's pen. The embryonic age was determined in days post-coitus (d.p.c.), establishing as day 0 the day when spermatozoa were identified in the vaginal smear. Oocytes and embryos were obtained by flushing from day 0 to 10 post-coitus (p.c.). On day 1 p.c., oocytes predominated whereas on day 2 p.c. zygote were predominant. The cleavage period was from day 3 to day 6 p.c. Morulae were collected from day 6 to 9 p.c., whereas blastocysts were collected in days 8 and 9. From oviduct flushing, embryos in zygote and up to morula with less than 30 cells stage were recovered. Embryos in morula with 30 or more cells and up to blastocyst in growth stage were collected from the flushing of hemiuteri.

Keywords : Preimplantational development; Coypu; Myocastor coypus.

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