PARENT SESSION
DEVELOPMENT OF THE EMBRYO
Harborside C
7:30 AM-10:00 AM

(131) THE EFFECT OF PORCINE OVIDUCTAL FLUID ON IN VITRO DEVELOPMENT TO BLASTOCYST STAGE BY HOMOLOGOUS AND HETEROLOGOUS EMBRYOS.

Stell, Slyvia¹, Ford, Joe², Niaz, Mohammad¹, Diehl, John³, Archibong, Anthony¹, ¹ Dept of Obstetrics and Gynecology, Nashville, TN² USDA Meat Animal Research Center, Clay Center, NE³ Dept of Animal and Veterinary Sciences, Clemson, SC

ABSTRACT- In vitro fertilization rates for aspirated human oocytes are approximately 80 - 90%; however, implantation rates among these embryos are low, probably due to asynchronous transfers of cleavage stage embryos into the uterus. Improvement of in vitro culture conditions for the production of morulae/blastocysts could improve pregnancy rates post embryo transfer (synchronous transfer). As a prelude to testing the embryotrophic efficacy of porcine oviductal fluid (POVF) on higher mammalian embryos (primates included), we studied the embryotrophic effects of POVF on mouse embryo during in vitro cultures. Fluids from the oviducts of cycling sows were harvested via surgically implanted cannulae from pro-estrus to early luteal phase of the estrous cycle and volume determined. RIA was used to determined E₂ and P₄ contents of collected POVFs. POVF collected at the first observed rise in P₄ was used for embryo cultures. In expt. 1, porcine zygotes were cultured in modified Kreb's Ringer buffer (control; KRB) or KRB + POVF (final concentration = 10%). In expt. 2, 2-cell mouse embryos were cultured in Whitten's medium supplemented with CZBt medium containing growth factors (WM-CZBt; control) or WM-CZBt-POVF containing 10% POVF. All embryos were cultured for 5 days. Data on the POVF volume and the concentrations of E₂ and P₄ were analyzed by split plot analysis of variance and the differences among means determined by orthogonal contrasts. Data on percentage blastocyst formation were compared by Chi-square. E₂ concentrations remained maximal during pro-estrus. On the day of detected estrus, concentrations of E₂ declined. P₄ concentrations were below the sensitivity of the assay until 48 hours post estrus. As POVF P₄ subsequently increased, the volume of POVFs decreased. More pig embryos cultured in KRB + POVF (73%) attained blastocyst stage than those cultured in KRB (27%; P<0.05). Similarly, more mouse embryos cultured in WM-CZBt-POVF (70%) attained blastocyst stage than those cultured in WM-CZBt (36%; P<0.05). This study indicates that supplementation of in vitro culture media with POVF supported homologous and heterologous embryos development identically thus; exhibiting a non-species specific embryotrophic effect. (Supported by SCORE Grant 2SO6GMO8037-28)

KEY WORDS: porcine oviductal fluid, homologous embryo, heterologous embryo, ovarian steroids