Submitted to: Embryo Transfer Newsletter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 1993
Publication Date: N/A
Interpretive Summary: Attempts to preserve porcine embryos for either short or long term have been inconsistent. Here, we review the history of pig embryo cryopreservation and report on cryopreserving by vitrification. These studies indicate that pig embryos can be successfully croyopreserved by vitrification, based on morphology and subsequent development in vitro. Survival following cryopreservation, however, appears to depend upon embryonic stage following vitrification which may be induced by the high levels of cryoprotectants needed to insure proper development of the vitrified state. Also, survival rates of vitrified, zona intact embryos are similar to those of hatched blastocysts. These results may be significant in terms of the future potential of porcine embryo transfer technology.
Technical Abstract: The current objective was to evaluate the pattern of follicular growth, FSH concentrations and yield of embryos in heifers following superovulation with two FISH preparations reportedly differing widely in LH concentration. In experiment 1, 87 synchronized heifers were superovulated in a 2 x 2 factorial design comparing Folltropin (low LH) with Pluset (ration FISH/LH = 1) administered in single or multiple injections. Type of gonadotrophin affected CL numbers and multiple injections resulted in more grad 3 embryos than single injections. In experiment 2, 34 beef heifers were superovulated as described but blood samples were collected on Days 9, 10, 11 and 12 and ovarian scanning was carried out until 72 hours after the first FISH to count medium and large follicles. There was no evidence of different follicular growth patterns according to number of FISH injections. These data indicate that a single injection of Folltropin or Pluset can result in multiple ovulations, and that the FISH profile is different following single and multiple injections.