PORCINE SPERM VIABILITY, OOCYTE FERTILIZATION AND EMBRYO DEVELOPMENT AFTER STAINING SPERMATOZOA WITH SYBR-14

The objective of these experiments was to determine the efficacy of th e new membrane permeant nucleic acid stain, SYBR-14, for assessing boa r sperm viability and to determine it's effect on fertilization and ea rly embryonic development using the pig as a model. We examined the st aining patterns of SYBR-14 and another vital stain, Hoechst 33342, bot h in combination with the dead cell stain, propidium iodide (PI), to q uantify the proportion of living and dead spermatozoa in ejaculated an d epididymal semen. Flow cytometry analyses of semen from 4 boars reve aled significant differences among boars for the proportion of SYBR-14 -stained spermatozoa in both epididymal and ejaculated samples, but no t for Hoechst 33342 or PI stained spermatozoa. Gilts were inseminated with unstained spermatozoa or spermatozoa stained with 2 levels of SYB R-14 or 2 levels of the reference stain, Hoechst 33342. Embryos recove red at 42 to 48 h postinsemination were morphologically evaluated, and only 4 to 8-cell embryos were continued in culture. Overall, fluoresc ent staining of boar spermatozoa with SYBR-14 or Hoechst 33342 neither affected their ability to fertilize oocytes, nor the developmental co mpetence of the resultant embryos.