Effect of egg yolk and soybean lecithin on tris-based extender in post-Thaw Ram Semen quality and in vitro fertility [Tris-bazli{dotless} sulandi{dotless}ri{dotless}ci{dotless}larda yumurta sari{dotless}si{dotless} ve soya lesitininin eritme sonrasi{dotless} koç spermasi{dotless}ni{dotless}n kalitesi ve in vitro fertilite üzerine etkisi]

The aim of the current study was to evaluate the effect of egg yolk and different soybean lecithin concentrations on the efficiency of ram semen cryopreservation and to test the fertilizing ability of frozen-thawed ram semen. ejaculates with a thick consistency,rapid wave motion (3-5),and >70% initial motility were pooled. pooled semen were then divided into four groups and diluted at 1/5 (semen/extender) with 1%,3%,6% lecithin (l1,l3 and l6) or 20% egg yolk (ey20) using the two-step dilution method. as expected,the results of the current study showed that both motility and the rates of defective acrosomes in sperm were negatively affected by the cryopreservation procedure (p<0.001). the motility values of at 5°c and post-thawed semen in the ey20 group were significantly higher than those in the l1,l3 and l6 groups (p<0.05). there were no differences in motility rates among the lecithin groups at the dilution,cooling,equilibration or post thawing stages (p>0.05). the results of in vitro fertilization,as assessed by the rate of blastocyst formation,were more successful in the ey20 group than those noted in different lecithin groups. in conclusion,freezing ram semen with an extender containing egg yolk could yield better post-thaw sperm parameters and embryonic development compared to lecithin containing extenders.