| The aim of this study was to explore the effect of washing on the quality of frozen-thawed goat spermatozoa and find out the reasons behind the effect .In this study, semen from 4 Boer bucks was collected using an artificial vagina and was pooled and divided into 3 aliquots, one of them (treatment I) was washed twice, Smins each time, with skim milk-egg-aminomethane-citric-acid and the fluid was removed by centrifugation at 1000r/min between washes. Another aliquot (treatment II ) was centrifuged under the same condition, but no seminal plasma was removed. Last aliquot was treated as normal procedure, without centrifugation and removal of seminal plasma. All 3 aliquots were extended with skim milk-egg-aminomethane-citric-acid and were frozen in straws to -196. The percentages of sperm motility, normal acrosome, recovery and abnormal spermatozoa, survival time of spermatozoa, the concentration of GOT-released and the ability of penetration were investigated respectively .The results attained were as follows:1. In treatment II, the percentages of sperm motility, normal acrosome, recovery, abnormal spermatozoa and the survival time were consequently: 0.367 + 0.032,50.142 + 2.298%, 56.422+2.481%, 16.173+2.187%and 9.517+0.631h. In normal treatment, the date were 0.378+0.031, 51.743+2.272%, 59.068+2.289%, 14.265+2.323% and 9.603+ 0.764h. There were no-significant difference between them (P>0.05). But In treatment I, the date were 0.467+0.041, 57.913+2.609%, 70.431+6.825%, 9.305+2.534% and 9.638+0.847h accordingly. There were a significant difference (P<0.01) between them and that of the normal treatment except the survival time. This result indicated that centrifugation had a no-significant effect on the quality of post-thawed goat spermatozoa, but removal of seminal plasma can improve them significantly.2. TEM. was used to investigate the ultrastructural changes of goat spermatozoa before and after freeing. It was observed that centrifugation gave rise to the lightly swollen of rnembrane of spermatozoa. Before freeing. Removal of plasma had no effect on the ultrstracture before freeing. But after freeing and thawing Pseudoacrosome Reaction wasobserved, acrosome of spermatozoa was damaged badly, But in treatment I, the damage spermatozoa subjected was reduced remarkably. This result might give answer to the improvement of plasma-deprived frozen semen.3. The leakage of GOT into the extra cellular plasma was used as an indicator of sperm cell membrane integrity. After removal of plasma, the concentration of GOT from spermatozoa was increased to 280.8 + 60.8U, 376.08+76.5U and 492.88+93.5U from cooling to post-incubation to post-thawing. But in normal treatment, the date were 209.8 +16.7U, 268.8+ 47.5U, and 259.4+29.4U. There were a significant difference between them(P<0.01), this indicate that the integrity of membrane was changed by removal of seminal plasma.4. The fertilization ability of spermatozoa in different treatment were detected by penetrating the zone-free ova of hamaster. After removal of seminal plasma, the penetration rate was 82.312 + 7.478%. It was significantly higher than that of normal treatment (P<0.01). It shown the removal of seminal plasma from goat semen was beneficial in cryopreservating spermatozoa and could improve the fertilization ability of Boer goat spermatozoa... |
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