| dc.description.abstract |
Fresh spermatozoa from bulls established as ‘good freezers’ and‘poor freezers’ (consistently ≥50% or<20% motile spermatozoa after cryopreservation, respectively)were incubated for 96 h in Tes/Tris-egg yolk or TALP-egg yolkmedia at 37°, 20°, 5° or 0°C. The TALPextender contained 0, 100 or 200 mM glycine betaine (GB) to test thehypothesis that GB would efficiently maintain spermatozoa function duringlong-term incubation. The percentage of motile spermatozoa declined over timein a temperature- and medium-dependent fashion. No spermatozoa were motile by24 h incubation at 37°C or by 72 h incubation at 0°C, andthere were no significant differences in the percentage of motile spermatozoafrom either category of bull when spermatozoa were incubated in any media forless than 24 h. Spermatozoa from poor freezers were significantly more motilethan spermatozoa from good freezers after 96 h at 20° or 5°Cin TALP alone; however, GB at both 100 and 200 mM increased the percentage ofmotile spermatozoa in poor and good freezers and eliminated these differences.Overall, the presence of GB at either 100 or 200 mM significantly improved thepercentage of motile spermatozoa at 20°, 5° and 0°C,but not at 37°C.Extra keywords: bull sperm, osmolyte, semen extender,sperm motility. |
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