Evaluation of dextran for rabbit sperm cryopreservation: Effect on frozen-thawed rabbit sperm quality variables and reproductive performance.

Effects were analysed of dextran supplementation to Me ₂ SO and acetamide rabbit semen freezing extenders on quality characteristics of rabbit spermatozoa and reproductive performance. The final concentration of cryoprotectants in pooled semen samples was 12.4 % Me ₂ SO for the A extenders, 10.7 % Me ₂ SO and 2.9 % acetamide for the D extenders and 8.9 % Me ₂ SO and 2.9 % acetamide in F extenders, with a supplementation of 1.7 % sucrose in all cases. There was not inclusion of dextran in the A0, D0, F0; while 5 % dextran was included in A5, D5, F5 and 10 % dextran in A10, D10 and F10 extenders. Sperm motility and viability rates were similar with use of the different extenders. Acrosome integrity after the freeze-thawing processes, however, was markedly greater when there was dextran supplementation of D and F extenders. Prolificacy was affected by extender composition. When there was artificial insemination (AI) using semen cryopreserved in the A extenders, number of kits born was similar to when there was AI with fresh semen when there was inclusion of 5% dextran for cryopreservation, while there was no effect on prolificacy when there was cryopreservation of semen using the D and F extenders. In conclusion, dextran supplementation of extenders containing Me ₂ SO and acetamide resulted in greater acrosome integrity. Furthermore, when there was AI using sperm preserved in cryo-diluents containing an intermediate concentration of Me ₂ SO, combined with inclusion of 5 % dextran, there was a marked beneficial effect on rabbit doe reproductive performance.
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