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 MeSO 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 % MeSO for the A extenders, 10.7 % MeSO and 2.9 % acetamide for the D extenders and 8.9 % MeSO 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 MeSO and acetamide resulted in greater acrosome integrity. Furthermore, when there was AI using sperm preserved in cryo-diluents containing an intermediate concentration of MeSO, combined with inclusion of 5 % dextran, there was a marked beneficial effect on rabbit doe reproductive performance.