Free Access
Reprod. Nutr. Dev.
Volume 42, Number 3, May-June 2002
Page(s) 189 - 196

Reprod. Nutr. Dev. 42 (2002) 189-196
DOI: 10.1051/rnd:2002017

Effect of cooling and freezing, the two first steps of a freezing protocol, on the fertilizing ability of the rabbit sperm

Eva Mocé and José Salvador Vicente

Biotechnology Reproduction Laboratory, Department of Animal Science, Polytechnical University of Valencia, Camino de Vera s/n, 46 071 Valencia, Spain

(Received 22 February 2002; accepted 7 May 2002)

The effect of different phases of a freezing protocol on the fertilising ability of rabbit spermatozoa was evaluated. An extender containing 1.75 M DMSO and 0.05 M sucrose (final concentration) was used to freeze rabbit sperm. In the first experiment, the results obtained with fresh and cooled (5 °C for 45 min) sperm were compared; no differences were observed between fresh and cooled semen for any of the parameters studied: fertility rate (78% vs. 91% for fresh and cooled sperm, respectively), and normal embryos two days after insemination (6.8 vs. 8.5 normal embryos for fresh and cooled sperm). In the second experiment, the results obtained with fresh semen and sperm which had passed the first two steps of a freezing protocol (5 °C for 45 min and -30 °C for 30 min, and thawed at 50 °C for 15 s) were compared; the differences between them were obtained for fertility rate (94% vs. 61% for fresh and frozen sperm, respectively) and normal embryos two days after insemination (7.8 vs. 3.8 fresh and frozen sperm). These observations indicated that the differences in the results obtained with fresh and cryopreserved sperm were produced during the second step of the freezing protocol, and that apparently no toxic effect of DMSO was produced.

Key words: embryo / fertility / freezing / rabbit / sperm

Correspondence and reprints: Eva Mocé

© INRA, EDP Sciences 2002