Gamal Mehaisen, PhD
Professor of Poultry Physiology
7 Gamaa Street, 12613 Giza, Egypt (email)
The aim of this study was to evaluate the cryoprotective effect of different freezing extenders against
cryopreservation injuries on rabbit sperms of 2 lines selected for hyper-prolificacy (H) and longevity (L).
Ejaculates were collected and pooled from ten sexually mature rabbit bucks per each line. A total number
of 196 pooled semen ejaculates per line were used to evaluate post-thawing semen by 252 artificial
inseminations using White New Zealand rabbit does. Semen was equally divided into 3 volumes and
diluted (1:1) with different TRIS-citric acid based extenders (A, B and C). In extender A, 3 M dimethyl
sulfoxide and 0.1 M sucrose were added as cryoprotectants. For extender B, the sucrose in extender A was
replaced by 20% egg-yolk, and for extender C, the TRIS-based extender was supplemented with 2 M
acetamide and 20% egg-yolk. No interaction effect was detected between rabbit line and semen extender
on studied traits. Moreover, no significant differences were detected between H- and L-lines for all traits
except for prolificacy that was higher in L- line (6.04 vs. 4.37 young born at birth, respectively). However,
freezing semen with extender A and B showed better post-thawing semen quality characteristics, fertility
and prolificacy than frozen semen with extender C. It could be concluded that extenders A and B are
preferable for freezing semen of H- and L-rabbit lines than extender C to obtain higher fertility and
prolificacy. A moderate and interesting relationship was found between acrosomal integrity of frozen
semen and fertility rate. (r=0.17; P=0.04).
n/a