A sucrose-DMSO extender for freezing rabbit semen

Abstract

Summary ― The aim of this study was to define a simple extender for freezing rabbit semen from selected males used to inseminate selected does to obtain embryos for an embryo bank. Four experiments were carried out. In the first experiment, freezing extender was defined on the basis of the results of the post-thawing motility rate. Three factors and their interactions were studied: final concentration of dimethyl sulphoxide (DMSO) (1, 1.25, 1.5 and 1.75 M), egg yolk (0% of 10 v/v) and sugar (none, or 0.5 M of glucose, lactose, sucrose, or maltose). The sucrose and 1.75 DMSO improved significantly the post-thawing motility rate (sucrose 1.75 M DMSO extender: 42 ± 3%). In the second experiment, this freezing extender was used to freeze semen from three lines. The post-thawing motility and normal acrosome rates were similar among the lines when the covariates, fresh motility and normal acrosome rates, respectively, were used in the analysis (52 ± 1 and 66 ± 1 %, respectively). In the third experiment, frozen semen from the White New Zealand line (NZ) was tested by morphological normality and viability of embryos recovered. Recovery data from NZ does inseminated with fresh and frozen semen were compared. No significant differences were found in the number of normal embryos obtained per donor doe (8.9 ± 0.5) and in their survival after vitrification (52% of live foetuses at 29 days of gestation). The sucrose-DMSO extender and freezing procedure used in this work can offer satisfactory results to apply in conservation and genetic programmes.

Effect of freezing extender composition and male line on semen traits and reproductive performance in rabbits

“…The post-thaw sperm-quality parameters observed from different extenders used in this study show that when Me 2 SO was used as permeable cryoprotectant, sucrose replacement by egg yolk had no effect in acrosome integrity after freezing, but provided significantly lower postthawing sperm motility and viability. This finding seems to be consistent with those observed by Vicente and Viudes de Castro (1996), who reported a similar sperm motility with or without egg yolk when the extender contained sucrose. The beneficial effects of sugars in the extender on the post-thaw viability of the mammalian sperm have been reported in several studies (Abdelhakeam et al, 1991;Molinia et al, 1994;Vicente and Viudes de Castro, 1996;Woelders et al, 1997;Malo et al, 2010).…”

“…This finding seems to be consistent with those observed by Vicente and Viudes de Castro (1996), who reported a similar sperm motility with or without egg yolk when the extender contained sucrose. The beneficial effects of sugars in the extender on the post-thaw viability of the mammalian sperm have been reported in several studies (Abdelhakeam et al, 1991;Molinia et al, 1994;Vicente and Viudes de Castro, 1996;Woelders et al, 1997;Malo et al, 2010). Our results demonstrated that the extender with Me 2 SO and sucrose, in addition to significantly improving post-thawing sperm motility and viability, enhanced the reproductive parameters, increasing the implantation sites and the fertility rate at birth, decreasing the implantation losses, and consequently, increasing the TB.…”

Rearing management of rabbit males selected by high growth rate: the effect of diet and season on semen characteristics

“…As for the morphological evaluation of sperm, the results observed in the present work were similar to those reported by other authors working with males of the same rabbit line (85% observed by [32]). The percentage of spermatozoa with cytoplasmic droplets was higher than that reported by other authors working with adult males of the same line (11%, [29]) which is probably due to the youth of the animals (since ejaculates from young males frequently have a high percent of sperm with droplets, [33]).…”

“…The motility rate observed in this experiment was lower than the motility rate reported by other authors when working with fresh semen (usually higher than 70% of motile sperm [32,34,35]). This could have been due to the high dilution rate used in this work (dilution 1:50) to measure the motility parameters with the CASA system; [36] observed a pronounced reduction in motility parameters from rabbit spermatozoa when seminal plasma had been diluted more than 30 fold.…”

Cryopreservation of Genetic Diversity in Rabbit Species (Oryctolagus cuniculus)

“…Nowadays, semen freezing is not a reliable or repeatable method yet, and results after AI with rabbit frozen semen are still too inconstant to plan a routine utilization of this technique (Vicente et al, 1996;Moce et al, 2003). Only half of the sampled males can produce semen with freezable quality and approximately 50% of females give birth after insemination of thawed semen with a large variability [15%~80%].…”