Effect of Selenium plus Vitamin E or Vitamin C Alone on in Vivo Fertility, Viability, Freezability and Culture of Embryos in Rabbits

In vivo fertility and embryos viability after cryopreservation is essential for the success of assisted reproductive techniques. The aim of this study was to investigate the impact of vitamin E (VE) +selenium (Se) or vitamin C (VC, as ascorbic acid) on in vivo fertility, embryos quality, freezing ability and culture of rabbit embryos. A total of 30 New Zealand White (NZW) rabbit does and 10 NZW fertile bucks were used in this study. Rabbits were kept under the same condition and individually housed in metal cages. Rabbit does were divided into three similar groups, (n=10 each). Does in the 1 st group (G1) were considered as a control group without treatment. Does in the 2 nd (G2) and 3 rd (G3) groups were treated with 1% of VE+Se and 1% VC given in drinking water, respectively, for 15-18 days before mating. At the end of treatment period, experimental does were naturally mated by untreated bucks. After 72 h of mating, three does from each group were slaughtered and embryos were collected by flushing. At the end of pregnancy period, kindling rate (KR) and litter size (LS) and litter weight were recorded at birth and weaning. The recovered embryos from each group were washed, evaluated and preserved by verification method. Post-thawing embryos were in vitro cultured for assessing their ability to develop up to hatched blastocyst stage. Results showed that KR and LS at birth and weaning was higher (P<0.05) in G3 (80%, 9.29 and 8.86) than in G2 (70%, 7.86 and 7.57) and G1 (70%, 7.0 and 6.57), respectively. Average bunny weight at birth and weaning was higher in G2 and G3 than in G1. Embryo recovery rate after collection was not affected by treatment, being 89.3, 87.9 and 83.9, for G1, G2 and G3, respectively. Embryos of G3 showed the highest (P<0.05) percentage (92.3%) of viable embryos after recovery, normal embryos post-verification (95.8%) and hatched embryos (73.9%) post in vitro culture as compared to G1 (84.0, 90.5 and 52.6%, respectively). The corresponding percentages of embryos of G2 did not differ significantly from those in G1 and G3, being 86.3, 80.0 and 55.0%, respectively. In conclusion supplementing drinking water of rabbit does with 1% ascorbic acid within 15 days pre-conception is recommended to improve litter size and litter weight. Moreover it improves rabbit’s embryos quality embryos.