Impact of Soy-Lecithin Based Extender on Quality and Fertility of Preserved Rabbit Semen

Abstract

The current study aimed to evaluate the impact of soy lecithin, instead of egg yolk, in extenders on quality and fertility of rabbit semen preserved at 4°C. Six mature New Zealand White rabbits were used for semen collection. Two different concentrations of soybean lecithin; L1 (1% lecithin and 10% egg yolk) and L2 (only 2% lecithin) were compared with L0 (free lecithin Tris-Yolk extender) as a control. Good quality ejaculates (initial motility ≥ 70%) were diluted to four fold with specified extender and preserved for three days at 4°C. Progressive motility and viability were examined in pooled and diluted semen samples. In addition, fertility test was carried out on 98 multiparous rabbit does using one day preserved (4°C) extended semen. Results showed that both lecithin-containing extenders slightly improved rabbit sperm motility. The decline rate in sperm motility by progress of preservation time was decreased in lecithin-based extenders compared to egg-yolk extenders. After one day of storage, the best progressive motility was observed in L1, but with nonsignificant differences. Both 48h and 72h of preservation at 4ºC showed better results (P<0.05) which were obtained for L1 and L2 as compared to L0. Sperm viability did not differ significantly all over the total periods of cold storage. There were no significant differences in pregnancy rates for artificially inseminated does with lecithin supplemented extenders (L1: 61.8% and L2: 60.0%) compared to control (L0: 58.8%). Conclusively, soybean lecithin could be included in rabbit semen extenders as a non-animal origin instead of egg yolk. It maintained motility, viability values of chilled-stored spermatozoa and preserved their fertilizing capacity.