The present study was designed to investigate the efficacy of Royal Jelly (RJ) addition in honey-included egg yolk and Tris-citric-glucose with dimethysulfoxide (DMSO) for the extension of New Zealand White (NZW) rabbit buck semen conserved frozen. Fifteen sexually mature NZW rabbit bucks, aged 17 months with average body weight of 3.9 kg, were selected for high quality semen. One hundred and forty hybrid nonporous NZW rabbit does, were used for artificial insemination (20 does per each experimental group).
Semen was collected from rabbit bucks, pooled and diluted with 8 different extenders. Control group had Tris-citric-glucose + DMSO + 20% egg yolk, while the other 7 experimental extenders were based on Tris-citric-glucose with DMSO, 2% pure bee honey and 18% egg yolk which were added to diluents (v/v). Royal jelly (RJ) was added in increasing concentrations of 0,10, 20, 30, 40, 50 and 100 mg/6ml diluents for extenders 1, 2, 3, 4, 5 , 6 and 7, respectively. Evaluations for percentages of progressive motility, dead and abnormal spermatozoa were done immediately after dilution and one month of freezing in liquid nitrogen. Fertilizing ability was evaluated as pregnancy rate and litter size of 20 does inseminated artificially for each extender, which showed ≥ 50% sperm progressive motility after thawing. Extender contained 10 mg RJ/ 6 ml diluent showed the best values for motility, dead and abnormal spermatozoa, also for pregnancy rate and litter size.
Conclusively, the results of the present study proved that the addition of royal jelly in bee honey-included egg yolk based extenders may improve the motility, viability and fertilizing ability of rabbit spermatozoa. However, the effect of RJ on NZW rabbit semen quality and fertility is concentration dependent.