Supplementation of tris-based extender with plasma egg yolk of six avian species and camel skim milk for chilled preservation of dromedary camel semen

•Pigeon plasma egg yolk are preferable to domestic chicken, partridge and guinea fowl as cooling protectant in dromedary camel semen.•Tris-based extender supplemented with 20% pigeon plasma egg yolk and 20% camel skim milk is suitable to preserve dromedary camel semen at chilled condition.

The present study was conducted to investigate a suitable source (Expt. 1) and concentration (Expt. 2) of plasma egg yolk (PEY) and concentration of camel skim milk (CSM; Expt. 3) to supplement tris based extender for chilled storage of dromedary camel semen. In Expt. 1, PEY (20%) of six avian species (domestic chicken, domestic duck, Japanese quail, partridge, pigeon and guinea fowl) was added to semen extender. In Expt. 2, different concentrations (0, 10, 20, 30 and 40%) of selected PEY from Expt.1 were added to semen extender. In both Expt. 1 and 2, CSM remained constant (20%). In Expt. 3, semen extender was supplemented with different concentrations of CSM (0, 20, 40, 60 and 80%) while the concentration of PEY remained constant. The sperm viability parameters were assessed at 6, 12 and 24 h following chilled storage. In Expt. 1, progressive forward motility (PFM) of diluted semen supplemented with pigeon PEY was similar to domestic duck and Japanese quail PEYs (P > 0.05) and superior to other PEYs (P < 0.05). In Expt. 2, PFM following the addition of 20% pigeon PEY was similar to 10 and 30% (P > 0.05) and greater than 0 and 40% (P < 0.05). In Expt. 3, total motility, PFM and live percentage of sperm were better in 20% compared to 40, 60 and 80% CSM (P < 0.05). In the last experiment, PFM in 20% was better than 0% CSM (P < 0.05). In conclusion, pigeon PEY at the concentration of 20% and CSM at the concentration of 20% could provide beneficial effect on some of the sperm viability parameters during chilled storage of dromedary camel semen.