The effect of varying concentrations of chicken plasma egg yolk and glycerol on the viability of canine sperm following short and long-term preservation

Background

Plasma egg yolk (PEY), due to simple preparation and easier access, could be a suitable alternative to raw egg yolk for preserving canine semen.

Aims

The present study investigated suitable concentrations of PEY and glycerol for preservation of canine semen.

Methods

Semen was collected by digital manipulation (seven replicates from four dogs). Following initial raw semen evaluation, the semen was diluted in a tris-based extender supplemented with varying concentrations of chicken PEY (0, 20, and 40% v/v) and glycerol (3%; v/v). After cooling the specimen to 4°C within 1 h, the specimens were diluted with an equal volume of freezing extender consisting of similar concentrations of chicken PEY and 0 and 7% glycerol to reach the final glycerol concentration of 1.5 and 5% for short-term storage of canine semen. Samples with different concentrations of PEY and 5% glycerol were frozen. The sperm viability parameters including total motility, progressive forward motility, plasma membrane integrity, and live percentage of sperm were assessed following short and long-term storage.

Results

Sperm viability parameters of semen extended in an extender supplemented with 20 or 40% chicken PEY with either 1.5 or 5% glycerol remained superior until 72 h after semen collection compared to the specimen that did not receive any PEY (P<0.05). Post-thaw sperm viability was also greater in samples extended in extender supplemented with either 20 or 40% PEY compared to 0% PEY.

Conclusion

Tris-based extender supplemented with either 20% chicken PEY could be suitable for short and long-term preservation of canine semen.

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

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 24h 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.