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

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

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

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.

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.

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