Effect of different diluents and cryoprotectants on the quality of frozen-thawed semen in Gallus gallus.

The effect of different diluents (SB, B26, A8, Virgj-2, UNIIP-6 and LAKE), combined with cryoprotectants (glycerol, methylacetamide, dimethylacetamide and dimethylformamide), on cockerel semen viability, after freezing and thawing, was studied. Semen was collected from sixteen 48-week-old Cobb broiler breeders. At collection, the following parameters were assessed: concentration (sperm * 10 9/ml), motility (%), forward progression rating (0-4 scores), progressive motility (%) and damaged cells (%). The same parameters, except for concentration, were measured on semen that had been subjected to a freezing-thawing procedure. The effect of each diluent combined with the different cryoprotectants was analysed using a general linear model procedure. The percentage of motility after freezing-thawing, ranging from 18.22-21.02, was higher in the samples cryopreserved with SB in combination with all the cryoprotectant. The good performance of the SB diluent has been already observed previously. It would seem that during the freezing process, the diluents SB and Virgj-2, combined with the tested cryoprotectant, provide good cell membrane protection to cockerel spermatozoa packed into 0.25 ml straws.