The effects of nonpenetrating cryoprotectants added to TEST-yolk-glycerol extender on the post-thaw motility of ram spermatozoa

The effects of adding five different concentrations of 17 polymeric compounds to TEST-yolk-glycerol extender on ram spermatozoa survival was studied. These were Aquacide (I, II, and III); dextran (0.8–1.6, 1.9, 15–20, 70, and 200–300 kDa); three types of Dri-Sweet; hydroxyethyl starch; methyl-cellulose, polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, and Supercol 912. All the compounds tested except the Dri-Sweet compounds and hydroxyethyl starch significantly ( P < 0.05) decreased percentages of motile cells in unfrozen samples. The use of dextran (0.8–1.6 kDa; hydrolyzed dextran separated by ethanol) and Aquacide II significantly ( P < 0.05) increased post-thaw motility of spermatozoa frozen in pellets. Dextran (15–20 kDa), dextran (0.8–1.6 kDa), Aquacide II, and hydroxyethyl starch significantly ( P < 0.05) increased the percentages of post-thaw motility of ram spermatozoa frozen in the presence of glycerol and egg yolk.