Changes in semen quality and sperm lipid composition during freezing in boars

Semen samples were collected from 19 boars of various breeds, frozen and stored in liquid nitrogen. Sperm viability and motility after 1, 4 and 6 h of incubation at 37C were measured and the quantities of total phospholipids, triglycerides and free cholesterol were determined. In comparison with fresh semen, sperm viability and motility were decreased in frozen semen. The total lipid content and phospholipid and triglyceride contents were increased and the free cholesterol content was reduced in frozen spermatozoa in comparison with fresh spermatozoa. Freezing reduced the proportion of polyunsaturated fatty acids and increased the proportion of saturated fatty acids in phospholipids.