Genetic Variation in Fowl Semen Cholesterol and Phospholipid Levels and the Relationships of These Lipids with Fertility of Frozen-Thawed and Fresh Semen

Abstract

We studied the influence of five and six generations of selection for duration of fertility of frozen-thawed fowl semen on spermatozoa and seminal plasma cholesterol and phospholipid levels, their ratios, and their relationships with fertility of frozen-thawed and fresh semen. Males from the selected and control line were used. Cholesterol and phospholipid levels were determined in 2 trials for spermatozoa and in a single trial for seminal plasma per generation.The selected line had significantly (P<.01) higher fertility for both frozen-thawed semen and fresh semen.Spermatozoa cholesterol level, cholesterol to phospholipid ratio, and seminal plasma cholesterol and phospholipid levels were significantly (P<.05) lower in the selected line than in the control line; spermatozoa phospholipid to cholesterol ratio was significantly (P<.05) higher in the selected line but spermatozoa phospholipid level and seminal plasma lipid ratios were not changed significantly (P>.05). The heritability estimates of spermatozoa cholesterol and phospholipid levels ranged from zero to .66 and zero to .81, respectively.The phenotypic correlations of spermatozoa and seminal plasma cholesterol with fertility of frozen-thawed semen were negative as were the phenotypic correlations of seminal plasma cholesterol with fertility of fresh semen.