title: Cholesterol-to-phospholipid ratio in whole sperm and seminal plasma from fertile stallions and stallions with unexplained subfertility.
abstract: Semen samples were collected from six fertile stallions and seven stallions with unexplained infertility. Percentages of motile sperm (77.5 +/- 11.3 versus 67.5 +/- 12.2, P = 0.2), and progressively motile sperm (70.8 +/- 13.6 versus 60.7 +/- 14.0, P = 0.2) were similar between fertile and subfertile stallions, respectively. Morphologic characteristics in ejaculates of control and affected stallions (% normal: 60.2 +/- 18.2 versus 52.9 +/- 11.3, P = 0.4; % abnormal heads 7.3 +/- 4.8 versus 12.1 +/- 5.0, P = 0.11; and % abnormal acrosomes 1.6 +/- 2.1 versus 3.0 +/- 3.4, P = 0.4) did not differ. After incubation with the calcium ionophore A23187, acrosome reaction rate of sperm from fertile stallions was 96 +/- 2.8% whereas only 2.9 +/- 2.5% of sperm from stallions with unexplained subfertility had acrosome reacted (P < 0.001). Molar amounts of cholesterol and phospholipid in whole sperm and seminal plasma did not differ (P > 0.1) between fertile and subfertile stallions. However, the molar ratio of cholesterol-to-phospholipid was 2.5 times greater in the seminal plasma (P = 0.09) and 1.9 times greater (P = 0.009) in whole sperm of subfertile stallions compared to fertile stallions.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, United States. sbrinsko@cvm.tamu.edu
authors.forename: S P
authors.initials: SP
authors.lastname: Brinsko
authors.forename: C C
authors.initials: CC
authors.lastname: Love
authors.forename: J E
authors.initials: JE
authors.lastname: Bauer
authors.forename: M L
authors.initials: ML
authors.lastname: Macpherson
authors.forename: D D
authors.initials: DD
authors.lastname: Varner
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology; D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D005298:Fertility / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D008297:Male; D010743:Phospholipids / Q000378:metabolism*; D012661:Semen / Q000737:chemistry*; D013094:Spermatozoa / Q000737:chemistry*
chemical_list: D010743:Phospholipids; D002784:Cholesterol