title: Effect of n-3 fatty acids and α-tocopherol on post-thaw parameters and fatty acid composition of bovine sperm.
abstract: OBJECTIVE
  This study was designed to determine the combined effects of adding source of n-3 fatty acids (FA) and α-tocopherol (vitamin E, VE) to semen extender on freezability and FA composition of Brown Swiss bull sperm.
  
  
  METHODS
  Semen samples were collected from 6 Brown Swiss bulls and pooled. In the first trial, semen was divided into 12 groups including 4 levels of n-3 FA (0, 1, 10, 100 ng ml(-1)) and 3 levels of VE (0. 0.2, 0.4 mM). Motility, viability and fatty acid composition of sperm were measured.
  
  
  RESULTS
  The treatment of 10 ng ml(-1) n-3 FA and 0.4 mM VE had the best post-thaw sperm characteristics (P < 0.01). In the second trial, sperm lipid composition of this treatment and control (without FA and VE) was determined. Supplementing n-3 fatty acids during cryopreservation increased docosahexaenoic acid (DHA) and the ratio of n-3 to n-6 FA in sperm before freezing and after thawing.
  
  
  CONCLUSIONS
  The results suggest that combining the optimal level of n-3 FA (10 ng ml(-1)) with the highest level of VE tested (0.4 mM) in a semen extender changed the membrane lipid composition and improved freezablity of Brown Swiss bull sperm.
authors.affiliation: Department of Animal Science, Faculty of Agricultural Science and Engineering, University of Tehran, POBox# 4111, Karaj, Iran. atowhidi@ut.ac.ir
authors.forename: A
authors.initials: A
authors.lastname: Towhidi
authors.forename: J E
authors.initials: JE
authors.lastname: Parks
mesh_terms: D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000379:methods*; D004281:Docosahexaenoic Acids / Q000032:analysis / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6 / Q000032:analysis / Q000378:metabolism; D008297:Male; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000737:chemistry / Q000187:drug effects*; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D008563:Membrane Lipids; D004281:Docosahexaenoic Acids; D024502:alpha-Tocopherol