title: Dietary α-linolenic acid from flaxseed oil or eicosapentaenoic and docosahexaenoic acids from fish oil differentially alter fatty acid composition and characteristics of fresh and frozen-thawed bull semen.
abstract: Incorporation rates of dietary omega-3 (n-3) fatty acids (FAs) from different sources into bull plasma and sperm and the effects on physiological characteristics of fresh and frozen-thawed semen were determined. Fifteen fertile bulls were assigned to three treatment groups and supplemented for 13 weeks with encapsulated fat: (1) SFA-360 g/d per bull saturated FA; (2) FLX-450 g/d per bull providing 84.2 g/d C18:3n-3 (α-linolenic acid) from flaxseed oil; and (3) FO-450 g/d per bull providing 8.7 g/d C20:5n-3 (eicosapentaenoic acid) and 6.5 g/d C22:6n-3 (docosahexaenoic acid, DHA) from fish oil. Blood samples were taken every 2 weeks and semen was collected weekly. With respect to the FA supplements, the proportion of α-linolenic acid in plasma increased in the FLX bulls, whereas that of DHA was increased in the FO bulls, within 2 weeks. However, changes in the sperm FA fraction were first expressed in the sixth week of supplementation: in the FO and FLX bulls the DHA proportion increased (P < 0.001), whereas that of C22:5n-6 FAs (docosapentaenoic acid [DPA] n-6) decreased (P < 0.001). Sperm motility and progressive motility in fresh semen were higher (P < 0.05), and the fading rate tended to be lower in the FLX than in FO bulls (P < 0.06). Furthermore, sperm motility, progressive motility, and velocity in frozen-thawed semen were higher in FLX than in the other groups (P < 0.008). These findings indicate that the proportion of DHA in sperm can be increased at the expense of DPAn-6 by either FO or FLX supplementation, indicating de novo elongation and desaturation of short- into longer-chain n-3 FAs in testes. Furthermore, the moderate exchange of DHA and DPAn-6 in the FLX group's sperm was associated with changes in the characteristics of both fresh and frozen-thawed semen, suggesting the importance of the ratio between these two FAs for sperm structure and function.
authors.affiliation: Department of Ruminant Science, Institute of Animal Sciences, Volcani Center, Bet-Dagan, Israel. Electronic address: uzim@volcani.agri.gov.il.
authors.forename: Uzi
authors.initials: U
authors.lastname: Moallem
authors.affiliation: Department of Ruminant Science, Institute of Animal Sciences, Volcani Center, Bet-Dagan, Israel; Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Neta
authors.affiliation: SION Artificial Insemination and Breeding Center, Hafetz-Haim, Israel.
authors.forename: Yoel
authors.initials: Y
authors.lastname: Zeron
authors.affiliation: Department of Ruminant Science, Institute of Animal Sciences, Volcani Center, Bet-Dagan, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Zachut
authors.affiliation: Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Zvi
authors.initials: Z
authors.lastname: Roth
mesh_terms: D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000662:veterinary; D004032:Diet; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage; D005227:Fatty Acids / Q000032:analysis* / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005395:Fish Oils / Q000737:chemistry*; D008043:Linseed Oil / Q000737:chemistry*; D008297:Male; D012661:Semen / Q000737:chemistry*; D012662:Semen Preservation / Q000662:veterinary; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000737:chemistry; D017962:alpha-Linolenic Acid / Q000008:administration & dosage
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D008043:Linseed Oil; D015118:Eicosapentaenoic Acid
keywords: Bull-sperm characteristic; Omega-3 FA