title: Effect of incremental levels of sunflower-seed oil in the diet on ruminal lipid metabolism in lactating cows.
abstract: Based on the potential benefits of cis-9, trans-11-conjugated linoleic acid (CLA) for human health there is interest in developing sustainable nutritional strategies for enhancing the concentration of this fatty acid in ruminant-derived foods. Most evidence to date suggests that endogenous synthesis is the major source of cis-9, trans-11 in milk fat and ruminal outflow is limited and largely independent of dietary 18 : 2n-6 supply. Four lactating cows fitted with a rumen cannula were used in a 4 x 4 Latin square with 14 d experimental periods to examine the effects of sunflower-seed oil (SFO) as a source of 18 : 2n-6 on ruminal lipid metabolism. Cows were offered grass silage-based diets supplemented with 0, 250, 500 or 750 g SFO/d. Supplements of SFO had no effect on DM intake, milk fat or protein secretion, but increased linearly (P < 0.01) milk yield and milk lactose output and shifted (P < 0.001) rumen fermentation towards propionate at the expense of acetate. SFO supplements increased linearly (P < 0.05) the flow of 18 : 0, 18 : 1, 18 : 2n-6 and total CLA at the omasum and enhanced ruminal cis-9-18 : 1, 18 : 2n-6 and 18 : 3n-3 metabolism. Flows of all-trans- (Delta4-16) and cis- (Delta9-16) 18 : 1 isomers were elevated, while increases in ruminal CLA outflow were confined to trans-8, trans-10 and geometric 9,11 and 10,12 isomers. It is concluded that supplementing grass silage-based diets with plant oils rich in 18 : 2n-6 enhances ruminal outflow of trans-11-18 : 1 and cis-9, trans-11-CLA in lactating cows.
authors.affiliation: Animal Production Research, MTT Agrifood Research Finland, Jokioinen, Finland. kevin.shingfield@mtt.fi
authors.forename: K J
authors.initials: KJ
authors.lastname: Shingfield
authors.forename: S
authors.initials: S
authors.lastname: Ahvenjärvi
authors.forename: V
authors.initials: V
authors.lastname: Toivonen
authors.forename: A
authors.initials: A
authors.lastname: Vanhatalo
authors.forename: P
authors.initials: P
authors.lastname: Huhtanen
authors.forename: J M
authors.initials: JM
authors.lastname: Griinari
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects*; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005285:Fermentation / Q000187:drug effects; D007774:Lactation / Q000187:drug effects / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects*; D008892:Milk / Q000737:chemistry / Q000187:drug effects; D009851:Omasum / Q000378:metabolism; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology*; D012417:Rumen / Q000378:metabolism*; D000074242:Sunflower Oil
chemical_list: D010938:Plant Oils; D000074242:Sunflower Oil