Ellis, N.

Kim, E. J.

Lee, Michael R. F.

Scollan, Nigel D.

Tweed, J. K. S.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Milk C18 :1 and Conjugated Linoleic Acid Isomers from Cows Grazed on Perennial Ryegrass, Tall Fescue or Timothy Grass Swards Michael R. F. Lee Institute of Grassland and Environmental Research, UK E. J. Kim Institute of Grassland and Environmental Research, UK N. Ellis Institute of Grassland and Environmental Research, UK J. K. S. Tweed Institute of Grassland and Environmental Research, UK N. D. Scollan Institute of Grassland and Environmental Research, UK Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/15-1/12 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 659　 瞯Grasslands/Rangelands Production Systems ——— Forage Quality ,Conservation and UtilizationMilk C18 :1 and conjugated linoleic acid isomers from cows grazed on perennial ryegrass , tallfescue or timothy grass swardsM .R .F . Lee , E . J . K im , N . Ellis , J .K .S Tweed and N .D . ScollanInstitute o f Grassland and Environmental Research , Plas Gogerddan , Aberystwyth , Ceredigion , UK , SY23 3EB michael .lee ＠ bbsrc .ac .ukKey words : C１８ polyunsaturated fatty acids ,perennial ryegrass ,tall fescue ,timothy ,milk fatIntroduction Previous work at our institute has shown substantial variation in the degree of cell damage during ingestion andmastication of different grasses , resulting in differences in the release rate of nitrogen and lipid into rumen fluid ( Kim et al .２００８ ) . These differences in the release rate of lipid may influence the extent of biohydrogenation in the rumen and consequentlyits intermediates C１８ :１ and conjugated linoleic acid ( CLA ) and their concentration in ruminant products . This studyinvestigated the C１８ biohydrogenation intermediates of milk from cows grazing three contrasting grass species ( perennialryegrass , PRG ; tall fescue , TF ; and timothy , TIM) over two years .Materials and methods The experimental design and statistical analysis were described by Lee et al . (２００８ ) . In short ３ grassgenotypes : PRG , TF and TIM were grazed by １２ multi‐parous Holstein × Friesian dairy cows in a replicate ３ × ３ Latinsquare design over two years (２００５ /０６ ) . Each period consisted of ２ weeks grazing followed by a ３ week rest period . Milk fromthe last two days of each period was sub‐sampled and submitted for fatty acid analysis .Results and Discussion The milk from cows grazing TF had a higher concentration of C１８ :１ trans ４ , ９ , total trans , C１８ :１ cis ９ ,１５ and total cis ( Table １ ) than milk from cows grazing the other grass swards . This maybe related to differences in thebiohydrogenation pathway of C１８ PUFA when cows graze TF as the supply of C１８ PUFA substrate on this diet was lower thanthe other two diets ( Lee et al . ２００８ ) . Year differences were seen for C１８ :１ trans ４ , １３ ＋ １４ , total trans and C１８ :１ cis １５ .Interaction effects were also seen for numerous isomers . CLA content showed no discernable pattern between grass species oryear with interaction effects for all isomers .Table 1 Milk C１８ :１ and CLA isomers (mg/１００ml) f rom cows grazed on three grasses over two years .Perennial Ryegrass Tall fescue Timothy P２００５ ２００６ ２００５ ２００６ ２００５ ２００６ s .e .d G Y G倡 YC１８ :１ trans ４ ０ .３６ ０ .４７ ０ .３８ ０ .５５ ０ .３３ ０ .４６ ０ .０６９ 倡 倡 NS５ ０ .３０ ０ .３４ ０ .３２ ０ .４３ ０ .３１ ０ .４６ ０ .０６４ 倡 报 报６ ＋ ７ ＋ ８ ５ .９０ ６ .１９ ６ .７３ ７ .６５ ６ .００ ５ .９２ ０ .５６３ 倡倡倡 NS 倡９ ９ .２４ ８ .６５ １０ .８ ９ .９０ ９ .２７ ８ .１５ ０ .７７０ 倡倡倡 NS NS１０ ７ .５９ ７ .３８ ９ .１２ ７ .８９ ９ .８４ ７ .８４ １ .１６４ 倡 NS 报１１ １３０ ８７ .３ １３２ １１０ １２５ ９３ .７ １３ .８ 倡 倡 报１２ ７ .１６ ９ .４７ ７ .８１ ８ .９５ ７ .４６ ９ .０４ ０ .６４２ NS 倡 报１３ ＋ １４ １６ .６ ２ .６９ １６ .１ ２ .６９ １９ .２ ２ .６９ ２ .６５９ NS 倡倡倡 NS１６ １１ .７ １３ .１ １２ .４ １２ .７ １２ .３ １１ .３ １ .２２ NS NS NSTotal trans １８９ １３６ １９６ １６０ １９０ １４０ １６ .２ 倡 倡倡 NSC１８ :１ cis ９ ８５６ ８８６ ９７７ ９７６ ８７６ ８１８ ６８ .０ 倡倡倡 NS NS１１ １２ .８ １９ .７ １８ .０ ２３ .２ １５ .０ １８ .０ ２ .４５ 倡倡倡 倡 报１２ ２ .４６ ３ .１５ ２ .７５ ２ .８８ ２ .７０ ３ .０９ ０ .３３０ NS NS NS１３ ２ .１８ ２ .９９ ２ .７６ ２ .３４ ０ .２４ ０ .２２ ０ .３６６ 倡倡倡 NS 倡倡倡１５ ４ .８３ ３ .９４ ５ .６１ ４ .３３ ４ .６０ ２ .８０ ０ .３９４ 倡倡倡 倡倡倡 NSTotal cis ８７８ ９１６ １０１０ １０１０ ９０１ ８４４ ６９ .９ 倡倡倡 NS NStrans １０ cis １２ ０ .２０ ０ .１１ ０ .１３ ０ .１２ ０ .１３ ０ .１１ ０ .０５５ NS 倡 报trans １１ trans １３ １ .９８ １ .４５ １ .８４ １ .６１ １ .３０ ０ .６４ ０ .２９５ 倡 倡倡倡 倡倡倡trans ９ trans １１ １ .０９ １ .５４ １ .１１ １ .５２ １ .０６ ０ .７５ ０ .１６９ 倡倡倡 NS 倡倡倡cis ９ trans １１ ５７ .６ ３９ .３ ５６ .７ ４８ .９ ５７ .３ ３９ .７ ６ .５２ 报 倡 倡Total CLA ６０ .９ ４２ .４ ５９ .８ ５２ .２ ５９ .８ ４１ .２ ６ .７０ 报 倡 倡Conclusion Grass species and year can influence the C１８ :１ and CLA isomers in milk , which may be due to differences inbiohydrogenation pathways induced by differential breakdown properties of the grass species .ReferencesKim et al ２００８ Investigation of the effect of grass species on the release of cell contents during bolus formation . Proceedings o fthe British Society o f Animal Science . In press .Lee , MRF , Ellis , N , Tweed , JKS , Scollan , ND . ２００８ . Milk C１８ polyunsaturated fatty acids from cows grazed on perennialryegrass , tall fescue or timothy grass swards . XXI IGC‐IRC , Hohhot , China , In this meeting .

Milk C18 :1 and Conjugated Linoleic Acid Isomers from Cows Grazed on Perennial Ryegrass, Tall Fescue or Timothy Grass Swards

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Milk C18 :1 and Conjugated Linoleic Acid Isomers from Cows Grazed on Perennial Ryegrass, Tall Fescue or Timothy Grass Swards

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