British Journal of Nutrition

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British Journal of Nutrition (2010), 104:56-66 Cambridge University Press
Copyright © The Authors 2010
doi:10.1017/S0007114510000292

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Metabolism and Metabolic Studies

Effect of incremental amounts of fish oil in the diet on ruminal lipid metabolism in growing steers


K. J. Shingfielda1a2 c1, M. R. F. Leea3, D. J. Humphriesa1, N. D. Scollana3, V. Toivonena2, C. K. Reynoldsa1 and D. E. Beevera1a4

a1 Department of Agriculture, Centre for Dairy Research, The University of Reading, Earley Gate, Reading RG6 6AR, UK
a2 Animal Production Research, MTT Agrifood Research Finland, FI-31600 Jokioinen, Finland
a3 Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EB, UK
a4 Richard Keenan and Company, Borris, County Carlow, Republic of Ireland
Article author query
shingfield kj [PubMed]  [Google Scholar]
lee mrf [PubMed]  [Google Scholar]
humphries dj [PubMed]  [Google Scholar]
scollan nd [PubMed]  [Google Scholar]
toivonen v [PubMed]  [Google Scholar]
reynolds ck [PubMed]  [Google Scholar]
beever de [PubMed]  [Google Scholar]

Abstract

Based on the potential benefits to human health, there is interest in developing sustainable nutritional strategies to enhance the concentration of long-chain n-3 fatty acids in ruminant-derived foods. Four Aberdeen Angus steers fitted with rumen and duodenal cannulae were used in a 4 × 4 Latin square experiment with 21 d experimental periods to examine the potential of fish oil (FO) in the diet to enhance the supply of 20 : 5n-3 and 22 : 6n-3 available for absorption in growing cattle. Treatments consisted of total mixed rations based on maize silage fed at a rate of 85 g DM/kg live weight0·75/d containing 0, 8, 16 and 24 g FO/kg diet DM. Supplements of FO reduced linearly (P < 0·01) DM intake and shifted (P < 0·01) rumen fermentation towards propionate at the expense of acetate and butyrate. FO in the diet enhanced linearly (P < 0·05) the flow of trans-16 : 1, trans-18 : 1, trans-18 : 2, 20 : 5n-3 and 22 : 6n-3, and decreased linearly (P < 0·05) 18 : 0 and 18 : 3n-3 at the duodenum. Increases in the flow of trans-18 : 1 were isomer dependent and were determined primarily by higher amounts of trans-11 reaching the duodenum. In conclusion, FO alters ruminal lipid metabolism of growing cattle in a dose-dependent manner consistent with an inhibition of ruminal biohydrogenation, and enhances the amount of long-chain n-3 fatty acids at the duodenum, but the increases are marginal due to extensive biohydrogenation in the rumen.

(Received December 14 2009)

(Revised January 12 2010)

(Accepted January 15 2010)

(Online publication March 23 2010)

Key Words:Biohydrogenation; n-3 Fatty acids; trans-Fatty acids; Conjugated linoleic acid; Fish oil

Correspondence:

c1 Corresponding author: Professor K. J. Shingfield, fax +358 341883661, email kevin.shingfield@mtt.fi

Footnotes

Abbreviations: CLA, conjugated linoleic acid; FAME, fatty acid methyl esters; FO, fish oil; NDF, neutral-detergent fibre; OM, organic matter; VFA, volatile fatty acids


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