HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Peterson, D. G. Articles by Bauman, D. E. Search for Related Content PubMed PubMed Citation Articles by Peterson, D. G. Articles by Bauman, D. E.

Analysis of Variation in cis-9, trans-11 Conjugated Linoleic Acid (CLA) in Milk Fat of Dairy Cows¹

Department of Animal Science Cornell University Ithaca, NY 14853

Corresponding author:
D. E. Bauman; e-mail:
deb6{at}cornell.edu.

Conjugated linoleic acid (CLA) is a fatty acid with numerous putative health benefits and is a natural component of ruminant-derived food products. An intermediate in rumen biohydrogenation is cis-9, trans-11 CLA, the major CLA isomer in milk fat. However, the major source of cis-9, trans-11 CLA in milk is endogenous synthesis by ⁹-desaturase conversion of trans-11 C_18:1, another rumen biohydrogenation intermediate. The desaturase indices serve as a proxy for ⁹-desaturase activity and are calculated from the ratios of fatty acid pairs that represent product/substrate for this enzyme. This study analyzed individual animal variation in milk fat content of cis-9, trans-11 CLA and in desaturase indices in milk fat. Thirty lactating Holstein cows were allocated to one of three treatment groups: one received a standard total mixed ration, one received a diet that produced an elevated milk fat content of CLA, and a third treatment group was alternated between these diets at 3-wk intervals over the 12-wk study. There was a two- to threefold variation among individuals on the same diet for both milk fat content of CLA and desaturase indices in milk fat. This hierarchy was maintained to a large extent over the 12-wk study even in the variable treatment group that alternated between the two diets. Within the variable diet treatment, some animals consistently had a substantial response in milk fat content of CLA to dietary shifts, whereas other cows had little or no response. We conclude that while diet is a major determinant of the CLA content in milk fat, individual animal differences also have a substantial effect. The variation among individuals includes differences related to both rumen biohydrogenation and ⁹-desaturase activity in the mammary gland.

Abbreviation key: CLA = conjugated linoleic acid, ED = extruded full-fat soybean diet treatment, SD = standard diet treatment, VD_E = variable diet treatment when receiving the ED treatment diet, VD_S = variable diet treatment when receiving the SD treatment diet

Key Words: conjugated linoleic acid • milk fat • ⁹-desaturase • variation

This article has been cited by other articles:

				H. Soyeurt, F. Dehareng, P. Mayeres, C. Bertozzi, and N. Gengler Variation of {Delta}9-Desaturase Activity in Dairy Cattle J Dairy Sci, August 1, 2008; 91(8): 3211 - 3224. [Abstract] [Full Text] [PDF]

				A. Schennink, J. M. L. Heck, H. Bovenhuis, M. H. P. W. Visker, H. J. F. van Valenberg, and J. A. M. van Arendonk Milk Fatty Acid Unsaturation: Genetic Parameters and Effects of Stearoyl-CoA Desaturase (SCD1) and Acyl CoA: Diacylglycerol Acyltransferase 1 (DGAT1) J Dairy Sci, May 1, 2008; 91(5): 2135 - 2143. [Abstract] [Full Text] [PDF]

				A. K. G. Kadegowda, L. S. Piperova, and R. A. Erdman Principal Component and Multivariate Analysis of Milk Long-Chain Fatty Acid Composition During Diet-Induced Milk Fat Depression J Dairy Sci, February 1, 2008; 91(2): 749 - 759. [Abstract] [Full Text] [PDF]

				E. Pavan and S. K. Duckett Corn oil supplementation to steers grazing endophyte-free tall fescue. II. Effects on longissimus muscle and subcutaneous adipose fatty acid composition and stearoyl-CoA desaturase activity and expression J Anim Sci, July 1, 2007; 85(7): 1731 - 1740. [Abstract] [Full Text] [PDF]

				H. Soyeurt, P. Dardenne, A. Gillon, C. Croquet, S. Vanderick, P. Mayeres, C. Bertozzi, and N. Gengler Variation in Fatty Acid Contents of Milk and Milk Fat Within and Across Breeds J Dairy Sci, December 1, 2006; 89(12): 4858 - 4865. [Abstract] [Full Text] [PDF]

				K. A. Ellis, G. Innocent, D. Grove-White, P. Cripps, W. G. McLean, C. V. Howard, and M. Mihm Comparing the fatty acid composition of organic and conventional milk. J Dairy Sci, June 1, 2006; 89(6): 1938 - 1950. [Abstract] [Full Text] [PDF]

				C. Reveneau, C. V. D. M. Ribeiro, M. L. Eastridge, N. R. St-Pierre, and J. L. Firkins Processing Whole Cottonseed Moderates Fatty Acid Metabolism and Improves Performance by Dairy Cows J Dairy Sci, December 1, 2005; 88(12): 4342 - 4355. [Abstract] [Full Text] [PDF]

				A. L. Lock, D. E. Bauman, and P. C. Garnsworthy Short Communication: Effect of Production Variables on the Cis-9, Trans-11 Conjugated Linoleic Acid Content of Cows' Milk J Dairy Sci, August 1, 2005; 88(8): 2714 - 2717. [Abstract] [Full Text] [PDF]

				J. A. Kelsey, B. A. Corl, R. J. Collier, and D. E. Bauman The Effect of Breed, Parity, and Stage of Lactation on Conjugated Linoleic Acid (CLA) in Milk Fat from Dairy Cows J Dairy Sci, August 1, 2003; 86(8): 2588 - 2597. [Abstract] [Full Text] [PDF]