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) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal 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 Gómez-Cortés, P. Articles by Hervás, G. Search for Related Content PubMed Articles by Gómez-Cortés, P. Articles by Hervás, G.

Milk Production, Conjugated Linoleic Acid Content, and In Vitro Ruminal Fermentation in Response to High Levels of Soybean Oil in Dairy Ewe Diet

P. Gómez-Cortés^*, P. Frutos, A. R. Mantecón, M. Juárez^*, M. A. de la Fuente^*,1 and G. Hervás

^* Instituto del Frío (CSIC), José Antonio Novais 10, Ciudad Universitaria, s/n 28040 Madrid, Spain
Estación Agrícola Experimental (CSIC), Finca Marzanas, 24346 Grulleros, León, Spain

¹ Corresponding author: mafl{at}if.csic.es

Feeding vegetable oils rich in linoleic acid has been demonstrated to be an effective strategy to enrich milk with conjugated linoleic acid (CLA). However, high amounts of vegetable oil in the diet in free form could adversely affect animal performance, mainly in sheep. The aim of this work was to improve the ewe milk fatty acid profile by increasing potentially healthy acids such as CLA without any detrimental effects on milk production and ruminal fermentation with soybean oil (SBO) diet supplementation. Twenty-four ewes were assigned to 2 treatments and fed 2 diets (control or supplemented with 6% of SBO; 2 lots of 6 animals per treatment) and fed ad libitum for 4 wk. The forage:concentrate ratio was 20:80. Batch cultures of rumen microorganisms were used to study in vitro rumen fermentation. Changes in fatty acid profile were characterized as a reduction in C6:0 to C16:0 at the expense of an increase in C18:0, C18:1 isomers, and CLA concentrations. Proportions of milk CLA and trans-11 C18:1 (vaccenic acid) went from 1.04 to 3.44 and 2.08 to 6.20 g/100 g of total fatty acids, respectively. However, the SBO diet also increased trans-10 C18:1 and other trans C18:1 content. No significant decreases were found in the treatments for dry matter intake and milk production. The notable increases in trans-10, cis-12 and trans-9, cis-11 were not accompanied by fat level decreases in ewe milk. Concerning in vitro ruminal fermentation, no significant differences were found in the extent and rate of gas production, effective degradability, in vitro true digestibility, and volatile fatty acid production. The results demonstrate that dairy sheep milk CLA content can be substantially increased (more than 3-fold) by adding high levels of SBO in the diet as free oil, without any negative effects on animal performance.

Key Words: conjugated linoleic acid • ewe • milk • soybean oil

This article has been cited by other articles:

				P. Gomez-Cortes, A. Bach, P. Luna, M. Juarez, and M. A. de la Fuente Effects of extruded linseed supplementation on n-3 fatty acids and conjugated linoleic acid in milk and cheese from ewes J Dairy Sci, September 1, 2009; 92(9): 4122 - 4134. [Abstract] [Full Text] [PDF]

				P. Gomez-Cortes, P. Frutos, A. R. Mantecon, M. Juarez, M. A. de la Fuente, and G. Hervas Effect of supplementation of grazing dairy ewes with a cereal concentrate on animal performance and milk fatty acid profile J Dairy Sci, August 1, 2009; 92(8): 3964 - 3972. [Abstract] [Full Text] [PDF]

				P. Gomez-Cortes, P. Frutos, A. R. Mantecon, M. Juarez, M. A. de la Fuente, and G. Hervas Addition of Olive Oil to Dairy Ewe Diets: Effect on Milk Fatty Acid Profile and Animal Performance J Dairy Sci, August 1, 2008; 91(8): 3119 - 3127. [Abstract] [Full Text] [PDF]