Conjugated Linoleic Acid Content in Milk Fat of the Cows Fed a Large Amount of Linseed

Abstract

The effect of providing a diet containing a large quantity of linoleic acid (C 18: 2n-6) on the production of cow's milk rich in conjugated linoleic acid was examined using four lactating Holstein cows (mean milk yield: 26.8kg).One group of cows was fed with experimental diet containing linseed and the other group was fed with diet without linseed for a period of 56 days. The control and experimental cows received daily 224g of C 18: 2n-6/head and 308g of C 18: 2n-6/head, respectively. A mean cis-9, trans-11/traps-9, cis-11-octadecadienoic acid (CLA-1) content of the milk fat of the total fatty acids for the control and the experimental cows, respectively. On the other hand, mean trans-11-octadecenoic acid contents of the milk fat and serum lipid increased from 2.2 to 5.4% and from 0.93 to 2.48%, respectively, as a result of feeding the experimental diet.

Impact of a basal diet of hay and fodder beet supplemented with rapeseed, linseed and sunflowerseed on the fatty acid composition of milk fat

“…In our study, the highest concentration of the combined C18:2 t11c15 and C18:2 t9c12 FAs was found in milk fat from cows fed LIN1 or LIN1.4; it was attributed to the high concentration of C18:2 t11c15. The increase in the content of CLAs in milk fat by supplementation of a base diet with linseed was confirmed by Aii et al (1999). Recently, AbuGhazaleh et al (2003) reported a high increase in the content of CLAs in milk fat by supplementation of a fish oil diet with linseed.…”

CLA isomers in milk fat from cows fed diets with high levels of unsaturated fatty acids

“…The strong positive correlations (Table 4) between the daily intakes of (i) oleic acid or linoleic acid and the concentration of the CLA isomer trans-7,cis-9 in milk fat; (ii) linoleic acid and the CLA isomers trans-10,trans-12, trans-9,trans-11, trans-8,trans-10, trans-7,trans-9, trans-10, cis-12, cis-9,trans-11, trans-8,cis-10, and trans-7,cis-9; and (iii) α-linolenic acid and the CLA isomers trans-12,trans-14, trans-11,trans-13, cis,trans/trans,cis-12,14, trans-11,cis-13, and cis-11,trans-13 (Table 4) indicated that these FA (oleic, linoleic, and α-linolenic acids) are probably the main indirect precursors of the above-mentioned CLA. Nevertheless, it is well known, for example, that linoleic and α-linolenic acid are both indirect precursors of the CLA isomer cis-9,trans-11 (55), but the highest concentration of this CLA isomer is generally obtained with linoleic acid-rich diets (14,19).…”