CLA Isomers in Milk Fat from Cows Fed Diets with High Levels of Unsaturated Fatty Acids
Marius Collomb, Robert Sieber and Ueli Bütikofer
Swiss Federal Research Station for Animal Production and Dairy Products, CH-3003 Berne, Switzerland.
Aim of study:
What sort of CLA isomers were preferentially found in milk fat from cows fed a fodder rich in either oleic, linoleic or
α-linolenic acid ?Daily intake of unsaturated acids (UFA), (g day-1cow-1) Oleic Linoleic α-Linolenic
RAP1 258 85 42
SUN1 80 281 1
SUN1.4 106 375 1
LIN1 59 48 157 LIN1.4 84 68 224
0 5 10 15 20
CD RAP1 SUN1 SUN1.4 LIN1 LIN1.4
mg / g fat
Σ trans,trans Σ cis,trans / trans,cis cis9, trans11
Results
CLA in milk fat (n = 10 per variant) -10 -5 0 5 10
PC 1 -5
0 5 10
PC 2
α-linolenic acid
t12,t14t 11,t13
t6,t8 t9,t11
Linoleic acid t8,t10 t10,t12 t7,t9
Oleic acid
-10 -5 0 5 10
PC 1 -6
-4 -2 0 2 4 6
PC 2
α-Linolenic acid
12,14 c11,t13
t11,c13
Oleic acid
Linoleic acid t10,c12 t8,c10
t7,c9 c9,t11
Principal component (PC) analysis of the daily intake of UFA and theCLA trans,transin milk. PC1 explains 39 % and PC2 28 % of the total variance.
Principal component (PC) analysis of the daily intake of UFA and theCLA cis, trans/trans,cisin milk. PC1 explains 46 % and PC2 35 % of the total variance.
Diet
- Control diet (CD): Hay ad libitum and 15 kg fodder beet - CD + 1kg rapeseed (RAP1)
- CD + 1 kg sunflowerseed (SUN1) - CD + 1.4 kg sunflowerseed (SUN 1.4) - CD + 1 kg linseed (LIN1)
- CD + 1.4 kg linseed (LIN1.4)
Sample choice & analysis: Ten individual milks per variant (total of 60 milks) were analysed after 2 weeks feeding using GC – Ag+HPLC
Positive correlation coefficients between the daily intake of UFA and the concentration of CLA in milk (P<0.001)
t12t14: 0.88 t11t13: 0.89 ct/tc12,14: 0.88 t11c13: 0.76 c11t13: 0.74 t10t12: 0.78
t9t11: 0.58 t8t10: 0.60 t7t9: 0.47 t10c12: 0.89 c9t11: 0.81 t8c10: 0.85 t7c9: 0.74 t7c9: 0.57
α-Linolenic acid Linoleic acid
Oleic acid
U: CD, +: RAP1, V: SUN1, Y: SUN1.4, O: LIN1, X: LIN1.4
Conclusion: CLA t7c9 was found in highest concentrations in milk fat from cows fed a oleic acid-rich diet, CLA t10t12, t9t11, t8t10, t7t9, t10c12, c9t11, t8c10 and t7c9 in milk fat from cows fed a linoleic acid-rich diet and CLA t12t14, t11t13, ct/tc 12,14, t11c13 and c11t13 in milk fat from cows fed a α-linolenic acid-rich diet. These results indicate the principal probable precursors of the CLA isomers.
E-mail: marius.collomb@alp.admin.ch
