1999 年 70 巻 6 号 p. 535-541
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 experimental cows was about 3.7 times as much as that of the control cows(18.2±2.8 (×±STD) vs. 4.9±: 1.1mg/g of milk fat). The rate of conversion of ingested C 18: 2n-6 to CLA-1 of milk fat was about 20.2%. The mean CLA-1 content of the serum lipid was O.08±0.01% and O.27±0.03% 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.
