Effects of Dietary Fat Sources on Occurrences of Conjugated Linoleic Acid and trans Fatty Acids in Rumen Contents

  • An, B.K. ;
  • Kang, C.W. ;
  • Izumi, Y. ;
  • Kobayashi, Y. ;
  • Tanaka, K.
  • Received : 2002.02.26
  • Accepted : 2002.07.10
  • Published : 2003.02.01


The effects of dietary sources of C18:2 n-6 or C18:3 n-3 fatty acids on the occurrence of conjugated linoleic acid (CLA) and time-dependent changes of free fatty acid fractions in rumen contents were investigated. Sheep (n=4) fitted with rumen fistula were used in a 44 Latin square design wxith each 14 d period. Sheep were fed one of four diets consisting of grass hay and concentrates in a ratio of 70:30. Dietary treatments were 100% concentrates (served as the control), and concentrates were replaced by safflower seed at 30% (SFS), safflower meal at 18% - safflower oil at 12% (SFO), and safflower meal at 18%-linseed oil at 12% (LNO). At the end of each experimental period, rumen contents from each sheep were collected before feeding and at 1, 3, 6 and 12 h after feeding. The levels of cis-9, trans-11 CLA in free fatty acid fraction were considerably increased in all treated groups relative to the control, but not significantly. The increase in cis-9, trans-11 CLA was slightly higher in SFS and SFO groups than group fed diet containing linseed oil. The level of cis-9, trans-11 CLA in free fatty acid fraction was reached to the maximum value at 1hr after feeding and, thereafter gradually decreased to near the value before feeding. The generation of trans-11 C18:1 was significantly higher in all treated groups than that of control. The level of trans-11 C18:1 was linearly increased after feeding of experimental diets, reaching the maximum value at 3 h. Feeding of diets containing polyunsaturated fats to sheep resulted in a marked increase in the levels of trans-11 C18:1 and a slight increase of CLA in free fatty acid fraction of rumen contents. Our results support that endogenous synthesis of CLA from trans-11 C18:1 may be involved the primary source of CLA in dairy product. (Asian-Aust.


Conjugated Linoleic Acid, Free Fatty Acid Fraction;Polyunsaturated Fat Sources;Rumen Content;Sheep;trans-11 C18:1

Cited by

  1. Occurrence of conjugated linoleic acid in ruminant products and its physiological functions vol.76, pp.4, 2005,
  2. Características quantitativas e qualitativas da carcaça de novilhas alimentadas com diferentes fontes energéticas em dietas à base de cascas de algodão e de soja vol.37, pp.2, 2008,
  3. Enhancement of the conjugated linoleic acid and vitamin A and E contents in goat milk through green fodder feeding vol.62, pp.1, 2009,
  4. Profile of ingested fatty acids and in the duodenal digest of steers fed different diets vol.39, pp.11, 2010,