2001 年 72 巻 3 号 p. 218-222
The relationship between desaturation of fatty acid and conjugated linoleic acid (CLA) accumulation in ruminants body fat was examined. Ten castrated goats were assigned to one of two treatments, maintenance group and full-feed group. After a 90 day feeding trial, subcutaneous fat, perinephric fat, Musculus longissimus thoracis, digesta in rumen and abomasum, Medulla ossium flava in left Ossa metatarsalia, Ossa cruris and Femur were obtained. The unsaturated fatty acid and CLA concentration in subcutaneous fat were significantly higher compared to the perinephric fat, and the values of the full-feed group were higher than those of the maintenance group. The CLA and unsaturated fatty acid concentrations in Medulla ossium flava were the highest in Ossa metatarsalia located on body surface followed by Ossa cruris and Femur. CLA concentration in digesta was low, thus the absorption of CLA from digestive tract was not the only important route for CLA supply to ruminant body fat. A high positive correlation between C17: 1/C17: 0 and CLA/t11-C18:1 was recognized in adipose tissues and Medulla ossium flava. The results agreed with the hypothesis that a greater part of CLA in ruminant adipose tissues was biosynthesized. First, the poly-unsaturated fatty acid in feedstuff is changed into t11-C18:1 by rumen biohydrogenation and then t11-C18:1 is absorbed from digestive tract and accumulated in the adipose tissues before converting into CLA by desaturation.
