Accumulation and apparent oxidation of cis, trans-18:2 isomers relative to linoleic acid in rats
2001
Chen, Z.Y. | Kwan, K.Y. | Huang, Y.
Dietary cis,trans-18:2 isomers impair desaturation and elongation of linoleic acid (delta9cis,12cis-18:2), but little is known of their proportional partitioning between accumulation and oxidation. The present study was therefore designed to assess the accumulation and apparent oxidation of cis,trans-18:2 isomers compared with that of trans-18:1 isomers and delta9cis,12cis-18:2 in rats. Accumulation is defined as whole-body increase in a fatty acid during a given period (i.e. final body content-initial body content). The apparent oxidation (disappearance) is defined as whole-body utilization of a fatty acid relative to its intake for a given period (intake-excretion-accumulation-longer-chain products)/intakex100). The animals were fed on a diet containing 15% (w/w) partially hydrogenated rapeseed oil with 1.72% energy as cis,trans-18:2 isomers and varying amounts of delta9cis,12cis-18:2. The apparent oxidation of total cis,trans-18:2 isomers (72-76% dietary intake) was greater than that of delta9cis,12cis-18:2 (38-51% dietary intake) but it was similar to that of total trans-18:1 isomers (78-82% dietary intake). Among the four isomers, the apparent oxidation of delta9trans,12trans-18:2 was greater than that of the other isomers including delta9trans,12cis-18:2, delta9cis,12trans-18:2 and delta9cis,13trans-18:2. Accumulation of delta5cis,8cis,11cis,15trans-20:4 and delta5cis,8cis,11cis,14trans-20:4 derived from chain-elongation and desaturation of delta9cis,13trans-18:2 and delta9cis,12trans-18:2 was decreased when the dietary delta9cis,12cis-18:2 supply was increased.
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