A COMPARISON OF THE FATTY-ACID COMPOSITION OF TRIACYLGLYCEROLS IN ADIPOSE-TISSUE FROM LIMOUSIN AND JERSEY CATTLE

The fatty acid composition of the triacylglycerol fraction of shoulder fat from Limousin and Jersey yearling heifers, yearling steers, and n on-lactating cows was investigated. Significant breed differences in t he degree of fatty acid saturation were apparent between Jersey and Li mousin cows, but were not observed in the yearlings. Jersey cows had l ess saturated fatty acids than the Limousin. Jersey cows showed an inc reased percentage of monounsaturated fatty acids compared with the Jer sey yearlings. In contrast, the level of monounsaturated fatty acids i n the Limousin cows was the same as in the Limousin yearlings. The cal culated indices of enzyme activities also differed between the breeds. Jersey cows had higher indices of Delta 9-desaturase and elongase act ivities than Limousin. This was also reflected by differences in the r atios of total unsaturated and polyunsaturated to saturated fatty acid s. Breed differences were also observed in the triacylglycerol fatty a cid chain length. In this case, however, yearlings showed significant breed differences that were not detected in the cows. Limousin yearlin gs had more long chain fatty acids (C16 and C18) than the Jersey yearl ings. Limousin yearlings also had a higher elongase activity index tha n their Jersey counterparts. Thus, breed and age affect the fatty acid composition in these cattle.