The reciprocal relationship over time postweaning
between 16:0 and 18:0 plus 18:1 suggests that fatty
acid elongase (which converts 16:0 to 18:0) and fatty
acid desaturase (which converts 18:0 to 18:1) become
more active during the postweaning period. We
detected fatty acid elongase and desaturase activities
in bovine s.c. adipose tissue in slaughter-weight cattle
(St. John et al., 1991; Chang et al., 1992), but we
have no information concerning the postnatal and
early postweaning activities of these enzyme systems.
Subcutaneous adipose tissues from slaughter-weight
Angus and Braford heifers have virtually identical
elongase and desaturase specific activities (St. John et
al., 1991); however, there also were no differences
between these breed-types in fatty acid composition. It
is tempting to hypothesize that the breed-type differences
observed in the present investigation were due
to inherent differences in these enzyme systems.