36
F. B. SHORLAND
The marked influence of the dietary fat is again suggested by the
fact that whereas captive tigers and pumas fed on cow and horse flesh
deposit considerable proportions (12-13%) of Ci 8 polyene acids derived
from horse flesh (see Table VIII), the same animals in their natural
habitat, living on sheep and deer with fats of relatively high stearic
acid content, deposit these fats more or less unchanged (149). Pathak
and Trivedi (186) have similarly noted a close resemblance in composition between the depot fats of the lion, tiger, and panther and
those of the animals on which they feed, including deer, sheep, and
cattle. However, in the lion and panther the proportions of tetra- and
hexadecenoic acids are somewhat higher, and in addition, the panther
fat contains 8.3% of C 2 o-C 22 unsaturated acids. It is of incidental interest
that the glycerides of the panther depot fat followed Hilditch's (3)
even-distribution rule in contrast to the glycerides of the dietary fat
which contain a much higher content of fully saturated glycerides
than that calculated from this rule. Among the fats of Omnivora may
be included those of humans, which are doubtless influenced by the
diet. The human depot fats examined by Cramer and Brown (187),
apart from the presence of more (8.2-10.2%) octadecadienoic acid, corresponded closely to those of rats fed a diet low in fat. The detailed
study of the fatty acid composition of rodent depot fats is confined to
one species—the rat. Details of the composition of the depot fat of this
species and the influence of the dietary fat on its composition have
been earlier described (see Table II). The fatty acid composition of
the depot fats of the mouse and the porcupine are also shown in Table
III. Both the mouse (146) and the rat (81) are shown to have similar
proportions of palmitic acid, 25-30%, to those found in other mammalian depot fats, but tend to have somewhat lower proportions of
stearic acid. The porcupine (146), on the other hand, has a relatively
high content of palmitic acid amounting to 36.3%.
b. Ruminant Depot Fats. The evidence so far indicates the marked
influence of the dietary fat on the composition of the depot fats of
nonruminants (cf. also Table II). In contrast Shorland (188) has
shown that the fats of ruminants are not markedly affected by the
dietary fats and that the unsaturated acids of the diet are wholly or
partially hydrogenated by the rumen microorganisms, leading to the
formation of depot fats which consist largely of palmitic acid, 25-30%,
stearic acid, 10-30%, and oleic acid or isomers together with small
amounts of other mono-, di-, and polyunsaturated acids (189). The
specific occurrence of trans unsaturated acids in ruminants, as earlier
discussed, is related to the hydrogenating mechanisms of the microorganisms in the rumen (cf. Table VIII). The traces of n-odd-numbered
F. B. SHORLAND
The marked influence of the dietary fat is again suggested by the
fact that whereas captive tigers and pumas fed on cow and horse flesh
deposit considerable proportions (12-13%) of Ci 8 polyene acids derived
from horse flesh (see Table VIII), the same animals in their natural
habitat, living on sheep and deer with fats of relatively high stearic
acid content, deposit these fats more or less unchanged (149). Pathak
and Trivedi (186) have similarly noted a close resemblance in composition between the depot fats of the lion, tiger, and panther and
those of the animals on which they feed, including deer, sheep, and
cattle. However, in the lion and panther the proportions of tetra- and
hexadecenoic acids are somewhat higher, and in addition, the panther
fat contains 8.3% of C 2 o-C 22 unsaturated acids. It is of incidental interest
that the glycerides of the panther depot fat followed Hilditch's (3)
even-distribution rule in contrast to the glycerides of the dietary fat
which contain a much higher content of fully saturated glycerides
than that calculated from this rule. Among the fats of Omnivora may
be included those of humans, which are doubtless influenced by the
diet. The human depot fats examined by Cramer and Brown (187),
apart from the presence of more (8.2-10.2%) octadecadienoic acid, corresponded closely to those of rats fed a diet low in fat. The detailed
study of the fatty acid composition of rodent depot fats is confined to
one species—the rat. Details of the composition of the depot fat of this
species and the influence of the dietary fat on its composition have
been earlier described (see Table II). The fatty acid composition of
the depot fats of the mouse and the porcupine are also shown in Table
III. Both the mouse (146) and the rat (81) are shown to have similar
proportions of palmitic acid, 25-30%, to those found in other mammalian depot fats, but tend to have somewhat lower proportions of
stearic acid. The porcupine (146), on the other hand, has a relatively
high content of palmitic acid amounting to 36.3%.
b. Ruminant Depot Fats. The evidence so far indicates the marked
influence of the dietary fat on the composition of the depot fats of
nonruminants (cf. also Table II). In contrast Shorland (188) has
shown that the fats of ruminants are not markedly affected by the
dietary fats and that the unsaturated acids of the diet are wholly or
partially hydrogenated by the rumen microorganisms, leading to the
formation of depot fats which consist largely of palmitic acid, 25-30%,
stearic acid, 10-30%, and oleic acid or isomers together with small
amounts of other mono-, di-, and polyunsaturated acids (189). The
specific occurrence of trans unsaturated acids in ruminants, as earlier
discussed, is related to the hydrogenating mechanisms of the microorganisms in the rumen (cf. Table VIII). The traces of n-odd-numbered