32
F. B. SHORLAND
elasmobranchs, or more or less evenly distributed throughout the
tissues.
The liver oils of fishes exhibiting a diffuse oil distribution have been
shown by Rapson and co-workers {164, 165) to possess lower iodine
values and smaller amounts of C 20 and C 22 unsaturated acids than the
corresponding liver oils. An extreme example of this phenomenon is
that of the New Zealand groper liver oil (166). Here the head oils
exhibit the usual marine type of fatty acid distribution, while the liver
oils contain high proportions of Ci 6 and Ci 8 unsaturated acids together
with abnormally small amounts (7-9%) of C 20 and especially of C 22
unsaturated acids, which range from 0 to 4%.
Although the fats of marine fishes taken from different parts of the
world generally conform to the average marine type, the limited data
on the liver oils taken from fishes of the Southern Hemisphere suggest
an enhanced content of Ci 8 unsaturated acids together with diminished
amounts of C 20 and C 22 unsaturated acids [cf. Hilditch (3)].
The fairly extensive data on the fats of marine mammals, including
whales and seals, show that the fatty acid composition is generally
similar to that of marine fishes, but the content of Ci 8 unsaturated acids
is somewhat higher, and that of the C 20 and C 22 unsaturated acids
lower. This may be the result of the formation of appreciable amounts
of endogenous fat.
The oils from the blubber and head cavity of the sperm whale differ
from those of other whales in that they consist mainly of esters of
higher aliphatic alcohols. Moreover, the average molecular weight of
the fatty acids, which are largely monoethenoid, is lower (167).
TABLE VII
FATTY ACID COMPOSITION (WEIGHT %) OF THE BODY BLUBBER
OF THE PORPOISE (168)
Source
Adult
Fetus
C 5
13.6
1.2
Saturated
Cl2
3.5
—
Cl4
12.1
14.9
Cl6
4.7
0.6
C 14
4.7
12.3
Cl6
27.2
48.1
Unsaturated
Cl8
16.7
(2.8 H)
15.4
(4.0 H)
C20
10.5
(4.8 H)
7.5
1 (7.4 H)
C22
7.0
(4.9 H)
The head, jaw, and body oils of dolphins and porpoises contain
considerable proportions (up to 25%) of isovaleric acid, which are absent from the organ and liver fats. The fetal blubber fat, in which iso-
F. B. SHORLAND
elasmobranchs, or more or less evenly distributed throughout the
tissues.
The liver oils of fishes exhibiting a diffuse oil distribution have been
shown by Rapson and co-workers {164, 165) to possess lower iodine
values and smaller amounts of C 20 and C 22 unsaturated acids than the
corresponding liver oils. An extreme example of this phenomenon is
that of the New Zealand groper liver oil (166). Here the head oils
exhibit the usual marine type of fatty acid distribution, while the liver
oils contain high proportions of Ci 6 and Ci 8 unsaturated acids together
with abnormally small amounts (7-9%) of C 20 and especially of C 22
unsaturated acids, which range from 0 to 4%.
Although the fats of marine fishes taken from different parts of the
world generally conform to the average marine type, the limited data
on the liver oils taken from fishes of the Southern Hemisphere suggest
an enhanced content of Ci 8 unsaturated acids together with diminished
amounts of C 20 and C 22 unsaturated acids [cf. Hilditch (3)].
The fairly extensive data on the fats of marine mammals, including
whales and seals, show that the fatty acid composition is generally
similar to that of marine fishes, but the content of Ci 8 unsaturated acids
is somewhat higher, and that of the C 20 and C 22 unsaturated acids
lower. This may be the result of the formation of appreciable amounts
of endogenous fat.
The oils from the blubber and head cavity of the sperm whale differ
from those of other whales in that they consist mainly of esters of
higher aliphatic alcohols. Moreover, the average molecular weight of
the fatty acids, which are largely monoethenoid, is lower (167).
TABLE VII
FATTY ACID COMPOSITION (WEIGHT %) OF THE BODY BLUBBER
OF THE PORPOISE (168)
Source
Adult
Fetus
C 5
13.6
1.2
Saturated
Cl2
3.5
—
Cl4
12.1
14.9
Cl6
4.7
0.6
C 14
4.7
12.3
Cl6
27.2
48.1
Unsaturated
Cl8
16.7
(2.8 H)
15.4
(4.0 H)
C20
10.5
(4.8 H)
7.5
1 (7.4 H)
C22
7.0
(4.9 H)
The head, jaw, and body oils of dolphins and porpoises contain
considerable proportions (up to 25%) of isovaleric acid, which are absent from the organ and liver fats. The fetal blubber fat, in which iso-