I. COMPARATIVE STUDY OF LIPIDS OF SHARK LIVERS. II. COMPARATIVE BIOCHEMICAL STUDY OF SOME GORGONIANS.

Abstract

Diterpenoid compounds, cetyl palmitate and hydrocarbons were examined from eggs of Pseudopterogorgia americana and five samples of Plexaura. Two diterpenoid compounds, mw 304 and 306, were obtained only from P. "REM" St. Croix and P."REM" San Cristobal. The lipids from eggs of Ps. americana contained 45% cetyl palmitate. Cetyl palmitate from lipids of Plexaura samples varied from less than 1% to about 2%.

Comparative study of liver oil of single specimens of five different species of sharks indicated that the total oil contents were 58% to 93%. The squalene content of the liver oils was between 0.29% to 0.95%. Total cholesterol content of the oils varied from 5 to 7%, and their free cholesterol varied from 0.3 to 0.7%. Total P content was nearly the same for all liver oils (0.8%). The phospholipid content varied from about 11 to 14%. The total liver neutral lipid was about the same for all samples (85%). Palmitic and oleic acids were the major component of fatty acids. Together they make up 85 to 100%.

Comparative study of lipids of whitetip reef shark livers derived from an unborn young with that of its mother indicated that both samples contained about the same total oil. The embryo liver oil contained about twice as much as that of the mother liver oil. The total cholesterol content of the mother liver oil was about 5 times as much as that of the embryo liver oil, but the free cholesterol content of the embryo was higher than that of the mother liver oil.

Two hydrocarbon compounds, mw 204 and 220, were isolated from P. "REM" St. Croix. One hydrocarbon, mw 204, was isolated from the other four Plexaura samples.

Relatively small differences were found between the two liver oil samples in terms of their total P content, total phospholipids, total neutral lipids, and their individual phospholipids. The mother liver oil had a higher percentage of the same unsaturated fatty acids than that of the embryo.