Occurrence of n-Odd-Numbered Monoethylenic Fatty Acids in the Liver Oil of the New Zealand School Shark (Galeorhinus australis MacLeay)

Abstract

INVESTIGATIONS on the minor fatty acid constituents of the liver oil of the New Zealand school shark have resulted in the isolation of the saturated n-odd-numbered acids as well as the iso- and (+)anteiso acids of the C₁₅ and C₁₇ series^1,2. These acids had not previously been found in fish oils, but had been earlier isolated from the depot³ and milk fats⁴ of ruminants. In addition, the occurrence of n-hepta-decanoic acid and of (+)-14-methylhexadecanoic acid in tall oil has been established⁵. The occurrence of n-odd-numbered unsaturated acids in animal depot fats was first recorded in lamb caul fat, from which Δ⁹⁻–heptadecenoic acid was isolated⁶ and the presence of pentadecenoic acid indicated: Δ⁹⁻–heptadecenoic acid has also been obtained from musk-ox fat⁷ and from butterfat⁸. Following the feeding of n-odd-numbered saturated fatty acids, Appel, Böhm, Keil and Schiller⁹ found that the corresponding Δ⁹–monounsaturated acids were deposited in the depot and milk fats of goats and sheep. Apart from the above-mentioned instances, however, n-odd-numbered unsaturated acids have not been isolated from depot fats.