MEPS 168:21-33 (1998)  -  doi:10.3354/meps168021

Origin of the monoene fats in the lipid of midwater fishes: relationship between the lipids of myctophids and those of their prey

Hiroaki Saito*, Masakazu Murata

Laboratory of Lipid Chemistry (Lipid Chemistry Section), National Research Institute of Fisheries Science, Ministry of Agriculture, Forestry and Fisheries, Fuku-ura, Kanazawa-ku, Yokohama-shi 236, Japan

ABSTRACT: The lipid and fatty acid composition of the total lipids in the tissues (whole animal excluding stomach contents) and the stomach contents of 13 myctophid species living in the mesopelagic zone were analyzed. Triacylglycerols (TAG) were the dominant deposit lipids in 10 myctophid species, while wax esters (WE) were found to be the major neutral lipids in 3 non vertically migratory species. Lipids from the myctophid stomach contents were determined to contain mixtures of WE and TAG. Monoenoic acids and alcohols were the major fatty components in both the TAG and the WE of the lipids from the tissues and stomach contents of all of the specimens examined. Lipid classes in the stomach contents originating from prey were different from those in myctophid tissues, but the level of monoenes in stomach content lipids was very similar to those in the tissue lipids. This finding suggests that myctophids may transfer dietary lipids to specific lipid classes, without biosynthetic modification such as carbon chain elongation or desaturation.

KEY WORDS: Myctophidae · Monoene · Deep-sea fish · Food chain · Fish oil · Lipid class · Fatty acid composition · Wax ester · Triacylglycerol · Monoenoic fatty acid

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