Comparative studies on the ether-linked lipids of ratfish and shark-III. Distribution of squalene and diacyl glyceryl ethers in the different tissues of deep-sea shark, Dalatias licha.

Abstract

The lipid compositions of the different tissues and gut content of deep-sea shark, Dalatias licha, were determined. In this species, the liver contained 83.4% lipids, which was much larger than that of muscle, ovary and gut content, ranging from 17.3% to 0.8%. The liver and ovary lipids were characterized by high percentages of squalene (40.1%, 20.3%) and diacyl glyceryl ethers (27.8%, 35.7%). On the contrary, the lipids of muscle and gut content contained small amounts of the above types of lipids. Glyceryl ethers of diacyl glyceryl ethers of liver and ovary were very similar in composition: the predominant constituents were 18:1 (52.7%-50.8%) and 20:1 (27.1%-24.7%). In both liver and ovary, the component fatty acids of diacyl glyceryl ethers and triglycerides were also similar in composition, predominantly consisting of monoenes (74.8%-81.3%). Based on the characteristic lipid composition and/or the component glyceryl ethers or fatty acids of diacyl glyceryl ethers and triglycerides, it is suggested that the ovary tissue has directly accumulated the liver lipids for egg development.