Lipid metabolism in the northern pike ( Esox lucius L.)—II. The composition of the total lipids and of the fatty acids isolated from lipid classes and some tissues of the northern pike

Abstract

1. 1. The percentage composition of lipid classes of total lipids from the northern pike ( Esox lucius L.) is given. The total lipids consisted mainly of polar lipids (51%), cholesterol(13%) and triglycerides(27%). 2. 2. The fatty acid composition of these lipid classes was studied. A high concentration of C22:6 was found in polar lipids, diglycerides and cholesterol esters, while C20:5 and C22:5 were the major polyunsaturated fatty acids in triglycerides. The fatty acid spectra of polar lipids and diglycerides showed a strong mutual resemblance. 3. 3. The fatty acid composition of total lipids from liver, muscle, intestine, gills, ovaries and testis was studied. The fatty acid composition of the testis lipids differed considerably from those of lipids isolated from other organs in containing a very high concentration of long chain polyunsaturated fatty acids. The differences in the fatty acid composition of the other tissues were much less pronounced.