Fatty acid composition of liver lipids of young lambs

Abstract

1. The changes in the lipid compositon of livers from lambs receiving either ewe's milk or a reconstituted low-fat milk powder have been studies during the first 8 d after birth.2. At birth the phospholipid and unesterified fatty acid fractions constituted the major proportion of the liver lipids. In the lambs on the artificial diet the relative concentration of the phospholipid fraction increased and there were corresponding decreases in the relative concentrations of all the other fractions, whereas in the naturally fed lambs the relative concentration of the phospholipids remained similar to that found in the livers at birth.3. In the liver lipids at birth there were only low concentration of the C18polyunsaturated fatty acids, althoughts there were appreciable concentrations of the higher C20and C22polyunsaturated fatty acids.4. After birth there was a large increase in the concentration of the C18polyunsaturated fatty acids in the livers of the lambs on the natural diet and a decrease in the 20:3ω9:20:4ω6 (triene:tetraene) ratio. In the lambs receiving the artificial diet the concentration of the C18polyunsaturated fatty acids and the trience:tetraene ration remained similar to that observed at birth.5. These changes are discussed in relationship to the metabolism of the essential fatty acid in monogastric animals.