Dietary very long chain fatty acids directly influence the ratio of tetracosenoic (24:1) to tetracosanoic (24:0) acids of sphingomyelin in rat liver

Twenty-one groups of weanling male Wistar rats were fed semipurified diets containing 5% (w/w) of different dietary fats. After 2 wk, liver sphingomyelin (SM) fatty acid composition was determined. The ratio of 24:1 to 24:0 in liver SM varied over a tenfold range in response to dietary fat type. Stepwise multiple regression analysis indicated that dietary 24:1, 24:0, and 22:1 were the most significant factors in predicting the 24:1/24:0 ratio of liver SM. The mathematical relation between the dietary fatty acid composition and liver SM 24:1/24:0 was y = 1.88 (24:1) - 1.49 (24:0) + 0.21 (22:1) + 0.01 (18:1) + 0.26, r(2) = 0.95, P < 0.0001. These results were confirmed by a second experiment in which the rats were fed olive oil-based diets supplemented with various fatty acid ethyl esters.