The effect of dose level of essential fatty acids upon fatty acid composition of the rat liver*

Abstract

Rats were fed various levels of either ethyl linoleate, ethyl arachidonate, or ethyl linolenate. Weight gain, fat-deficiency status, and fatty acid composition of the liver lipids were determined.Dietary linoleate, fed in excess of 1% of calories, maintained good growth and cured fat deficiency. Increasing amounts of dietary linoleate were stored in the liver lipids and converted into fatty acids of the linoleate family—20:4 and 22:4. The concentration of 20:3 was decreased. Dietary arachidonate cured fat deficiency three times more effectively than linoleate. Increasing amounts of dietary arachidonate were stored in liver lipids and converted to 22:5ω6. The level of 20:3 was lowered three times more effectively than when linoleate was fed. No fatty acids of the linolenate family were synthesized from linoleate or arachidonate.Dietary linolenate did not support weight gain as efficiently as did linoleate or arachidonate. Fat-deficiency symptoms could not be cured completely. Increasing amounts of dietary linolenate increased the levels of fatty acids of the linolenate family; linolenic acid was stored, and 20:5, 22:5ω3, and 22:6 were synthesized from linolenate. The level of 20:3 was lowered in the same fashion as when linoleate or arachidonate was fed. Thr level of 20:4 was decreased with increasing amounts of dietary linolenate.