Role of dietary γ-linolenic acid in liver lipid metabolism in Japanese quail

1. The importance of linoleic acid (18:2n-6) itself and of dietary y-linolenic acid (18:3n-6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g y-linolenic acid/kg, or 20 g linoleic acid/kg to an n-6 EFA-free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets. 2. Liver weight and lipid content in birds fed the 2 and 4 g y-linolenic acid/kg diet were significantly lower than those in birds fed the y-linolenic acid-free diet. However, no significant difference was observed between the y-linolenic acid- and linoleic acid-supplemented diets. 3. In birds fed the 4 g y-linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to y-linolenic acid of approximately 20% of whole body content. 4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of y-linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.