DIETARY GAMMA-LINOLENIC ACID-ENRICHED OIL REDUCES BODY-FAT CONTENT AND INDUCES LIVER-ENZYME ACTIVITIES RELATING TO FATTY-ACID BETA-OXIDATION IN RATS

The objectives of this study were to examine the effects of dietary ga mma-linolenic acid-enriched oil extracted from fungi on rat body compo sition and on the various enzyme activities relating to fat metabolism in the liver. The oil contained 25.3 g gamma-linolenic acid/100 g fat ty acids. The levels of gamma-linolenic acid-enriched oil in the diets were 0, 1.5 and 4%, to give 0, 2.88 and 7.68 g gamma-linolenic acid/k g diet. The control diet contained 8% soybean oil. The rats were given free access to these diets for 4 wk. Body weight gain was less in the delta-linolenic acid oil-fed groups than in the control group, althou gh food intake was similar among the three groups. Absolute and relati ve carcass fat weights were significantly lower in the gamma-linolenic acid oil-fed groups than in the control group. Carcass protein and wa ter contents were not different among the three groups, although value s were slightly greater than controls in gamma-linolenic acid-fed grou ps when expressed relative to body weight. Plasma total cholesterol an d free fatty acid concentrations generally were lower in the gamma-lin olenic acid oil-fed groups than in the control group. In the liver, th ere were no significant differences in activities of malic enzyme and citrate cleavage enzyme among the three groups. However, the activitie s of carnitine palmitoyltransferase and peroxisomal beta-oxidation wer e significantly higher in the gamma-linolenic acid oil-fed groups than in the control group. These results clearly demonstrate that dietary gamma-linolenic acid oil reduces body fat content and facilitates fatt y acid beta-oxidation in the liver.