Decrease In Docosahexaenoic Acid Research Articles

Effects of Palm Oil Diet on 4, 7, 10, 13,16-Docosapentaenoic Acid Content of Blood Plasma, Red Cells, and Liver and Muscle Lipids in Rats

The effects of palm oil diets on tissue lipids of rats were studied. Four groups of male Sprague-Dawley rats (4wk old) were maintained on diets containing (10% by weight) physically refined palm oil (PRPO), chemically refined palm oil (CRPO), soybean oil (SO), or canola oil (CO) for two months. Both PRPO and CRPO diets resulted in the appearance of 4, 7, 10, 13,16-docosapentaenoic acid (22:5n-6) in blood plasma, red cells, and liver and muscle lipids, while SO and CO diets did not. This fatty acid was principally found in the phospholipid fraction, such as phosphatidylcholine and phosphatidylethanolamine. The increase of 22:5(n-6) compensated for the decrease of docosahexaenoic acid (DHA; 22:6n-3). The results suggest that diet containing only palm oil as a fat source has a high potential of causing α-linolenic acid deficiency in rats.

The effect of plasma on platelet function in hypercholesterolemic rabbits and the changes in fatty acid composition of the plasma

Rabbits were fed with 1% cholesterol-containing standard diet for 1 to 3 months. The arachidonic acid (AA)-induced aggregation of the platelet-rich plasma (PRP) of the control rabbits was accelerated by substitution of hypercholesterolemic plasma. The incorporation of C-AA into thromboxane B 2 in platelets was increased approximately 1.6 times with PRP and 1.2 times with the washed platelet suspension (WPS) in hypercholesterolemic rabbits as compared with those of the control. Analysis of the fatty acid compositions of phospholipids and total lipids of hypercholesterolemic rabbits revealed an increase in AA of platelets and plasma, and a decrease in docosahexaenoic acid (DHA) in plasma. The AA/DHA ratio of plasma increased dependently on the period of feeding with the high cholesterol diet, and the increase in the ratio was parallel with the acceleration of platelet aggregation by AA in PRP.

Influence of environmental temperature on mitochondrial membranes

Mitochondrial phospholipids from goldfish lateral line muscle were analysed with respect to polar and apolar groups. Groups of 20 goldfish, acclimated to 5, 20 and 30°C, were used. Temperature-induced shifts of both polar and apolar groups of the mitochondrial phospholipids were observed. The fatty acid composition of mitochondrial phospholipids is characterized by a large amount of polyenoic acids, dominated by docosahexaenoic acid and by octadecadienoic acid. At the higher acclimation temperatures, a significant decrease in docosahexaenoic acid is found. However, the resultant effect of environmental temperature on the degree of unsaturation is small, in contrast to the marked effect on mean chain length. Pronounced changes in the molar ratio of phosphatidylcholine and phosphatidylethanolamine are seen; a decrease in mitochondrial phosphatidylcholine is observed at low acclimation temperature, which is compensated for by a nearly equal increase in phosphatidylethanolamine. The main phospholipids are, apparently, phosphatidylcholine, phosphatidylethanolamine and cardiolipin, comprising 90% of the total pool of 12 species. It is found that the anionic nature of the phospholipids is increased at low acclimation temperatures. We discuss this effect and its probable importance in the stabilization of the surface potential of the mitochondrial membranes.