Effects of dietary linseed oil and marine oil on lipid peroxidation in monkey liver in vivo and in vitro.

Diets rich in linoleic acid (CO) from corn oil, or in linoleic acid and either alpha-linolenic acid (LO) based on linseed oil or n-3 fatty acids (MO) from menhaden oil were fed to male and female Cynomolgus monkeys for 15 wk. In the liver a 40% reduction of alpha-tocopherol occurred in the MO group relative to the CO and LO groups followed by increased formation of lipofuscin in vivo. A four-fold increase of alpha-tocopherol in the MO diet (MO + E) brought the level in the liver to that found with CO and LO. The increased peroxidation in the MO group in the liver phospholipids was associated with the replacement of 60% of the n-6 fatty acids by n-3 fatty acids from menhaden oil. Similar fatty acid profiles were found in groups fed MO and MO + E, respectively. Compared to the CO fed group, feeding alpha-linolenic acid only resulted in a slight incorporation of n-3 fatty acids in the liver membranes mainly due to a direct incorporation of alpha-linolenic acid. However, in monkeys fed menhaden oil more than 30% of the total fatty acids in the liver phospholipids were n-3 fatty acids. The various diets did not influence the activity of liver catalase (EC 1.11.1.6) nor superoxide dismutase (EC 1.15.1.1), but glutathione-peroxidase activity (EC 1.11.1.9) was higher in monkeys fed the MO diet. The catalase activity in females was 20% higher than in males.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary (n-3) fatty acids affect rat heart, liver and aorta protective enzyme activities and lipid peroxidation.

In a 16-wk study, weanling Wistar rats (32 males and 32 females) were fed a modified AIN-76 diet containing 20% fat with various (n-3) fatty acids. All dietary fats provided the same amount of saturates, monounsaturates, and total essential fatty acids [(n-6) + (n-3)]. The control diet contained lard/corn oil (L/CO). The other diets contained (n-3) fatty acids from linseed oil (LSO), from linseed oil + menhaden oil (LSO + MO) or from menhaden oil (MO). The (n-3) diets reduced total and HDL-cholesterol, particularly in rats fed the MO diet. Platelet thromboxane levels were equally depressed by the LSO and MO diets. Dietary (n-3) fatty acids significantly elevated docosahexaenoic acid in livers and hearts of male and female rats, with females reaching higher levels. This increase was accompanied by reduced arachidonic acid, except for hearts of females in which the major decrease was in linoleic acid. Overall, enzyme activities in the MO-fed group were decreased to the following levels (relative to the activity in the control group): heart Mn superoxide dismutase (SOD), 28%; liver CuZnSOD, 82%; aorta CuZnSOD, 32%. Greater reductions in these enzyme activities were seen in the female rats fed the MO diet compared with male rats. Lipid peroxidation, assessed by urinary, heart and liver thiobarbituric acid reactants, was increased by dietary (n-3) fatty acids (MO greater than LSO + MO greater than LSO greater than L/CO) and was higher in females than in males. These results indicate that enhanced lipid peroxidation occurs with the increased oxidative stress of elevated tissue (n-3) fatty acids accompanied by reduced SOD activity.

Influence of diet on (n-3) and (n-6) fatty acids in monkey erythrocytes.

Cynomolgus monkeys were fed oils high in linoleic acid or with half of the linoleic acid replaced by either (n-3) linolenic acid or marine fatty acids. When the diet contained similar quantities of linoleic and (n-3) linolenic acid, erythrocyte fatty acids maintained a ratio of (n-6) to (n-3) fatty acids of approximately 2:4. Fatty acids from menhaden oil enhanced the incorporation of eicosapentaenoic and docosahexaenoic acids into the monkey erythrocytes, the composition of which was not altered by additional alpha-tocopherol.

The Canadian Nutrient File.

Rapid Calculation of the nutrient content of foods and diets requires a current, easily accessible data base. The Canadian Nutrient File is a computerized information bank containing average values for nutrients in foods available in Canada. For easy accessibility, it contains subfiles for food names, nutrient names, and nutrient amounts. Users of the data should appreciate the limitations of this multi-use file.

The linoleic acid and trans fatty acids of margarines.

Fifty brands of margarine were analysed for cis-polyunsaturated acids by lipoxidase, for trans fatty acid by infared spectroscopy, and for fatty acid composition by gas-liquid chromatography. High concentrations of trans fatty acids tended to be associated with low concentrations of linoleic acid. Later analyses on eight of the brands, respresenting various proportions of linoleic to trans fatty acids, indicated that two of them contained still higher levels of trans fatty acids (greater than 60%) and negligible amounts of linoleic acid. It is proposed that margarine could be a vehicle for the distribution of some dietary linoleic acid and that the level of linoleic acid and the summation of the saturated plus trans fatty acids be known to ascertain nutritional characteristics.

Nutritional properties of poppyseed oil relative to some other oils.

Male Wistar rats were fed a purified basal diet with 20% lard and corn oil (3:1), sunflower oil, poppyseed oil, low-erucic rapeseed oil from Brassica napus, cultivar Tower, or mixtures of these oils, for 1 or 26 weeks. None of the hearts exhibited lipidosis at 1 week. At 26 weeks, the level of serum triglycerides was higher in rats fed the mixture of lard and corn oil than in those fed only vegetable oil, and the incidence of cardiac necrosis and fibrosis was higher in rats fed the rapeseed oil than in the other animals. Cardiac phospholipids in rats fed the rapeseed oil contained an elevated level of omega 3 docosahexaenoic acid, particularly in phosphatidylethanolamine. Poppyseed oil exhibited properties similar to those of sunflower oil, was absorbed as well as olive oil, and appeared to be a promising oil for human consumption.

Nutritional effects of partially hydrogenated low erucic rapeseed oils.

The incidence of cardiac lesions in male rats fed rapeseed oil (Brassica campestris, cultivar "Span") was lower with partially hydrogenated oil (iodine value 78) than withe the liquid oil which had been treated in various ways. Another rapeseed oil (Brassica napus, cultivar "Tower") was similarly improved when hydrogenated to iodine value 76.6, but not at iodine value 97.1, as demonstrated in both Sprague-Dawley and Wistar rats. The improved nutritional quality of hydrogenated oil appeared not to be related to the decreased concentration of linolenic acid, because that fatty acid in linseed oil with or without erucic acid did not increase the incidence of lesions. A relatively high concentration of docosahexaenoic acid in the cardiac fatty acids was observed in adversely affected groups, but a lower concentration was found with the appropriately hydrogenated rapeseed oil.

Studies on long chain cis- and trans-acyl-CoA esters and Acyl-CoA dehydrogenase from rat heart mitochondria.

The beta-oxidation of long chain fatty acids was investigated in a preparation of rat heart mitochondria. The acyl-CoA esters of the cis and trans isomers of delta9-hexadecenoic, delta9-octadecenoic, delta11-eicosenoic, and delta13-docosenoic acids were prepared. Rates of the acyl-CoA reaction were determined with an extract from rat heart mitochondria. The apparent Michaelis constant (Km) and maximum velocity (Vmax) were calculated for each substrate. In general, apparent Vmax values decreased with increasing chain length of the monoenoic substrates. Reduced activity of acyl-CoA dehydrogenase with long chain acyl-CoA esters could have contributed to accumulation of lipids in hearts of rats fed diets containing long chain fatty acids.

Myocardial lipids and nucleotides of rats fed olive oil or rapeseed oil.

After 1 week, the level of myocardial fatty acids was 4 times greater in young rats fed high erucic rapeseed oil than in those fed oliver oil. The proportion of erucic acid was 5.6% in the mitochondrial fraction, 15.1% in the microsomal fraction, and 34.8% in the floating fat fraction. This incorporation of erucic acid into triglycerides of the floating fat was evidence of esterification. The changes in the mitochondrial lipids did not alter the content of adenine nucleotides of the myocardium nor its apparent capacity to oxidize substrates.

Pysiological studies on the recovery of salt tolerance by Staphylococcus aureus after sublethal heating.

Cultures of S. aureus in 100 mM potassium phosphate buffer heated at 52 C for 15 min lost their tolerance to 7.5% NaCl. After incubation in a complex growth medium or in a diluted dialyzed medium in which unheated cells were unable to grow, salt tolerance was regained. Heat injury caused 30% loss of lipid. During recovery, the concentration of C(15) and C(17) fatty acids returned to normal, and there appeared to be an oversynthesis of C(16) and C(18) unsaturated acids. Penicillin abolished the latter reaction without affecting recovery; chloramphenicol did not affect fatty acid oversynthesis but reduced recovery. The K/Na ratio was 12.6 in control cells and 3.4 in injured cells, where it remained during the recovery of salt tolerance. Aspartate uptake was about 10% of the control level after injury and about 35% at recovery. Control cells grew without a lag on subculture, but injured cells which had regained their salt tolerance needed about 2 more h of incubation. Cells recovering with penicillin needed 6 more h, and cells recovering with chloramphenicol did not grow without a prolonged lag. Cells of S. aureus, therefore, may recover their salt tolerance while various membrane functions are still damaged.