Mg Of Α-tocopherol Research Articles

Fish oil supplementation reduces excretion of 2,3-dinor-6-oxo-PGF 1α and the 11-dehydrothromboxane B 2/2,3-dinor-6-oxo-PGF 1α excretion ratio in adult men

Dietary supplementation with a fish oil concentrate (FOC) reduced the endogenous synthesis of prostacyclin (PGI 2), as measured by the excretion of its major urinary catabolite, 2,3-dinor-6-oxo-PGF 1α (PGI 2-M). Thirty-four healthy men (24–57 years old) were given controlled diets and supplements that provided 40% of the energy from fat and a minimum of 22 mg/d of α-tocopherol for two consecutive experimental periods of 10 weeks each. During the experimental periods, the men received capsules containing 15 g/d of a placebo oil (PO) (period 1) or 15 g/d of the FOC (period 2). In addition to the PO or FOC, capsules contained 1 mg of α-tocopherol per g of fat as an antioxidant. The average daily excretion of PGI 2-M during the last week of FOC supplementation (period 2) was 22% less ( P = 0.0001) than at the end of the first period. These results are at variance with those reported in comparable human studies conducted by other investigators during the middle and late 1980s. A 20% reduction ( P = 0.003) in the 11-dehydrothromboxane B 2 to 2,3-dinor-6-oxo-PGF 1α excretion ratio at the end of period 2 in this study demonstrates that a shift of the n-6 to n-3 polyunsaturated fatty acid ratio from 12.5 to 2.3 brings about a substantial modulation of the eicosanoid system.

Requirement of Grass Carp Fingerlings for .ALPHA.-Tocopherol.

This experiment was intended to identify the vitamin E (VE)-deficiency symptoms and to determine the requirement of grass carp Ctenopharyngodon idella for α-tocopherol. For this purpose grass carp fingerlings weighing 4.5g on average were fed diets with various levels of α-tocopherol. Fish fed an α-tocopherol deficient diet showed the so-called 'sekoke disease', a similar symptom to the apparent muscular dystrophy of carp, characterized by a marked loss of flesh in the back, while also revealing high moisture and low protein contents in muscles, and the reduction of α-tocopherol content in hepatopancreas and muscle. Lordsis was also observed in fish fed the α-tocopherol deficient diet. Symptoms such as the apparent muscular dystrophy with or without lordsis started appearing from the 9th week of feeding (the 16th week from the pre-feeding experi-ment). Even though fish fed 5 and 10mg of α-tocopherol showed good growth and feed ef-ficienecy, high incidences of the apparent muscular dystrophy and lordsis were also noted. Taking into consideration the incidence of the apparent muscular dystrophy and lordsis as well as the tissue levels of α-tocopherol, it is suggested that the requirement of grass carp fingerlings for α-tocopherol is about 20mg per 100g diet.

The effect of fish oil supplementation on plasma α-tocopherol, retionol, lipid and lipoprotein levels in normolipidemic subjects

The effects of supplementation with MaxEPA fish oil (FO) on the plasma concentrations of α-tocopherol, retinol, lipids and lipoproteins in young male subjects were studied. Ten normolipidemic adult male volunteers (25–39 y) supplemented their usual Western diets for 6 wk with 18 g MaxEPA FO per d. Blood samples were collected prior to supplementation, after 6 wk of supplementation, and 10 wk following cessation of the supplement. There was a significant increase (21%) in plasma α-tocopherol concentration after 6 wk of FO supplementation which returned to baseline 10 wk after cessation of the supplements. Plasma retinol increased by 14% and plasma triglyceride (TG) concentration decreased by 28% after 6 wk of supplementation. When FO was taken as a supplement to a typical Western diet significant increases in the concentrations of total cholesterol (TC) (7%), low-density-lipoprotein cholesterol (LDL-C) (10%) and high-density-lipoprotein (HDL-C) (10%) in normolipidemic subjects were observed. Despite animal data indicating an increased need for dietary vitamin E with FO supplementation, in this clinical trial, the FO supplement administed in this study increased plasma α-tocopherol. This increase in due to the 1.35 mg of α-tocopherol added by the manufacturer which appears sufficient to maintain plasma vitamin E levels in the presence of increased PUFA intake, at least over a 6 wk period. Retinyl ester content in eight commercial FO products other than MaxEPA ranged from 2 to 2450 μg/g FO, with a mean of 315 μ/g. The α-tocopherol content in 12 other FO capsules available to consumers for over the counter purchase ranged from 18 to 2241 μg/g FO, with a mean of 1025 μg/g. The effects of ingesting FO supplements with a low content of α-tocopherol on the plasma levels of α-tocopherol needs to be further examined.

Roles of Vitamin E in Aquaculture

Aquaculture was first affected by vitamin E problems associated with “Sekoke Disease” in carp fed dried silk worm pupae in Japan. Muscular dystrophy was the most marked clinical symptom and it was shown to be caused by the oxidation of the lipids in the feed. Addition of vitamin E in the diet prevented this disease and later studies showed that Sekoke Disease was related to vitamin E deficiency in the tissue. For carp fingerlings the α-tocopherol dietary requirement was 10 mg/100 g dry diet, for chinook salmon 0.53.0 mg, 25 mg for channel catfish, 17 mg for eel but only 2 mg for rainbow trout. However, these requirements are complicated by other factors such as the presence of selenium as a component of glutathione peroxidase, the level of polyunsaturated fatty acids (PUFA), the growth stage, tissue storage levels of vitamin E and likely the water temperature. In general, addition of 510 mg of α-tocopherol per 100 g of diet provided adequate protection for most cultured fish studied to date. Recently, vitamin E have been shown to be essential in reproduction and enhancement of the immune response in fish, although more detailed research is needed to clarify the mechanism of action of vitamin E in reproduction and immunity. Vitamin E is also important in maintaining the flesh quality of frozen fish.

Mechanisms of Absorption, Transport and Tissue Uptake of RRR-α-Tocopherol and d-γ-Tocopherol in the White Rat

The metabolism of α- and γ-tocopherol was studied in three groups of rats that were fed a modified AIN-76 diet containing normal (NE, 0.2 g α-tocopherol/kg), high (HE, 1.0 g α-tocopherol/kg) or low (LE, <0.02 α-tocopherol/kg) vitamin E for 3 mo. After 1, 2 and 3 d of an oral dose of 20 mg of α-tocopherol, γ-tocopherol or both, the levels of the two vitamers were measured in plasma and tissues and in some cases in isolated microsomal and mitochondrial fractions from liver. Twenty-four hours after an oral dose of 20 mg γ-tocopherol the levels of α-tocopherol in plasma and tissues remained constant and higher levels of γ-tocopherol were found in tissues in which low α-tocopherol levels could be found such as in the LE group. In spite of this, it was enabled to remain there, after 2 and 3 d γ-tocopherol had decreased levels in all tissues. When given in combination with α-tocopherol, the levels of γ-tocopherol were lower than when γ-tocopherol was given alone. Microsomes and mitochondria from livers of LE group bound five and nine times more α-tocopherol than γ-tocopherol in rats dosed with equal amount of α- or γ-tocopherol, respectively. These data indicate that the mechanisms that regulate the metabolism of vitamin E are highly specific for α-tocopherol. Moreover, the relative amount of α-tocopherol determined the levels of γ-tocopherol in tissues. However, the retention of γ-tocopherol in tissues did not depend on the presence of α-tocopherol. This observation may be due to preferential binding of α-tocopherol by soluble proteins and cellular membranes such as those of microsomes and mitochrondria and could well explain why α-tocopherol is the vitamer with more vitamin E potency.

Requirement of Tilapia for .ALPHA.-tocopherol.

Feeding experiments were conducted to investigate the requirement of Tilapia for vitamin E and to see whether or not the vitamin E requirement of Tilapia is increased by elevating dietary lipid levels. No apparent deficiency symptom was induced in fish receiving diets of different levels of α-tocopherol with 5% of lipid, although fish fed with the tocopherol-free diet showed the lowest hepatosomatic index. The addition of more than 5mg of α-tocopherol per 100g diet completely prevented the appearance of this symptom. The concentration of α-tocopherol in the liver of fish receiving the tocopherol-free diet was lowest and increased as dietary tocopherol levels increased. The fish receiving diets containing 10% and 15% fish oil methyl esters without tocopherol began to show low appetite and reduced growth from the 3rd week of feeding and were low in growth and feed conversion efficiency. The supplement of 50mg α-tocopherol to these diets effectively improved these conditions. Elevation of the dietary lipid levels from 5 to 15%. in the diet containing 50mg of α-tocopherol reduced the concentration of α-tocopherol in the whole body. The results obtained in these experiments suggest that 5-10mg of α-tocopherol per 100g of diet containing 5% lipid should provide adequate protection in most practical Tilapia diets. The elevation of dietary lipid levels increased the tocopherol requirement of Tilapia, judging from the growth and mortality.

Effect of micronutrients, antioxidants and related compounds on the mutagenicity of 3,2′-dimethyl-4-aminobiphenyl, a colon and breast carcinogen

The possible antimutagenic effects of butylated hydroxytoluene (BHT), disulfiram, indole-3-carbinol, indole-3-acetonitrile, sodium selenite and α-tocopherol on 3,2′-dimethyl-4-aminobiphenyl-induced mutagenicity were studied using the Ames Salmonella/mammalian microsome assay system with strains TA98 and TA100. All seven compounds were nonmutagenic in both bacterial tester strains. The addition of 50–250 μg of sodium selenite, 5–50 mg of α-tocopherol of 50–250 μg of BHT per plate inhibited DMAB-induced mutagenicity in TA98 and/or TA100. Ethoxyquin, disulfiram and indole-3-carbinol increased DMAB-induced mutagenicity in TA100, whereas these compounds had little or no effect in TA98. Indole-3-acetonitrile had very little effect in either strain.

The relationship between dietary lipid levels and .ALPHA.-tocopherol requirement of rainbow trout.

Feeding experiments were conducted to investigate the relationship between the requirement for tocopherol and dietary lipid levels in rainbow trout, and to see whether the vitamin E deficiency of rainbow trout could be induced by elevating dietary lipid levels. The apparent deficiency symptom was induced for the first time in rainbow trout by feeding them with a diet containing 15% pollock liver oil methyl esters. The fish receiving this diet without tocopherol began to show low appetite and reduced growth ratefrom the 6th week of feeding and were lowest in weight gain. The fish also began to show severe convulsions and to die from the 7th week; 40% of the fish died before the end of the experiment. The addition of 5 mg of α-tocopherol per 100g diet completely prevented the appearance of this syndrome and effectively improved growth to a rate comparable to that of the control group. The tocopherol requirement and the tissue storage of α-tocopherol in rainbow trout were also found to be greatly affected by the degree of unsaturation of the fat in the diet. Judging from the appearance of the apparent deficiency symptoms and the concentration of tocopherol in the livers. around 10 mg of α-tocopherol per 100g of diet containing 15% lipid should provide adequate protection in most practical rainbow trout diets.

Effect of .ALPHA.-tocopherol deficiency on carp-VIII. Dietary lipid levels and .ALPHA.-tocopherol requirement of carp.

A feeding experiment was conducted to investigate the relationship between the α-tocopherol requirement of carp and the dietary levels of unsaturation. The fish receiving the diet without supplement of lipid showed the lowest growth rate, because of a lower caloric content and the absence of essential fatty acids. Addition of 5% methyl esters of pollock liver oil to the diet supplemented with 5mg of α-tocopherol increased the growth rate of fish and feed conversion. However, addition of 10% methyl esters slightly depressed growth and resulted in tocopherol deficiency, judging from the appearance of apparent muscular dystrophy, along with convulsions, and from the α-tocopherol content of hepatopancreas. The fish receiving the diets with methyl esters of Pollock liver oil at more than 10% began to show apparent muscular dystrophy from the 8th week of feeding period and about 67% of the fish were diseased in the group fed on the diet containing 20% lipid also resulted in low growth rate and low feed conversion. These result of feeding clearly indicate that elevated levels of dietary lipid, equivalent to an increase of unsaturation in the diet, increase the requirement of carp for α-tocopherol.

Determination of ?-tocopherol by volumetric or coulometric titration with vanadium(V)

The oxidation of α-tocopherol in conc. solutions of acetic acid by vanadium(V) has been utilized for its quantitative determination. Two procedures were developed. In the first one α-tocopherol is titrated with a standard vanadium(V) solution applying either potentiometric or biamperometric indicating system. Amounts of 2–20 mg were determined with a relative standard deviation of 0.3–2.8% and a relative error of 1.5%; the titration is feasible also in ethanol-H2SO4 solution. In the second method vanadium(V) is electrogenerated from 0.1 M VOSO4 solution in acetic acid and a modified amperometric procedure for end-point detection is employed. Amounts of 0.1–2 mg of α-tocopherol were titrated with a relative standard deviation of 0.7–4.3% and a relative error of 2.5%.

Effect of Vitamins A and E on Lipids in Selected Rat Tissues

To study the effect of vitamins A and E on lipids in selected rat tissues, groups of rats were fed weekly 70, 400 or 1200 IU of vitamin A with or without 10 mg of α-tocopherol. After 12 weeks, analyses were made for liver and plasma cholesterol and liver total lipids and vitamin A. Statistical analysis of group means showed that plasma cholesterol of vitamin E-deficient animals fed 1200 IU of vitamin A was significantly higher than that of corresponding animals fed tocopherol. Feeding tocopherol significantly decreased liver cholesterol in animals fed 400 or 1200 IU of vitamin A. Liver cholesterol of animals fed 400 or 1200 IU of vitamin A with tocopherol was significantly less than that of similar animals fed 70 IU of vitamin A. Total lipids in liver, which were not significantly affected by vitamin A, decreased in animals fed vitamin E with 400 or 1200 IU of vitamin A. The storage of vitamin A was significantly increased by increased intake of dietary vitamin A and by feeding vitamin E.

Minimum Daily Requirement of Rabbits for -Tocopherol

During the past year we have been studying the vitamin E requirement of rabbits for the cure and prevention of nutritional muscle dystrophy. Recently, MacKenzie and McCollum1 reported that the rabbit requires 0.7 to 1.0 mg of α-tocopherol per kg of body weight, but this does not quite agree with our Findings. In our experience, rabbits made dystrophic on the Goetsch-Pappen-heimer diet 13 were cured by the daily oral administration of synthetic dl-α-tocopherol acetate in quantities ranging from 0.18 to 1.0 mg per kg of body weight, with most of the cures resulting from doses of 0.2 to 0.5 mg (as free alcohol).We found that a definite correlation exists between the higher requirements and the total α-tocopherol intake. When animals with an apparently high vitamin E requirement were subjected to a new test on a smaller total tocopherol intake, their requirement dropped to a lower level (values ranging from 0.2 to 0.4 mg per kg). These findings suggest that the higher values, as well as the wider range of var...