High Linoleic Acid Intake and Vitamin E Requirement in Rats

Self Cite

The effect of dietary linoleic acid and selenium on vitamin E requirement has been investigated. Groups of newly hatched, male Peking ducklings were kept for 4 weeks on diets containing increasing amounts of vitamin E (D α-tocopherol acetate). The dietary fat (35 cal%) consisted of lard (low linoleic acid content), tocopherol-free maize oil (high linoleic acid content) or natural maize oil. In addition to D α-tocopherol acetate, some groups received 0.1 mg selenium (Na₂SeO₃) per kg food. Vitamin E deficiency manifested itself by myopathy of all types of muscles. The skeletal muscles showed the typical hyaline degeneration. Necrocalcinosis was found in the muscular tissue of heart, gizzard and intestine. The lard diet needed 13.5 and the tocopherol-free maize oil diet 27 mg vitamin E/kg food to prevent myopathy; this is 86 and 172 mg D α-tocopherol per kg fat, respectively. For the natural maize oil, this requirement was amply covered by its own tocopherol content, while on lard diets all animals died within 3 weeks, showing severe myopathy when extra vitamin E had not been added. The increased vitamin E requirement of the animals on the tocopherol-free maize oil diet could be explained by their lower blood-tocopherol level, as compared with the lard group, at an equal dietary level of vitamin E. Selenium was found to be most effective in preventing myopathy (0.1 mg Se ≧ 20 mg D α-tocopherol acetate). The beneficial effect of selenium could not be explained by an increase of the plasma tocopherol level. Obviously, most animal fats are inadequate in vitamin E, whereas vegetable oils with a high linoleic acid content (sunflower, maize, safflower) must be considered as the natural sources of this vitamin. It is concluded, that a critical dietary E/PUFA ratio (intake of mg D •α-tocopherol, divided by the intake of polyunsaturated fatty acids in g) does not exist.

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effect of Dietary Linoleic Acid and Selenium on the Requirement of Vitamin E in Ducklings

Jager¹

1972

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“…In a previous investigation [7] it was found that rats on a (tocopherolfree) maize oil diet needed more vitamin E to prevent spontaneous haemolysis in vitro, than rats on a lard diet. From the difference in linoleic acid content of the diet and the difference in vitamin E requirement it could be calculated that for each additional gram of dietary linoleic acid, 0.08 mg D-a-tocopheryl acetate would be needed.…”

Section: Introductionmentioning

confidence: 97%

Effect of Dietary Linoleic Acid on Vitamin E Requirement and Fatty Acid Composition of Erythrocyte Lipids in Rats

Jager¹,

Houtsmuller²

1970

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In order to investigate the effect of an increasing linoleic acid content of the diet on vitamin E requirement, young male rats were divided into 4 groups receiving respectively 0.27, 0.98, 3.57 and 12.98% linoleic acid (from mixtures of coconut oil and tocopherol-free safflower oil) in their diets. Each group was subdivided into 6 groups, receiving increasing amounts of D-α-tocopheryl acetate (2.5–23.5 mg) in their food. Spontaneous haemolysis in vitro was used as a criterion for vitamin E requirement. The amount of D-α-tocopheryl acetate needed to prevent haemolysis was 13 mg/kg food for the lowest three doses linoleic acid, the highest dose required 18 mg/kg food. The fatty acid composition of erythrocyte lipids was not influenced by the vitamin E content and only moderately by the linoleic acid content of the diet: a higher level of dietary linoleic acid caused an increase in linoleic acid content of erythrocyte lipids, which was mainly compensated by a decrease in oleic acid content. The group with the lowest dose of vitamin E and the highest dose of linoleic acid showed a significant increase in non-electrolyte (= thiourea) haemolysis time.

“…Thus, opposite to the findings in chicks (35), the vitamin E deficiency did not give rise to CNS symptoms in the rat. The term 'deficient' is justified by comparison to the work of Jager (18) and Jager and Houtsmuller (21), as the present diet contained less than 1 mg of vitamin E per kilogram and Jager showed that 5 mg/kg diet was low enough to induce an 80% in vitro haemolysis. Furthermore, the present finding of lowered gain in weight as a result of deficiency in vitamin E would, according to Jager (19), only occur when the dietary content of vitamin E is lower than 1.5 mg/kg food.…”

Section: Discussionmentioning

confidence: 92%

“…Elimination of vitamin E from sunflower oil was performed essentially as described by Jager (18). Assay of vitamin E was performed according lo Fabianek et al (14).…”

Section: Methodsmentioning

confidence: 99%

The Influence of Vitamin E Deficiency and Combined Deficiency in Vitamin E and Polyunsaturated Fatty Acids on the Biosynthesis and Degradation of Rat Central Nervous System Myelin

Dinesen

Clausen²

1976

The ability to incorporate intracranially injected ¹⁴C-labelled leucine into central nervous system (CNS) myelin was studied in developing rats fed a control diet, a diet deficient in vitamin E and a diet deficient both in vitamin E and polyunsaturated fatty acids. The turnover of radioactivity incorporated into myelin and the distribution of radioactivity between the individual proteins of rat CNS myelin at various stages of the deficiency state was studied. Impaired myelin formation was found in cases of both types of deficiency. The level of incorporated radioactivity was raised by both types of deficiency throughout the experimental period. The mean half life of myelin radioactivity was found higher in combined deficient animals as compared to control and vitamin-E-deficient rats. The distribution of radioactivity between myelinproteins, separated by polyacrylamide gel electrophoresis, appeared identical in the three experimental groups.