M. L. Scott

Prevention of exudative diathesis in chicks by Factor 3 and selenium.

Summary It is shown that exudative diathesis in the chick, produced by vit. E-free Torula yeast diets, is prevented by crude sources and purified fractions of Factor 3. Selenium, recently identified as the integral part of Factor 3, was highly active. Protection was obtained with 10 μg of selenium per 100 g of diet in form of seleno-cystathionine or sodium selenite; 200 μg of elemental selenium also were effective. All 3 forms of the element stimulated growth.

Methionine and Cystine Requirements of Rainbow Trout

Abstract Methionine and cystine requirements of rainbow trout (Salmo gairdneri) were studied by supplementing a 35% protein semipurified basal diet with these amino acids at graded levels in a factorial design. In experiment 1 (initial average weight of fish, 1.5 g), methionirie levels were 0.30, 0.45, and 0.60% of the diet and cystine levels were 0.04, 0.15, 0.30, 0.45, and 0.60%. In experiment 2 (initial average weight of fish, 8.8 g), methionine levels were 0.55, 0.75, and 0.95% and cystine levels were 0.04, 0.08, 0.12, 0.16, 0.24, and 0.32%. Methionine requirement was estimated to be between 0.55 and 0.75% in the presence of adequate dietary cystine and the cystine requirement was about 0.30% with a diet marginally deficient in methionine. The requirement for both sulfur amino acids was, therefore, between 0.85 and 1.05% of the diet or 2.50 and 3.00% of the protein. Molar efficiency of conversion of dietary methionine to cystine was highest (80%) when the diet was deficient in methionine; this efficie...

New Evidence Concerning Mechanisms of Action of Vitamin E and Selenium

Publisher Summary This chapter examines the evidences concerning mechanisms of action of vitamin E and selenium. Hypotheses concerning the mechanisms of action of vitamin E and selenium have been sharply divided between those holding that both of these substances act simply as nonspecific biological antioxidants. It is found that selenium participates in the activity of the glutathione peroxidase of rat erythrocytes and that highly purified glutathione peroxidase contains 4 gram atoms of selenium per mole of enzyme. The glutathione peroxidase levels in livers of selenium-deficient chicks also showed a severe drop, reaching very low levels by the time the chicks were 13–15 clays of age. This drop occurred whether or not the diet contained vitamin E. The lipid peroxidation of washed hepatic mitochondria and microsomes from newly hatched chicks of breeding hens receiving a diet low in vitamin E and selenium was found to be very high. The mitochondria and microsomes from these chicks had very little innate protection against lipid peroxidation.

Effectiveness of Selenium in Prevention of Nutritional Muscular-Dystrophy in the Chick.

Summary Results have been presented which show that whereas supplementation of a dystrophy-producing diet of severely Vit. E-depleted chicks with either 2.5 mg of d-alpha tocopheryl acetate or 1.0 mg of selenium as sodium selenite per kilogram of diet alone has no effect upon dystrophy, supplementation with these amounts of selenium and Vit. E together completely prevents muscular dystrophy. These results indicate therefore, that both selenium and Vit. E are concerned in prevention of nutritional muscular dystrophy in the chick.

Vitamin E in Health and Disease of Poultry

Publisher Summary Vitamin E plays many roles essential to maintenance of health in poultry. The chick is an excellent experimental animal for study of vitamin E because this vitamin is concerned in the normal functioning of many different tissues in the chick and is required for prevention of a number of different deficiency diseases, the development of which depends upon the particular environmental and dietary conditions prevailing during the conduct, of the experiments. The studies with chicks show that in the nutrition of poultry in health arid disease vitamin E has a dual role, acting both as a nonspecific biological antioxidant, and also as a true vitamin in two or more apparently specific roles. Vitamin E has been shown over the past forty years to be important in the nutrition of poultry in health and disease, not only for normal reproduction but also (1) as natures most effective antioxidant for prevention of encephalomalacia; (2) in a specific role, interrelated with the action of selenium, for prevention of exudative diathesis; and (3) in another role, interrelated with both selenium and cystine, for prevention of nutritional muscular dystrophy.

Vitamin K in animal nutrition.

Publisher Summary Vitamin K is an essential metabolite for humans and for all laboratory and farm animals. The dietary vitamin K requirements of animals depend upon many modifying factors. Of the factors modifying the dietary vitamin K requirements, most important is the synthesis of vitamin K by the gastrointestinal microflora of most animals, especially mammals. Coprophagy also plays an important role by providing a more complete absorption of the microbially synthesized vitamins K. Although vitamin K is synthesized in the intestinal tract of chickens, turkeys, and other avian species, it appears too far down the tract to furnish these species with all of the vitamin K needs. Proper vitamin K nutrition in animals depends upon providing sufficient vitamin K to the liver for optimum use by the animal for synthesis of the vitamin K-dependent plasma proteins involved in the blood clotting mechanism and perhaps for synthesis also of other proteins required in metabolism. The vitamin K must be presented to the liver in a form that can be used directly or that can be readily converted to the metabolically active form of the vitamin. In the presence of vitamin K inhibitors, such as dicoumarol, sulfaquinoxaline, warfarin, etc., optimum vitamin K nutrition occurs only with adequate vitamin K levels provided in the proper form in excess of the amounts inhibited by these antimetabolites.

Effect of protein on utilization of vitamin A in the chick.

Summary 1. At a constant level of dietary vit. A, as the dietary protein was increased, vit. A content of the liver and blood serum of the chick decreased. Also in chicks receiving purified diets containing marginal amounts of vit. A and high protein levels. symptoms of vit. A deficiency occurred sooner and mortality was increased as compared to chicks fed diets containing moderate or low amounts of protein. 2. The decreased vit. A liver storage, resulting when the dietary protein was increased, could not be correlated with changes in liver lipids, nor vit. C blood levels. 3. The ataxia, mortality and other symptoms in young vit. A-deficient chicks was neither preceded nor necessarily accompanied by an increased blood uric acid level. A high protein diet produces high blood uric acid levels regardless of amount of vit. A in the diet. 4. Regardless of dietary vit. A level, the tibia bone ash of the chicks fed the high protein diets decreased as compared to that of chicks receiving a moderate level of protein in the diet.

Effect of arginine deficiency on nutritional muscular dystrophy in the chick.

Summary Nutritional muscular dystrophy in the chick did not occur when an arginine deficient diet was fed even though the diet was low in Vit. E and sulfur amino acids. When arginine was included in the basal diet, a high incidence of muscular dystrophy was observed by 5 weeks of age, even when growth was restricted in the chicks receiving adequate arginine by paired feeding with the basal group.

Alterations of methionine to cysteine conversion rates and nutritional muscular dystrophy in chicks.

Summary The effects of methionine-transmethylation metabolites on nutritional muscular dystrophy and methionine to cysteine conversion rates in vitamin E-deficient chicks have been studied. The results show that guanidoacetic acid accelerates the conversion of methionine to cysteine and reduces the severity of nutritional muscular dystrophy, and that creatine, choline and betaine inhibit that conversion and accentuate the dystrophy. Therefore cysteine, not methionine, must be the metabolically active sulfur amino acid in the prevention of nutritional muscular dystrophy in vitamin E-deficient chicks.

Influence of vitamin E and bile compounds on cysteine metabolism in nutritional muscular dystrophy in chicks.

Summary The results of these experiments support the hypothesis that cysteine is the sulfur compound, or the precursor of a compound, involved in the prevention of nutritional muscular dystrophy in the chicken. Dietary cholie acid increases the rate of cysteine to taurine conversion and at the same time accentuates the dystrophy. Taurocholic acid and taurine decrease the rate of cysteine to taurine conversion and also partially alleviate the dystrophy. Vitamin E supplementation greatly reduces the taurine excretion rate, compared to that of the dystrophic chicks fed the basal diet.