ABSTRACT
The weaning male Wistar rats were fed diets with 0.2, 2.0 and 5.0 ppm as Na2SeO4 respectively for 7 weeks. On each Se level, rats were divided into groups with or without supplementation of vitamin E and DL-methi-onine (VE-Met) and possible metabolic interactions of VE-Met to dietary Se at different levels in relation to the detoxification mechanism were ob- served. The results showed that only rats in unsupplemented, 5 ppm Se-diet group exhibited distinct toxic manifestations, and supplementation of VE-Met to this group gave effective protection against the toxic action. In the supplemented group Se content of blood, liver, kidneys and skeletal muscle of the experimental animals was decreased, while the excretory rate of urinary trimethylselenonium ion was increased to a level of 33% in contrast to 22% in the unsupplemented group (P
ABSTRACT
Results obtained from previous studies shoved that at low level of dietary selenium(0.03 ppm) weanling rats fed with diets of low protein level usually possessed higher selenium concentration and GSHPx activity in their blood and tissues. The results were reproduced in chickens in this observation. Furthermore, even the original selenium level could not be maintained in blood and tissues of chickens fed with low protein diet (12.4%) because of faster growth rate and the lower selenium content (0.01 ppm) of the diet used in this study.Of the 27 chickens consuming 18.2% protein diet in the 14 days expe- riment, 23 suffered from exudative diathesis and 3 died without any sign of exudative diathesis, while in the 12.4% protein group only one of the 26 chickens suffered from exudative diathesis during the 14 days experiment and 6 of the 12 chickens in this group observed for another two weeks showed exudative diathesis. In the 18.2% protein group the first chicken with signs of exudative diathesis appeared on the 9th day while it appeared on the 14th day in the 12.4% protein group.How to improve the selenium nutritional status of the residents in Ke-shan Disease areas was discussed.
ABSTRACT
The content of selenium and several antagonistic metals such as mercury, arsenic, and cadmium in foods from Beijing market has been determined. Results showed that marine products, Viscera (particularly kidney), eggs, and mushroom were good dietary sources of selenium. The selenium contents of imported cereals and pulse are much higher than those grown in China as far as the sample analysed. Most vegetables and fruits contained selenium below a level of 0.010ppm with exception of garlic and mushroom.The selenium content of human milk was higher than other kinds of milk, milk products and milk-substitutes. Selenium content of Beijing foods was far higher than those in affected area of Keshan disease. The mercury, arsenic, and cadmium content of foods was below the National Allowance Standard except a few marine products.The selenium content of natural plant foods was positively correlated with its protein content (r=0.844, p
ABSTRACT
A convenient microbiological method with high accuracy for cystine assay was introduced. Common foods including cereals, beans, sweet potato, fishes and other aquatic products as well as meats were selected for cystine and methionine analysis. Based on the data obtained, a brief discussion was made on the way for resolution of sulfur amino acids problem inherently in our traditional soy-cereal based diet.
ABSTRACT
The average daily selenium intake of staff of the Institute of Health in Beijng was surveyed to be 66.4?g and that of children in nursery and kindergarten was 34.7?g, which could meet the Recommended Dietary Allowance as suggested. Cereals were the major source of dietary selenium which accounted for 63.6% of total dietary intake, and animal and plant foods provided about 25.9% and 10.5% respectively. Both cereals and animal foods were the major sources of selenium in children diet, which accounted for 48.9% and 44.3% respectively, and intake of selenium from other sources was negligible.The selenium concentrations in whole blood and hair of the population were 0.146ppm and 0.578ppm respectively, and both correlated well with the daily selenium intake.The daily intake of mercury, arsenic, and cadmium for population in Beijing were estimated to be 3.4, 52.7, and 42.7*g respectively, which were within the normal range of intake and would not significantly interfere with the bioavailability of selenium ingested. It was suggested thal these levels of selenium daily intake surveyed would be adequate for human consumption and could be helpful as a reference for the establishment of dietary allowance.
ABSTRACT
Total and water soluble selenium in soil, and total, tetravalent and he-xavalent selenium in drinking water were determined fluorimetrically by 2, 3-diaminonaphthalene. The digestive mixture was composed of sulphuric, perchloric acids and sodium molybdate 0.2 g of soil and 20 ml of water samples were sufficient for analysis when their selenium concentrations were at the level of 0.1 ppm and 1 ppb respectively. Coefficient of variation and recovery for soil was 12% and 92 ?6%, and for water was 4.3-5.8% and 98 ?2% respectively. Tetravalent and hexavalent selenium content could be measured differentially by the addition or omission of hydrochloric acid in ordinary water samples containing only small amounts of organic matter. In addition to tetravalent selenium substantial amounts of hexavalent selenium may occur occasionally in drinking water and it is thus necessary to add hydrochloric acid to the final digests to completely reduce hexavalent selenium to the tetravalent state for the estimation of total selenium in water samples.
ABSTRACT
Lysine and methionine contents were determined in proteins of 21 rice samples including 17 varieties grown in 11 provinces. Ranges of lysine and methionine contents on crude protein basis were 3.21-3.76% and 1.63-2.06% respectively. The lysine content was found to be negatively correlated with the protein content of rice, but no correlation was found in case of methionine when they were expressed on the basis of crude protein. The absolute amounts of lysine and methionine were positively correlated with protein contained in the samples. The importance of breeding rice variety with protein of high lysine content was discussed in relation to promoting the protein nutritive status in South China.
ABSTRACT
2,3-Diaminonaphthalene was used for the fluorometric determination of selenium in cereals and vegetables. Nitric-perchloric-sulphuric acids mixture was used for digestion. Coefficient of variation and recovery for cereals were 4-10% and 97.1%, and for vegetables were 4-18% and 97.8% respectively. Addition of hydrochloric acid to the final digests could be omitted for ordinary cereals and soybean, but it was necessary for samples from seleni-ferous area and some vegetables with higher selenium content such as mushrooms.
ABSTRACT
Whole rice grain was dissected by hand into fractions of pericarp, ale-urone, scutellum, embryo and endosperm. For the convenience of having enough amount of samples for amino acids assay some of which were recom-bined and finally three parts, pericarp +aleurone layer, scutellum + embryo and endosperm, were obtained. Protein, lysine, methionine, threonine and valine contents were determined for each part. The data obtained indicated that although total weight of the first two parts accounted for only 7.27-8.43% of the whole grain, they contributed 14.5-15.8% protein, 29.0-30.5% lysine, 11.8% melhionine, 16.8% valine and 19.4% threonine, contained in the whole grain. During husking process it indicated that the lesser amounts of pericarp, aleurone, scutellum and embryo were retained and the larger percentage of protein and lysine was lost. This fact was identified either by a specially designed miller in the laboratory or a commonly used sand wheel miller in the factory. The suitable degree of milling for rice was discussed and it was proposed that 92% extration for rice rather rational.
ABSTRACT
A modification of Watkinson's method was used for the flaorimetric determination of selenium in blood, hair, urine and animal tissues with 2,3-Di-aminonaphthalene. A mixture of sulphuric, perchloric acid and sodium molybdate was used for digestion. As little as 3 ng selenium in the sample could be estimated out. Coefficients of variation and recoveries for blood, hair, urine and animal tissues were 3.9, 5.5, 3.3 and 5.6%, and 97.0, 95.0, 97.8 and 99.8% respectively. No significant difference in selenium content estimated was found as graded amounts of samples were taken for analysis, indicating no foreign interference in the extracts. Both precision and accuracy of this method are satisfactory.
ABSTRACT
Blood GSHpx activities of populations living in Keshan disease affected and non-affected areas were examined. The enzyme activities of people in affected areas were lower than that in non-affected areas. That of agricultural population is lower than that of workers and staff members living in same affected areas. The enzyme activities of patient suffering from Keshan disease were a little lower than that of other children. After oral administration of Na2SeO3 for one year, the enzyme activities of children in affected areas increased to the same level of that in non-affected areas. Significant correlation was found between selenium concentration of blood and hair and GSHpx activities.
ABSTRACT
Four different methods are suggested for the practical supplementation of selenium to the residents in Keshan Disease areas. They are: distribution of selenite tablets, enrichment of table salt with sodium selenite, use of foliar sprays on grain crops and selection of relatively selenium-rich foods in affected areas.Selenium contents of corn and rice could be raised to a level of about 0.07 and 0.05 pprn respectively by application of foliar sprays. A vailability of the increased selenium is similar to that occurred naturally in corn, as demonstrated by animal experiment. Furthermore, by this method the bio-availability of selenium is better than the other methods of administration.Observation on residents who were treated with selenite table salt for three years and three months revealed that the salt enriched with 10 ppm of sodium selenite is enough to maintain the residents' hair selenium concentration to a level above 0.2 ppm, if an average of 15 g of the salt could be taken from meals daily by an adult. Either by calculation based upon 10 ppm of sodium selenite concentration suggested or by dietary survey, a daily selenium intake of around 60 ?g is required to maintain such a hair selenium level.Since about a half-year's administration is required in order to raise the hair selenium level above 0.2 ppm, an extraoral selenite tablet supplementation seems needed during the early stage of Se table salt treatment.Availability of selenium in selenite iodized table salt is not altered either after one-year storage or after manufacture for fermented soybean curd or salted vegetables. No harmful substance was detected during manufacture of dishes as evidenced by animal experiment.Fresh water products such as shrimps, eels, small fishes and loaches, as well as various species of mushrooms were found to be selenium-rich foods in Keshan Disease area. Their selenium contents ranged from 0.3 to 1.0 ppm.The authors are of the opinion that one may select any method introduced above and at the same time urge the people to take more selenium-rich foods in their diets, thus residents in Keshan Disease areas would obtain enough selenium to prevent them from being seleniumdeficient.