Techn. Hochsch., Diss., 2005--Aachen.

Selenium (Se) is an essential mineral nutrient for animal and human growth. Defici-ency in this element is a worldwide nutrition problem. Lolium perenne and Trifolium pratense were enriched by selenium using foliar application. It is a way to enrich the feed of animals and human nutrition through animal products. Amounts of 0, 2, 4 and 20mg of Se m-2 were applied both as sodium selenate and as sodium selenite in water. Results showed that selenium concentration in forage was significantly enhanced dose dependently. For Lolium perenne at the highest concentration used, reaching concent-rations of selenium in selenate 3,1371mikrogramm/mg and selenite 5,5503mikrogramm/mg. For Trifolium pratense at the highest concentration used, reaching concentrations of selenium in sele-nate 11,6837mikrogramm/mg and selenite 4,939mikrogramm/mg. Foliar application of selenium was proven to be a good way to increase the selenium content of forage, but the assimilation process of selenium was simpler with selenate for Trifoilum pratense and with selenite for Lolium perenne.

The aim of this thesis was to create a research of scientific literature and then experimentally determine the influence of selenium, vitamin C and E on biochemical indicators of boars ejaculate (antioxidant capacity, selenium concentrations, enzyme activity). Ten boars of the Duroc breed were used and they were divided into 2 groups. All animals were feeding 3.3 kg basic feed mixture that contained 0.02 mg of selenium, 9.9 mg of vitamin E and 16 mg of vitamin C per kilogram of compound feed. The experimental group of boars was added of 0.5 mg selenium (selenomethionine); 70 mg of vitamin E (alpha-tocopherol) and 350 mg of vitamin C (ascorbic acid) per kilogram of diet. Biochemical parameters were positively influenced by an addition of organic selenium, vitamin C and E. Antioxidant capacity of the organism, the level of GSH-Px and superoxide dismutase increased. Level of metalothionenin and selenium were relatively unchanged. The results of the methods used in our experiment showed, that supplementation of feed affects antioxidant mechanisms of the animals.

The aim of this thesis was to evaluate the effect of increased intake of selenium from the diet of rats with spontaneous hypertension (SHR) on other essential elements. The effect of different diets on the element levels in kidney, liver, testes, and blood of rats was observed under model conditions. Tested rats were divided into five groups, where the first group A was the reference group and feed mixture contained no additive. In groups B and C was soybean meal replaced by defatted rapeseed and into feed mixture of group C was additionally added vitamin E. Diet groups D and E contained added selenium and zinc, and group E contained additionally vitamin E in comparison to reference group A. Se content in kidney, liver, testicles, and blood of animals was determined by inductively coupled plasma mass spectrometry (ICP MS). The other essential elements (Cu, Fe, Mn, P, S, and Zn) were determined by inductively coupled plasma optical emission spectrometry (ICP OES). The content of Ca, K and Mg was determined by atomic absorption spectrometry with flame atomizer (F-AAS). The hypothesis has been that the increased intake of selenium should improve the use of other essential elements by the rat organism. It was expected that there will be influenced elements mainly involved in the defense of the organism against oxidative stress. This was not confirmed by this experiment. Changes in the concentrations of these elements occurred only at very high dose of selenium that is already toxic to the organism. This toxic effect could be also responsible for fifty percent mortality of rats in group E, where perhaps even increased concentration of vitamin E could not sufficiently reduce the toxicity of high doses of selenium.

The aim of this thesis was to develop a literature search and experimentally determine the effect of organic forms of selenium levels (0.3 and 0.6 mg/kg FM) of selenium on the antioxidant status in postpartum sows. Experiment included 18 sows in the postpartum period, which were divided into three groups according to age. The model animals were divided into three groups. The first group (Se1) sows (n = 6) served as a control, wherein the addition of selenium has not been increased. The second group (Se2) sows (n = 6) were fed 0.3 mg Se/kg FM. Third group (Se3) sows (n = 6) were fed 0.6 mg Se/kg FM. Premix was dosed in the morning feeding. To supplement selenium were used selenium enriched yeast (Sel-Plex - Alltech's). The results show that the dose of selenium in an amount of 0.30 and 0.60 mg/kg FM, increase the activity of antioxidant enzymes, glutathione peroxidase and superoxide dismutase. Glutathione peroxidase (GPx) after supplementation with 0.3 mg/kg selenium increased from the second sampling, but the third sampling was statistically significant (P <0.05). Doses of 0.6 mg/kg selenium also visibly increased level of glutathione, but these results can not be statistically demonstrated. Superoxide dismutase (SOD) at both doses (0.3 and 0.6 mg/kg) appeared selenium statistically not detectable visible growth. We also found an increase of antioxidant activity measured by the methods ABTS, FRAP and FR, although the methods ABTS and FR showed slight fluctuations. The amount of reduced and oxidized glutathione were also significantly (P <0.05) higher in both experimental groups. The selenium content of selenium supplementation significantly affected when the results of both experimental groups were statistically significant (P <0.05) higher. Level malonyldialdehydu (MDA) after supplementation with 0.3 mg/kg selenium statistically proven (P <0.05) increased in the third collection at 0.6 mg/kg selenium, we observed statistically demonstrable (P <0.05) increase from the second collection. We can therefore conclude that selenium supplementation in organic form, can reduce oxidative stress in confinement of sows and overcome this stressful period for the organism.

No description available.

Šnajdr Vladimir: Selenium in the diet of dairy cows in organic farming, Final thesis, Mendelu Brno, 50 pages. Selenium is one of a number of trace elements that are indispensable for the life of all species. Exceeding limits of the daily dose of selenium in the diet can cause toxicity of tthe organism. However, selenium deficiency can lead to diseases, particularly for species with high susceptibility to various kinds of diseases. The aim of the thesis was to investigate the influence of dietary selenium on qualitative and quantitative parameters of dairy cows in organic farming. The experiment itself was made on an organic dairy farm. The experiment involved 20 pieces of Holstein breed cows. They were divided into two balanced groups being at same stage of lactation. All the cows were fed a basic ration in the form of TMR with the addition of mineral premix Detamin GA Spezial designed for organic farms. The experimental and control group of cows took of 20.5 kg dry matter of feed/head/day. The basal diet contained 0.17 mg selenium /kg. Animals had ad libitum access to water. Selenium was added to the diet at the dose of 0.3 mg/kg (as selenomethionine) in the first group of cows (n=10). The second group of cows (n=10) served as a control without addition of selenium (control group of animals received only selenium from native sources). At the end of the experiment was after administration of selenium in the diet after 15 days in the group of cows examined detectable amount of selenium, which was constant throughout the duration of the experiment. The experimental group with selenium level ranged from 15 to 45 days in the interval from 0.13 to 0.15 mg/ml. In the control group, the amount of selenium throughout the entire duration of the experiment under the detection limit. The quantity of somatic cells was significantly reduced in the test group cows 128 thous./ml (P <0.05). Reducing the number of somatic cells was also observed even in the control group (about 49 tis./ml). The urea concentration significantly decreased in the experimental and control groups of 14.3 mg/100 ml (P <0.05) respectively about 13.7 mg/100 ml (P<0.05). The addition of selenium can improve animal health and to ensure the production of so-called functional foods Formula clause:Prohlašuji, že jsem práci: Selen ve výživě dojnic v ekologickém chovu vypracoval samostatně a veškeré použité prameny a informace uvádím v seznamu použité literatury. Souhlasím, aby moje práce byla zveřejněna v souladu s § 47b zákona č. 111/1998 Sb., o vysokých školách ve znění pozdějších předpisů a v souladu s platnou Směrnicí o zveřejňování vysokoškolských závěrečných prací. Jsem si vědom, že se na moji práci vztahuje zákon č. 121/2000 Sb., autorský zákon, a že Mendelova univerzita v Brně má právo na uzavření licenční smlouvy a užití této práce jako školního díla podle § 60 odst. 1 autorského zákona. Dále se zavazuji, že před sepsáním licenční smlouvy o využití díla jinou osobou (subjektem) si vyžádám písemné stanovisko univerzity, že předmětná licenční smlouva není v rozporu s oprávněnými zájmy univerzity, a zavazuji se uhradit případný příspěvek na úhradu nákladů spojených se vznikem díla, a to až do jejich skutečné výše.

Im Rahmen dieser Diplomarbeit wurden Si(001)-Oberflächen mit Selen modifiziert und anschließend charakterisiert. Die Herstellung der Selenpassivierungsschichten wurde in einer MBE-Anlage durchgeführt. Die Charakterisierung erfolgte durch RHEED-, LEED- und RBS-Untersuchungen.

Hohenheim, Univ., Diss., 2008.

Heidelberg, Univ., Diss., 2008. / Online publiziert: 2008.