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The effects of three dietary selenium (Se) levels (0.15, 0.35 and 0.5 mg/kg dry matter (dm) and of two Se-compounds (sodium selenite and Se-yeast) on the Se-status, liver function and claw health were studied using 36 fattening bulls in a two-factorial feeding trial that lasted 16 weeks. The claw health was assessed macroscopically and microscopically. Compared to the two control diets containing 0.15 mg Se/kg dm, the intake of the diets containing 0.35 and 0.50 mg Se/kg dm significantly (P < 0.05) increased the Se-concentration in serum, hair, liver and skeletal muscle. Compared to sodium selenite the intake of Se-yeast resulted in significantly (P < 0.05) higher Se-concentration in serum, liver and hair. Concerning the claw horn quality, there was no significant difference between the different groups; the animals receiving organic Se tended to have a better histological score (P = 0.06) at the coronary band than the groups fed with sodium selenite. The serum vitamin E level decreased significantly (P < 0.05) with increasing Se-intake, which had no influence (P > 0.1) on growth and liver function parameters. With the exception of the decrease of the serum vitamin E level indicating an oxidative stress caused by a high Se-intake, no negative effects of dietary selenium exceeding recommended levels for 4 months were observed.

A review is given on the significance, availability, metabolism and application of vitamin E and selenium in sheep. Vitamin E deficiency commonly occurs in spring. Selenium deficiency occurs in certain areas where the selenium content of plants is low. A further factor is the low availability of selenium as a consequence of reduction reactions in the forestomachs. When the supply of vitamin E and selenium is suboptimal, activity of the immune system and growth are impaired.

Unlabelled: Development and growth of gastrointestinal tumors seems to correlate closely with the formation of reactive oxygen intermediates (ROI). It is known, that oxygen-free-radicals are able to induce a precancerous stage and tumor growth by damaging DNA or changing the protein and lipid structure. To investigate, whether the cellular formation of oxygen-free radicals plays a role in the pathogenesis of colorectal carcinoma, we performed the study presented here. 40 patients with colorectal carcinoma were studied over a period of 6 months (before operation, 10 days after operation, 3 months later, 6 months later). Oxygen-free radicals were determined by chemiluminescence response in the whole blood, in granulocytes and in monocuclear blood cells (MBC). At the same time the trace elements selenium, Copper and Zinc, known to play an important role as antioxidants, were measured., Results: We observed, that the ability of granulocytes for phagocytosis was depleted. However, this effect could be reversed as demonstrated in in vitro stimulation assays. After 6 months the phagocytosis by granulocytes achieved again normal values. Simultaneously a dramatic increase in superoxide-anions generated by mononuclear blood cells was seen. This increase was still obvious after 6 month. Independent of the tumor state selenium deficiency was found in all patients. Since no substitution of selenium was performed after operation, this deficiency was not normalised., Conclusion: The ability for phagocytosis and therefore the immune response is reduced in a reversible manner. In addition reactive superoxide-anions, that are able to induce tumors, are formed. This risk is increased in the absence of selenium. Thus, clinical follow-up studies are needed to determine subclinical tumor relapses and to investigate the role of oxidative stress by chemi-luminescence. As consequence of this study selenium substitution seems to be indicated.

In a 2 x 3 factorial arrangement with 30 male castrates (German Landrace; 13.7 +/- 1.7 kg b.w.), after a 2 week feeding period with a maize/torula yeast basal diet poor in selenium and without vitamin E supplementation, the effect of two ethoxiquin concentrations (0 and 150 mg/kg) und 3 selenium concentrations (0.075, 0.10 and 0.125 mg/kg) on growth, the activity of the Se dependent GSH-Px in the erythrocytes and the Se concentrations in liver, kidney, heart and diaphragm was measured after 4 weeks on the experimental diets. Under the experimental conditions chosen ethoxiquin had no effect of any of the parameters studied. Selenium supplementation significantly increased the enzyme activity and the Se concentrations in the organs and tissues analyzed.

In two metabolism trials with growing and finishing pigs the effect of the antibiotic feed additives Avilamycin and Tylosin on the apparent digestibility of Fe, Zn, Cu, Mn and Se was investigated. The feed additives were supplied to the diet in levels of 40 ppm (growing pigs) and 20 ppm (finishing pigs) each. Dietary contents of Fe, Zn, Cu, Mn and Se covered the requirements of all treatment groups. Avilamycin and Tylosin increased the apparent digestibility by 4 (Fe), 4 (Zn), 5 (Cu), 2 (Mn) and 2 (Se) percentage units on an average.

The importance of selenium as an essential trace element has progressively emerged during the last years due to the analysis of selenium deficiency diseases and to the identification and characterization of a number of selenoenzymes. Selenium is incorporated in the catalytic site of the enzymes as an integral selenocysteine residue. The pathway of selenocysteine biosynthesis and incorporation has been elucidated recently for Escherichia coli. This article presents an overview on these subjects and describes the mechanisms which confer selenocysteine specificity in the framework of protein biosynthesis. In addition, some considerations concerning the phylogeny of selenocysteine incorporation are presented and a model for the evolution of the selenocysteine pathway is proposed.

In two trials with sows of German Landrace at different dietary selenium levels glutathione peroxidase activity (GSH-Px activity) in plasma was determined at day 60, 90 and 110 of gestation, day 5, 15 and 25 of lactation and day 7 post weaning. In three groups of five first-litter gilts receiving 0.1, 0.3 and 0.5 mg selenium per kg diet, GSH-Px activities dropped within the treatments, independent of dietary selenium, from day 60 of gestation to a minimum at day 5 and 15, respectively, of lactation and increased again after weaning. Highest enzyme activities were observed at the 0.5 level. In another trial, 127 reproductive cycles of sows in first, second and third parity, respectively, with 0.1, 0.5 and 0.9 mg dietary selenium were investigated. GSH-Px activity showed results comparable to those of the former trial. Selenium content of plasma increased linearly as dietary selenium increased. In all cases, results of GSH-Px activity and of plasma selenium were confirmed by regression analysis. Reproductive performance ameliorated with increasing dietary selenium. Especially piglet's gain from birth to weaning and litter weight at weaning increased significantly. Furthermore, percentage of still born piglets showed a minimum at the selenium supplementation of 0.5 mg/kg diet. The pattern of GSH-Px activity in plasma and the improved reproductive performance of animals imply that the requirement of the sow during the reproductive cycle is met a level of 0.5 mg selenium per kilogram diet.

In experiments on 72 rabbits, the LD50 of sodium selenite by intravenous injection was found to be 2.24 mg/kg body weight. The clinical picture and pathological changes associated with acute selenium poisoning are described. The increase in selenium concentration was up to nine times the normal in liver and up to six times in kidney and muscle. There was no sign of a return to normal values 24 hours after administration.

An explanation of the functions of both vitamin E and selenium in metabolism and an account of the correlations between them is followed by reference to the results obtained by the authors of this paper from studies into the effects of dl-alpha-tocopherol on selenium levels in the M. longissimus dorsi, blood, and liver as well as on the activity of glutathione-peroxidase (EC 1.11.1.9) in erythrocytes of rabbit and rat, following application of therapeutic doses of selenium (0.5 mg/kg live weight). In both species selenium application increased the glutathione-peroxidase activity in erythrocytes. Vitamin E had no additional effect. Application of selenium was followed by rise in intraorganic selenium concentrations. In rabbit, the effect of vitamin T on intraorganic distribution of selenium caused an increased of the selenium level in the liver, but not in the muscles. No vitamin E effect was recordable in the rat. The findings are discussed, with conclusions being suggested for the treatment of metabolic disorders in the context of selenium and vitamin E and for non-invasive liver therapy.

There is a potential risk of excessive selenium levels in organs of swine, resulting in toxicity and residues in pork, or selenium deficit. Therefore, random selenium mean values in "selenium-indicating" organs of pigs selected from suspicious populations were compared with mean and limiting values (reference or normal values) recorded from animals with intact metabolism. Prerequisites required for such comparative assessment included the availability of estimated variance values and knowledge of the presence of abscence of agreement between normal distribution and empirical frequency distribution for the population concerned. Knowledge must be available also on the informative value of measured selenium data in blood plasma and their relevance to the general selenium situation in the organism and muscle at large. These were some of the problems studied by determining selenium levels in the liver, kidneys, blood plasma, and M. longissimus dorsi. Organic selenium concentrations were found to be distributed with right axis deviation but almost normal. The parameters established were typical of the majority of data known from literature. Those date, however, are quite variable, so that the need for independently prepared reference values cannot be abandoned. Correlation analysis showed reciprocal relationships between selenium levels in blooc plasma, liver, and muscles but much less correlation between these, on the one hand, and selenium in kidneys, on the other. The correlations between blood plasma and muscle selenium were close enough to take blood plasma values recorded from the living animal as reference from which to draw conclusions as to the muscular selenium state.

In a feeding trial, rabbits allotted in 3 experimental groups were fed rations containing 2.09, 9.83 and 19.5 mg selenium/kg feed in the form of selenium-enriched alfalfa green meal pellets. The selenium enrichment was done by foliar application (spraying) of the 20--25 cm high plant stand with 2.5 kg SeO2 per hectare in watery solution. The control animals were given normal alfalfa green meal pellets of 0.16 ppm selenium content. Toxicity and lethality, tolerance limit and nutritive effect of the pellets were studied. Plant-assimilated selenium was found to be converted more efficiently by the animal organism than was selenium from inorganic compounds (higher retention rate, better gain in body weight and lower feed expenditure). Therefore, the selenium supply to farm animals should be improved by feeding crops that were given selenium dressings.

Recent knowledge concerning the importance of vitamin E and selenium for the health and functional capacity are demonstrated. A lack of vitamin E in man was up to now proved only in immaturely born children, in whom the application of a water-soluble vitamin E preparation is to be recommended. In adults in endangiitis obliterans a favourable influence by higher dosage of vitamin E was established. The need of vitamin E depends on the supply with selenium, with unsaturated fatty acids and with S-containing aminoacids. Selenium is necessary for the synthesis of glutathion peroxidase. The vitamin E is mainly effective in the degradation of fatty acid-peroxide compounds in the membranes, the glutathion peroxidase in the soluble proportions of the cells. By numerous works of animals experiments importance of the two essential nutrition factors for the preservation of structure and function in the molecular region was clarified. The vitamin E is, among others, important for the detoxication processes in the liver and for the immune defense.

A collective of 60 rats was divided into 3 groups of 20 non-pregnant, 20 pregnant without interference of the pregnancies and 20 pregant with ligature of the uterine vessels to induce an intrauterine growth retardation. The organ distribution of 100 muC intravenously injected 75-Se-methionine, which is actively transported from the placenta into the fetal circulation, was computer-scintigraphically measured. After 30 minutes and 6 hours typical differences, amongst the 3 groups, between the liver and foetoplacental unit methionine uptake were demonstrated both visually and quantitatively. On the basis of this experimental animal model, it should be attempted to measure quantitatively the placental disorders which are not caused primarily by perfusion of the uteroplacental unit.

LD50/24hr was established in the first of a series of experiments on 72 rabbits for orally applied sodium selenite. The dosage was 8.62 mg/kg live weight, the confidence interval being (1 - alpha = 0.95) +/- 0.13 mg/kg. The value was four times as high following intravenous application. Complete lethality was recorded from 15 mg Na2SeO3/kg live weight within 21 hours. Thirty-six animals were involved in the second experiment of the series. They had 50 or 100 per cent Ursoselevit-Prämix (30 ppm Se) in their rations. Body mass development of the test animals was superior to that recorded from the controls in the first 50 days, after which limit the former declined strongly in a few days. Their general condition worsened. Postmortem findings, following slaughter, included catarrhal enteritis, toxic liver dystrophy, scattered pulpous tumours in the spleen, and interstitial nephritis. In the third experiment (50 per cent Ursoselevit-Prämix with 60 ppm Se in the rations), the test animals developed better than the controls during the first two months, after which point they exhibited the same clinical symptoms as those observed in the second experiment, stopped to put on weight, and eventually turned cachectic. The pathomorphological findings were identical with those obtained from the second experiment. The selenium concentrations in the organs of the test animals all were much higher than those of the controls. Their amounts in excess to base values were up to eleven times in the blood, nine times in the liver, twelve times in the kidneys, and 13 times in the muscles.

White New Zealander rabbits were tested for erythrocyte-borne reference values of glutathion peroxidase Px activity, with correlations being established between that activity and selenium content of the blood. The average glutathion peroxidase Px activity in untreated clinically intact rabbits was 11.8 K/g Hb. That value doubled following five selenium applications in therapeutic dosage. The values empirically determined were well adapted to normal distribution. Selenium concentrations recorded from organs of control animals were in fair agreement with values established in earlier studies (Wiesner et al., 1978). The correlation coefficient was r = 0.7117 (n = 44, alpha less than 0.001). The equation of regressive straight line Y oder X (ŷ) was ŷ = -5.3 + 59.94x, and that of X over Y (ŷ) was ŷ = 0,27 + 0,0095y, when Y defined the activity of glutathion peroxidase Px and X the selenium level in the blood.

A Review and a report of our ten years experience with pancreas scans. The diagnostic value of 75Selen-Methionine (75Se) scan is limited because of the lack of organ specificity of this substance. There is no improvement by pharmacological stimulation of the pancreas or subtraction techniques of the 75Se-activity in the liver. In the early phase after the injection of 75Se the distribution is more favourable for the pancreas compared to liver and intestine. Four descriptive terms are in use: normal, spotted, organ defect, and lack of uptake. There are no specific signs for pancreatitis, carcinoma, or exocrine dysfunction. Considering these limiting factors the use of pancreas scans is valuable to exclude pancreatic diseases.

A feed loading experiment was applied in 2 phases to 45 young cocks over 12 weeks, using 1.2 (N, N-bis/methylmercury/-p-toluolsulphamide)-dressed wheat (50% of base ration). The experimental animals were White-Leghorn laying hybrids. Investigations were conducted to study the effects of exclusive exposure to mercury and those of mercury with addition of 0.2 mg of sodium selenite/l drinking water on biochemical parameters (calcium, phosphorus, total protein, albumin, creatinine, urea, activity of alkaline phosphatase, hematocrit, hemoglobin, and leucocyte count) as well as on parameters relating to toxicological residues (selenium and mercury levels in liver, musculature, and kidneys). Statistically secured differences were found to exist between the experimental groups with regard to selenium and mercury in the liver and mercury concentrations in kidneys. These data have shown that the problem of residualisation cannot be solved by selenium supplementation in parallel to methylmercury loading. The results recorded are likely to confirm the need for a general ban on feeding mercury-dressed seed.