Browsing by Subject "Selenium in animal nutrition"
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Item Absorption and tissue deposition of 51 chromium and 75 selenium from brewer's yeast in the mouse(Texas Tech University, 1982-05) Holland, Paula NellNOT AVAILABLEItem Diet modified aflatoxicosis(Texas Tech University, 1978-05) Haesemeyer, James FrederickNot availableItem Effect of dietary selenium and fat on the incidence of spontaneous mammary tumorigenesis of Cb3sH/StHa mice(Texas Tech University, 1985-12) Stoltenberg, PeggyThe purpose of this present study was to combine two dietary variables (Se 0, 0.1, 1.0 ppm and polyunsaturated fat as safflower oil or saturated fat as coconut oil) and observed the incidence and development of spontaneous mammary tumors in C-.H/StHa mice.Item Effect of dietary supplementation of selenium on the immune response in mature male mice(Texas Tech University, 1980-08) Shackelford, JodyNot availableItem Effects of Sel-Plex (organic selenium) and vitamin E on performance, immune response, and beef cut shelf life of feedlot steers(Texas Tech University, 2002-08) Clyburn, Bradley ScottSeveral experiments were designed to evaluate the differences of vitamin E level and selenium source on animal performance, selenium plasma concentrations, carcass characteristics, beef retail display, sensory characteristics, colostrum and milk components, and immunity in ruminants. Steers receiving Se yeast responded with an improvement in performance during the first 56 d, however, neither Se source nor vitamin E level affected performance over the entire 103 d experiment. Carcass quality measurements were similar among all treatments, however cattle supplemented with inorganic selenium and a moderate level of vitamin E responded with an increased loin-eye area. Lean muscle lightness of steaks aged 7, 14, and 35 d was improved with 50% less vitamin E when Se yeast was added to the diet. Steaks from steers fed no supplemental dietary Se or vitamin E, for all aging treatments, showed no difference in lean muscle lightness difference from the organic Se treatments with 125 lU and 500 lU of vitamin E nor the inorganic Se treatments at 35 d of aging. Neither selenium source nor vitamin E level influenced Warner Bratzler shear values. Selenium enriched yeast resulted in a greater Se colostrum concentration compared to inorganic Se and the control treatments, however, no differences were observed in milk Se concentration among treatments. Selenium yeast resulted in a greater colostrum Se concentration compared to inorganic Se and the control treatments, however, no differences were observed in milk Se concentration among treatments. Selenium source did not affect milk fat percentage between treatments. However, ewes supplemented with dietary inorganic Se showed a reduced colostrum (0 h) protein percentage compared to the control and the Se yeast treatments. Selenium source did not significantly affect milk lactose percentage among treatments. Additionally, non-fat solids percentage was reduced for all treatments after 6 h of lactation. Selenium source or supplementation had no affect on somatic cell count between treatments. Neither Se source nor supplementation affected ewe or lamb plasma Se or immunogloblin levels.Item Identification of methionine as a possible precursor to the selenocysteine catalytic site of glutathione peroxidase(Texas Tech University, 1985-12) Chung, Cha KwonNot availableItem In vitro hemolytic studies of selenium compounds and glutathione peroxidase and the effect of dietary selenium on resistance of mice to Klebsiella pneumoniae(Texas Tech University, 1983-05) Hu, Miao-linNot availableItem Influence of Ascophyllum nodosum on selenium and antioxidants in beef cattle(Texas Tech University, 2001-12) Cradduck, Will C.Tasco, a proprietary product derived from a brown kelp {Ascophyllum nodosum). has altered antioxidants in plants and animals. Selenium (Se) is a component of glutathione peroxidase, a cellular antioxidant, which is closely related to vitamin E in activity. Antioxidants have been implicated in the improved immune fiinction of steers and shelf life of the meat from steers that grazed pastures treated with Tasco. Therefore, experiments were conducted to determine the effects of Tasco products on Se concentrations in forage and cattle. In Experiment 1. Tasco-Forage (a water-soluble extract) was applied (3.5 kg/ha in April and July) to endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) -infected and endophyte-free tall fescue {Festuca arundinacea) grazed by Angus steers in Virginia during 1995 (initial mean BW 245 kg; SD = 20), 1996 (initial mean BW 234 kg; SD = 9), and 1997 (initial mean BW 265 kg; SD = 5). Tasco tended (P = 0.11) to decrease Se in endophyte-infected tall fescue and increased (P < 0.05) Se in endophyte-free tall fescue (interaction; P < 0.05) when averaged over years and dates. By the end of the grazing season, steers that grazed Tasco-treated fescue had higher (P < 0.05) Se in serum (1996) and whole-blood (1997) than steers that grazed non-treated fescue, regardless of the endophyte. Endophyte-infected tall fescue decreased (P < 0.05) serum Se (1996) and whole-blood Se (1997) compared with non-infected fescue. At the end of grazing, steers were finished on a feedlot in Texas. No differences in serum Se were observed following feedlot fmishing. In Experiment 2, Tasco-14 (a meal from dried, ground, intact A. nodosum) was fed (0, 1.5, or 3.0% of diet, DMB) to crossbred steers (Trial 1 initial mean BW = 332 kg, SD = 37; Trial 2 initial mean BW = 340 kg, SD = 18) during a 127-d eedlot finishing period. Steers were fed a diet based on steam-flaked com {Zea mays L.: Trial 1) or steam-flaked milo {Sorghum bicolor; Trial 2). No differences in serum Se were observed by harvest, but liver Se decreased linearly (P < 0.05) at harvest as a result of Tasco treatment in Trial 2. In Experiment 3, Tasco-EX fed to steers for the final 2-wk in the feedlot, at 0, 1, and 2% of the dietary DM had no effect on serum Se but linearly (P < 0.05) decreased serum vitamin A. Serum vitamin E of steers fed 1% Tasco did not increase as much as controls (P < 0.05) over the 2-wk period. Vitamin A, E, and Se were not affected in liver. In Experiment 4, sale bam heifers were supplemented (90 g d"' target consumption) with Tasco-EX in the drinking water for a 2-wk period. No effect on serum Se was observed at the end of the 2-wk supplementation period as a resuh of Tasco treatment. In Experiment 5, Tasco-14 was fed (0.18 kg hd'' d'') to Angus-crossbred (initial mean BW = 238 kg, SD=18) steers for 2-wk before transport to the feedlot, and for 2-wk after arrival. No effect of Tasco treatment on semm Se was observed immediately before or immediately after transport. No effect on whole-blood Se was observed 2-wk after transport. Tasco increased blood Se in grazing steers, but changes in blood Se only partially reflected differences in forage Se. Effects of Tasco on forage Se concentration depended on the presence of the endophyte. Application of Tasco to forage in Se deficient regions might improve Se status of grazing livestock. Presence of the endophyte decreased Se in the animal but not in the forage. Direct feeding of Tasco to steers did not aher serum Se, but decreased liver Se with long-term feeding and depressed serum vitamin A and E with short-term feeding. Treatment of beef heifers with Tasco in the drinking water did not aher serum Se. Tasco increased Se concentrations in endophyte-free tall fescue forage from Se deficient areas, but not endophyte-infected tall fescue. Other mechanisms working through the forage that are not totally understood, as well as ahered Se concentration of the forage, might provide an altemative to direct Se supplementation in deficient areas by increasing the Se status of cattle grazing both endophyte-infected and endophyte-free tall fescue.Item The amelioration of arsenic toxicity in Fischer 344 rats supplemented with selenite in the diet(Texas Tech University, 2002-08) Henderson, Lora SuzannePrior to the early 1970s, the people in rural areas of Bangladesh and West Bengal, India, where sanitary drinking water is scarce, had no ahemative to drinking severely polluted surface water (Henry 1990). During the 1970s, United Nations Intemational Children's Fund (UNICEF) fimded the digging of tube wells, which were to supply clean drinking water to the people from underground sources (Guha Mazumder 1998). In 1993, 10-20 years after the first wells were dug, people began developing unusual symptoms: hyperpigmentation of the skin on unexposed areas of the body, thickening of the pahns of the hands and soles of the feet, skin lesions (both malignant and benign), and ahered hver, nerve, gastrointestinal, and/or lung fiinction (Guha Mazumder 1998). These symptoms are all characteristic of chronic arsenic (As) toxicity. Testing water samples from the tube wells determined the water contained levels of As from less than 3 ppb, which is virtuaUy arsenic free, to over 1000 ppm (Chowdhury 2000), well above the tolerable hmits set by World Heahh Organization (WHO) (50 ppb) (Smith 2000). It has been estimated that 120 milhon people in Bangladesh and West Bengal have been exposed to unsafe levels (greater than or equal to 50 ppb) of As as a result of obtaining it in the drinking water from these wells (Chowdhury 2000). Attempting to alleviate the situation, WHO has ftinded many research projects (Anstiss 2001), mcluding those designed to remove As from the water, cheaply and effectively, as well as projects aimed at counteracting As toxicity in vivo. In the past, research has shown that As may amehorate selenium (Se) toxicity (Levander 1966b); As may act synergistically with Se (Obermeyer 1971); or Se may counteract As toxicity (Babich 1989). The objective of this study was to determine if Se counteracts As toxicity in rats. The first phase of research was designed to detennine two effects: the tolerable upper limit (TUL) of As as 50% arsenite/ 50% arsenate in Fischer 344 rats and the effects of dietary Se supplementation on As toxicity. Fourteen groups of 6 rats were given 0, 25, 50, 100, 150, 175, or 200 ppm As in the water and 0.2 or lOppm Se in the food. After evaluating the data from the first phase, a second phase was conducted to determine a level of Se suitable for amehorating As toxicity in rats at the TUL (50 ppm). Nine groups of 6 rats were given 0 or 50 ppm As in the drinking water and either 0, 0.2, 1.25, 2.5, or 5ppm Se in their food. The Se deficient diet (0 ppm Se) was introduced to mimic a potential Se deficient diet in Bangladesh or West Bengal (J. SpaUholz, personal communication, March 27, 2002). This study provides insight into the effects of Se supplementation on As toxicity, as well as demonstrates the TUL of As in rats. Once analyzed and summarized, the results of this study will be beneficial to those conducting ftirther research in As toxicity.Item The effects of dietary selenium, silver and methionine on glutathione peroxidase activity and cataracts in mice(Texas Tech University, 1985-05) Brigham, Dale EdwardNot available