Dietary fiber has been suggested as interfering with mineral utilization. The influence of broccoli florets and wastes, cauliflower heads and wastes, wheat bran and Metamucil on mineral uptake by the rat was determined using balance studies. All results were compared to control animals fed diets containing 10% hydrolyzed cellulose. Utilization of Ca, Mg, Cu, Zn and Fe were determined to be 62, 33, 23, 42, and 52% respectively for control animals. The uptake of Mg, Zn and Fe were significantly reduced to 12, 16 and 18% respectively from broccoli florets. Broccoli wastes decreased absorption of Zn to 14% and created a negative iron balance. Cauliflower heads improved Zn assimilation to 61%. Cauliflower wastes depressed Ca absorption to 26% and caused Mg balance to be negative. Wheat bran improved utilization of Ca and Zn to 88 and 54% respectively. Metamucil increased uptake of Ca to 88% and Mg to 53%. Copper balance was unaffected by any test diet. To better understand results of balance trials, the bioavailability of Fe from some sources was measured. The relative biological values (RBV) of endogenous Fe in broccoli, cauliflower, Brussel sprouts and wheat bran were determined to be 93, 88, 83, 98% respectively. These values were obtained using rats fed control diets containing 5% hydrolyzed cellulose and ferrous sulfate (RBV = 100). The efficiency - true bioavailability of utilizing dietary Fe is approximately one-half of the RBV. These values agree well with apparent uptake of iron by animals in the balance trials for all diets except broccoli. This exception may be due to differences in the amount and source of broccoli fed. High dietary levels of broccoli florets and wastes appear to interfere with utilization of Fe and Zn. Cauliflower wastes depress absorption of Ca and Mg. With the exceptions noted, dietary fiber from plant sources does not appear to decrease the utilization of minerals by the rat. The nature of mineral complexes in plants may be more important in defining the degree of its absorption. / Graduation date: 1980

Thesis (M.S.)--University of Kentucky, 2006. / Title from document title page (viewed on August 22, 2006). Document formatted into pages; contains: x, 99 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 90-98).

Availability of six minerals (Ca, P, Mg, Mn, Zn, and Cu) in commercial wheat, triticale, corn and barley samples was estimated with three-week old growing chicks. Effects of soybean meal and wheat fed at different dietary concentration on availability of these minerals were studied. The availability of minerals from specific inorganic sources were also evaluated. Availability value was determined by a balance procedure corrected for endogenous minerals. Results indicated that the availability of calcium, phosphorus, magnesium, manganese, zinc, and copper was 71.0, 67.4, 53.5, 48.4, 49.6 and 78.5%, respectively for the wheat and triticale samples. Copper availability was the highest in corn (87.2%), followed by calcium (70.0%), phosphorus (60.9%), manganese (60.0%), zinc (57.5%) and magnesium (51.0%). The availability of Ca, P, Mg, Mn, Zn and Cu in barley was 68.9, 68.8, 54.9, 54.9, 49.1 and 77.5%, respectively. Significant variation (P ≤ 0.05) exists among the cereal grains tested. Results indicate that mineral availability is influenced by the origin of the samples obtained. Availability of minerals is affected by the concentration of ingredients in the test diet. Significant differences (P ≤ 0.05) were observed in availability for all the minerals tested when soybean meal and wheat were supplied in the test mixture at five levels. Calcium and phosphorus from calcium phosphate were highly available to growing chicks. However, the availability decreased rapidly when the mineral level was in excess of the dietary requirement. Six levels of magnesium (150, 300, 450, 600, 750, and 900 ppm) from magnesium carbonate were evaluated. Results showed that magnesium was highly available to growing chicks. The values ranged from 82.3 to 61.9%. Excess amounts of magnesium in the diet tended to reduce the availability value. Various levels (25, 50, 75, 100 and 125 ppm) of manganese from manganese sulfate were tested. Manganese appeared to be poorly available for the levels tested. Zinc availability from zinc oxide was highly available for the chick. The availability values/ranged from 84.4 to 93% for all the diets containing 25 to 125 ppm of zinc. The availability of copper from copper sulfate was moderate to high (72.1-80.2%) for the low dietary copper concentrations (2-32 ppm). However, the copper availability values (61.8-63.6%) tended to decrease at higher dietary concentration (50-250 ppm). / Land and Food Systems, Faculty of / Graduate

Thesis (M.Sc.) --University of Adelaide, 1958.

Thesis (DVSc (Production Animal Studies))--University of Pretoria, 2002. / Includes bibliographical references.

Call number: LD2668 .T4 1960 B74

Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Studies were conducted to determine the effects of feeding lasalocid and monensin upon mineral status of ruminants, changes in digestive and renal physiology which bring about altered mineral status, and the effects of dietary K upon the actions of ionophores. Two 84-d grazing trials were conducted with steers fed no ionophore, 200 mg lasalocid, or 150 mg monensin. Monensin tended to increase gain of steers, but lasalocid had no effect. Feeding supplemental lasalocid and monensin altered Ca, P, Mg, Na, K, Cu, Fe and Zn status of grazing steers, but effects were not consistent. Twenty-four crossbred steers were individually fed in a 147-d finishing trial to study a possible K x monensin interaction. Steers were fed diets ad libitum containing .4% or 2.3% K, with or without 23 ppm monensin, dry basis. Feeding monensin with low K increased serum Na, Mg, inorganic P, Cu and Zn, but monensin fed with high K had no effect or decreased these serum minerals. Fifteen wethers, fitted with abomasal and ileal cannulae, were fed a basal diet alone or supplemented with 23 ppm lasalocid or monensin; Apparent absorption of Mg, K and Fe increased when ionophores were fed. Magnesium flow through the small and large intestines was decreased by lasalocid and monensin. Effects of lasalocid and monensin differed for metabolism, digestive tract flow and (or) partial absorption of Ca, P, Cu, Fe and Zn. Twelve ewe lambs were used in a renal clearance experiment. Lambs were fed a basal diet with no ionophore, 23 ppm lasalocid, or 23 ppm monensin, dry basis. Ionophores were fed starting on d 1 of the experimental period. Serial collections of blood and urine were made during d 1 and d 5 of the experimental period. Monensin reduced urine flow rate at d 1 and d 5. Feeding monensin lowered serum clearance and urinary excretion rates of Na and K at d 5. Serum clearance and urinary excretion rates of Ca were lower in sheep fed ionophores at d 1. Feeding monensin decreased serum clearance and urinary excretion rates of Cu at d 1. At d 5, urinary excretion rates of Zn were greater when lasalocid was fed, and lower when monensin was fed, compared to feeding no ionophore. These studies indicate that dietary lasalocid and monensin can alter mineral status of ruminants, although their effects may differ. The effects of ionophores may be dependent upon dietary K levels. / Ph. D.

Call number: LD2668 .T4 1984 G37 / Master of Science

The factors affecting the accumulation of nitrate in kikuyu grass pastures and the effect of elevated nitrate levels upon digestion in the ruminant were investigated. A high potassium level in the soil seems to be the major factor stimulating the accumulation of excessive amounts of nitrate in kikuyu grass, when the nitrate content of the soil is also high. The continuous elongation of kikuyu grass tillers allows constant exposure of high nitrate containing stem tissue to the grazing ruminant. Digestibility studies in vitro showed that nitrite, formed during the assimilatory reduction of nitrate to ammonia, reduces cellulose digestion, but the degree of reduction also depends upon the presence of readily available carbohydrates and protein in the digest. Studies in vivo showed that the microbial population can adapt to metabolise high concentrations of nitrate (500 mg% N, m/m) in fresh kikuyu grass, without the accumulation of nitrite in the rumen. However, introduction into the rumen of nitrite in excess of the capacity of the nitrite reducing microbes, causes nitrite accumulation. Nitrite has no direct effect upon rumen cellulase activity. Due to the affinity of rumen carbohydrases for the substrate, attempts to isolate these enzymes by means of isoelectric focusing and other separation techniques met with limited success. Nitrite strongly reduces the xylanolytic, total and cellulolytic microbial numbers with a concomitant decrease in xylanase and cellulase activity of the digest. Decreased microbial numbers could not be .attributed to a less negative redox potential of the digest in the presence of nitrite, nor could the effect upon the cellulolytic microbes be attributed to an effect of nitrite on branched chain fatty acid synthesis required for cellulolytic microbial growth. A study of the effect of nitrite upon the specific growth rate of pure cultures of the major cellulolytic bacteria, Ruminococcus flavefaciens strain FDI, Butyrivibrio fibrisolvens strain Ce 51, Bacteroides succinogenes strain S 85 and Ruminococcus albus strain 22.08.6A and the non-cellulolytic bacterium Selenomonas ruminantium strain ATCC 19205 revealed the extreme sensitivity to nitrite of some of these bacteria and the relative insensitivity of others. Growth inhibition seems to depend primarily upon the extent to which these microbes derive their energy from electron transport-mediated processes. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1985.