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PubMedDate not supplied

Copper availability in seven Israeli soils incubated with and without biosolids.

Land application is becoming a preferred option for disposal of sewage sludge (biosolids) from wastewater treatment plants. However, it creates potential risks due to the heavy metal contents of these materials, with copper (Cu) being of chief concern. The long-term fate of biosolid metals applied to agricultural soils is not well understood, particularly in the soils of the Middle East. This investigation was conducted to determine whether the availability of Cu changes with time in biosolid-amended and nonamended soils from Israel. Seven soils, typifying the span of properties and formation environments encountered in Israel, were incubated with and without biosolids for 7 yr, and changes in organic carbon (OC) content and labile Cu concentration were determined. Isotopic exchange techniques, using 64Cu, and ion activity measurements, using a Cu2+ ion selective electrode, revealed that the available Cu concentration remained relatively low and stable over the 7-yr incubation. This was despite substantial reductions in OC. This study shows that, with regard to Cu, application of such biosolids to these soils at rates of up to 250 Mg ha(-1) does not pose a threat to the environment in the short to medium term.

Agriculture↗

PubMed2003

Modulation of the positive inotropic effect of pyruvate by energetic substrate availability.

Dependence of pyruvate's positive inotropic effect on energetic substrate availability and potential role of its mitochondrial uptake were investigated. Pyruvate (3, 10 and 15 mM) was added to rabbit right ventricular papillary muscles (protocol I; n = 10) and human right auricular trabeculae (protocol II; n = 6), using glucose as energetic substrate. In protocols III & IV (rabbit papillary muscles; n = 8 and n = 10, respectively) pyruvate's mitochondrial uptake was inhibited by alpha-cyano-4-hydroxycinnamate (0.5 mM) with octanoate as energetic substrate at 5 and 0.2 mM, respectively. In 8 additional rabbit papillary muscles, effects of L-alanine (10, 20 and 50 mM) were tested. In protocols I&II, pyruvate had a dose-dependent positive inotropic effect that was maximal at 10 mM, increasing in rabbit myocardium: 45.0+/-9.4% active tension, 20.5+/-7.4% peak rate of tension rise, 32.5+/-8.6% peak isotonic shortening, 31.2+/-11.7% peak rate of lengthening, 27.8+/-3.2% twitch duration. In protocol III (5 mM octanoate), pyruvate's positive inotropic effect was still present and even enhanced, while in protocol IV (0.2 mM octanoate) it was decreased and not observed with 3 mM of pyruvate. We conclude that, in rabbit papillary muscles, the positive inotropic effect of pyruvate is modulated by the availability of metabolic substrates and presumably does not depend on its mitochondrial uptake.

Alanine↗

PubMed1979

Biological availability of zinc from inorganic sources with excess dietary calcium.

The effects of chemical form of supplemental zinc and elevated dietary calcium on intestinal absorption of zinc were measured. Calves and rats were fed diets low in zinc, and zinc availability was the percentage increase of zinc in plasma with dietary supplementation of zinc. Availabilities of zinc supplied as zinc chloride, zinc sulfate, zinc oxide, and zinc carbonate were comparable in both calves and rats. Elevated amounts of dietary calcium as ground limestone reduced absorption of zinc in rats fed soy-protein but had no effect on absorption of zinc in the lactating cow. Thus, for cows consuming large amounts of calcium, an increase in the concentration of zinc beyond 40 ppm of the diet appears unnecessary.

Animals↗

PubMed1990

Aspartyl- and glutamyl-lysine crosslinks formation and their nutritional availability.

Transglutaminase-catalyzed incorporation of L-lysine into wheat gliadin rendered the lysine-fortified protein poorly digestible in the in vitro tests. In rat feeding tests, however, the luminal leavings and excreta collected after administration of the [14C]lysine-fortified gliadin contained less than one-tenth of the radioactivity originally administered to rats. The enzymes, gamma-glutamylamine cyclotransferase and 5-oxoprolinase, known to occur in animal kidney are at least in part responsible for the observed high availability of isopeptide bound lysine. A novel enzyme which is capable of directly hydrolyzing the cross-linked isopeptide into component amino acids and peptides, "N epsilon-(gamma-glutamyl)lysine hydrolase" was found in the isolated microorganisms which can use the synthesized N epsilon-(gamma-glutamyl)lysine as their only source of carbon and nitrogen. The enzyme(s) appear to be effectively used for improving digestibility and availability of protein matrixes formed in normal metabolism and by heat and/or shear treatment commonly used in food processing.

Animals↗

PubMed1998

Fermentation of soybean flour with Aspergillus usamii improves availabilities of zinc and iron in rats.

Soybean flour was fermented with Aspergillus usamii to improve the availabilities of dietary zinc and iron through the degradation of phytate. Three kinds of experimental diets that differed in protein sources were prepared: one consisting of 40% fermented soybean flour (RS diet), one consisting of 40% fermented soybean flour (FS diet), and one consisting of 20% regular soybean flour and 20% fermented soybean flour (RF diet). Zinc solubilities in the upper and the lower segments of the small intestine were higher in rats fed the FS diet than in rats fed the RS diet. The FS group showed higher solubility of iron in the lower small intestine than the RS group did. Zinc concentrations in the femur and plasma and iron concentrations in the liver and plasma were higher in the FS group than in the RS group. These results suggested that the fermentation of soybean flour improved the availabilities of dietary zinc and iron, which may be induced by increasing the solubilities of these minerals in the small intestine through the reduction of phytate content. Femoral and plasma zinc concentrations in the RF group were higher than in the RS group, but lower than in the FS group. No difference was noted in liver and plasma iron concentrations between the RF group and the FS group. Although phytase activity in FS degrades phytate in the RF diet, higher activity may be needed to degrade phytate completely.

Animals↗

PubMed1980

A chick assay for availability of lysine in wheat.

A chick growth assay was developed to estimate the availability of lysine in cereal grains. Amino acids were supplied in the basal assay diet by hydrolyzed-feather meal, gelatin, and crystalline amino acids. Dietary nitrogen levels were equalized for all assay diets by adjustment of glutamic acid content, and dietary energy levels were equalized by adjustment of the proportions of corn starch, corn oil, and cellulose. The assay method was tested for validity with two wheat cultivars, using dietary lysine level or lysine intake as the independent variable and weight gain or carcass nitrogen gain as the dependent variable. Taking lysine level as the independent variable did not satisfy statistical tests for validity of the assay procedure. Availability of lysine determined by the selected method of regression of weight gain on lysine intake was .79 (with 95% fiducial limits of .94 and .66) and .76 (.87 and .66) for Manitou and Pitic cultivars, respectively.

Animals↗

PubMed1980

Availability of phosphorus from ammonium polyphosphate for growing chickens.

Phosphorus from ammonium polyphosphate was equivalent in availability to that of other phosphate sources commonly used in broiler rations, and it was more available than that from reagent-grade tricalcium phosphate. Two three-week experiments conducted with broiler chickens showed that growth rate, feed efficiency, viability, and bone calcification were improved to a similar extent by adding an equivalent increment of phosphorus from dicalcium phosphate, defluorinated phosphate, or ammonium polyphosphate. The results of these experiments suggest that ammonium polyphosphate may be a useful phosphorus supplement for practical poultry rations.

Animals↗

PubMed1981

Factors influencing the assessment of the availability of choline in feedstuffs.

Experiments were conducted to test the hypothesis that chicks fed diets designed to be first-limiting in choline will also respond to supplements of sulfur-containing amino acids and that the growth response of chicks fed a choline-limiting diet to a supplement of a feedstuff cannot be accepted as a reliable measure of the choline content of the feedstuff. Chicks fed 25% isolated soybean protein (ISP) diets that were severely limiting in choline showed a growth response to supplements of either choline or methionine. A bioassay was used to determine the availability of choline in soybean meal (SBM). Results indicated that including 10% SBM in the 25% ISP diet (at the expense of corn starch) drastically altered the chicks' response to choline. When 100 ppm choline was added to the 10% SBM diet, growth responses, compared to the original standard curve, indicated recoveries of 400 and 352% in two experiments. Additional studies indicated that chicks fed the 25% ISP + 10% SBM-based diet responded not only to choline additions but also to methionine, cystine, sulfate, and betaine additions. Further, it was shown that chicks fed a practical-type corn-soy-grease-based diet respond equally as well to supplements of 1% concentrated Steffens Filtrate, .2% L-methionine, or 800 ppm choline. The validity of assays of choline availability based on the assumption that choline is the first-limiting nutrient is questioned.

Animal Feed↗

PubMed1983

Biological availability of selenodicysteine in chicks.

The biological availability of selenium (Se) in selenodicysteine (SDC) for chicks was evaluated using plasma glutathione peroxidase (SeGSHpx) activity and tissue Se levels as criteria. In each of two trials day-old Single Comb White Leghorn chicks were fed a basal diet low in Se but supplemented with vitamin E during Days 1 to 14. On Day 15 three replicate groups of eight chicks were assigned to each dietary treatment. Dietary treatments consisted of feeding the basal diet alone or supplemented with approximately 50, 100, or 150 ppb Se as either sodium selenite or SDC from Days 15 to 27. Pooled samples of blood, liver, and breast muscle were obtained from four chicks per replicate group on Day 27. Activity of SeGSHpx and the concentration of Se in plasma, whole blood, muscle, and liver were highly correlated (P less than .0001) with supplemental dietary Se. In Trial 1 no differences were observed between the slopes for each compound upon determining linear regression equations for SeGSHpx, plasma Se, whole blood Se, muscle Se, or liver Se versus supplemental dietary Se. In Trial 2 there were no differences between the slopes for each compound in equations for SeGSHpx, plasma Se, or whole blood Se versus supplemental dietary Se. The ratio of slopes (SDC/sodium selenite) was .82 for both muscle Se and liver Se versus dietary Se. Thus, data indicate that Se in SDC is highly available for chicks.

Animals↗

PubMed1987

Phosphorus availability bioassay using bone ash and bone densitometry as response criteria.

Two experiments were conducted to examine the relative precision of bone densitometry and bone ash methodologies as response criteria in measurement of bioavailability of phosphorus from various supplements for turkeys. Multivariate analyses of variance were used to analyze data collected. Coefficients of correlation and variation and F ratios were used for evaluation. Bone densitometry with one scan at each of 3 points on the bone was faster than bone ash and as precise as bone ash analysis in measuring phosphorus availability in turkeys. The coefficient of correlation between percentage ash (of dry bone) and scan density (milligrams per centimeter length of bone) measurements for treatment effects was .986. The coefficient of variation was about the same for the bone ash (5.8) and the three-point bone scan (6.9) methods. As indicated by the F ratio for testing treatment effects, bone densitometry was better able to detect differences among phosphorus sources. A technician may scan 50 cleaned bones in 3 hr, but with the bone ash method, drying, ashing, and weighing may require 3 working days. Bone sampling technique, multiple operators, different bone sizes, and decay of iodine source were the major factors affecting precision of the bone densitometry technique. Relative biological availabilities of phosphorus from various supplements were about the same by the two methods.

Animals↗

PubMed1990

Effects of particle size on the biological availability of calcium and phosphorus in defluorinated phosphate for chicks.

A total of 576 d-old, male, broiler chicks were used in two trials 1) to determine the range of Ca and P levels over which the response in bone characteristics is linear and 2) to determine the influence of particle size of defluorinated rock phosphate (DFP) on the bioavailability of Ca and P in DFP. Six treatments were used in Experiment 1 in which varying percentages of added Ca (.00, .06, .12, .24, .36, and .48%) and added P (.00, .05, .10, .20, .30, and .40%) were evaluated in a corn-soybean meal diet containing 23% CP, .47% Ca, and .39% P (.14% available P). Weight gain, feed intake, and tibia breaking strength increased (P less than .001) with increasing levels of dietary Ca and P. Treatments in Experiment 2 consisted of: 1) Diet 1, a corn-soybean meal basal diet (23% CP, .50% Ca, .46% P, .21% available P), 2) Diet 1 with .12% added Ca from calcium carbonate (CC) and .07% added P from monosodium phosphate (MSP), 3) Diet 1 with .24% added Ca from CC and .14% added P from MSP; and 4 to 8), Diet 1 with .24% added Ca and .14% added P from five particle sizes of DFP. Feed intake, weight gain, and tibia breaking strength and ash percentage increased linearly (P less than .01) and feed:gain ratio decreased quadratically (P less than .10) with increasing percentages of added Ca and P in Diets 1 to 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

The nutritive value of dietary fats in relation to their chemical composition. Apparent fat availability and metabolizable energy in two-week-old chicks.

Broiler chicks at 2 wk of age were fed the following fats and oils at 4% in a corn-wheat-soybean basal diet: palm oil (PO); tallow (T1 and T2); tallow + soybean oil (50:50, TSO); tallow+acidulated soybean oil soapstock (50:50, TASO); soybean oil (SO); and linseed oil (LO). All of these, with the exception of T1, contained 5% soybean lecithin. The apparent fat availability (AFA) and AME of added fats ranged from 78.8 to 96.0% and from 7.32 to 8.95 kcal/g, respectively. Three fat sources (TSO, SO, and LO) resulted in the highest values for these two measurements, whereas PO, T1, T2, and TASO showed the lowest values. There was no difference for AME of diets among fat-supplemented treatments, regardless of the difference in the nutritive values of the fats and oils tested. The apparent availability of each fatty acid (AAFA) for C16:0, C18:0, C18:1, C18:2, and C18:3 was calculated from the analysis of the diets and excreta collected over a 4-d period. The results of the present study indicated that 2-wk-old chicks utilize TSO, SO, and LO more efficiently than PO, T1, T2, and TASO.

Animal Nutritional Physiological Phenomena↗

PubMed1995

Metabolizable energy and amino acid availability of full-fat seeds, meals, and oils of flax and canola.

The TME, true amino acid availability (TAAA), AME, and apparent amino acid availability (AAAA) were determined in full-fat seeds, meals, oils, and meal-oil mixtures of flax and canola using Single Comb White Leghorn roosters by the force feeding and total excreta collection assay. The metabolizable energy values were corrected to zero nitrogen balance to obtain AMEn and TMEn. The AMEn and TMEn contents of canola seed (4.46 and 4.56 kcal/g) were respectively higher (P < .05) than those of flax seed (3.75 and 3.75 kcal/g). Flax meal contains contents of AMEn (2.07 kcal/g) and TMEn (2.07 kcal/g) similar to those (1.98 and 2.09 kcal/g) of canola meal. There were no differences in AMEn and TMEn values between flax oil (8.10 and 8.28 kcal/g) and canola oil (8.25 and 8.46 kcal/g). No differences were observed among AME, AMEn, TME, and TMEn values within each test ingredient except canola meal: its TME value was higher (P < .05) than its AMEn value. The TAAA values were higher for full-fat seeds than for the meals and also higher for canola seed and meal than for flax seed and meal. The AAAA values, although lower than TAAA values, followed similar patterns as TAAA values. Both AAAA and TAAA values were higher when the ingredients were fed with a basal diet than when fed alone.

Amino Acids↗

PubMed1996

Availability for poults of phosphorus from meat and bone meals of different particle sizes.

Two experiments were conducted to compare the dietary availability of P from meat and bone meal (MBM) with that of P from dicalcium phosphate (DP) for poults. Two batches of the same MBM were tested. The batches differed in fineness of grind; one was passed through a 10-mesh screen (openings of 2.03 mm) (MBM1O) and the other through a 12-mesh screen (openings of 1.91 mm) (MBM12). In Experiments 1 and 2, the low-P basal diets contained, by analysis, 0.54% P (0.2% nonphytate P) and 0.64% P (0.3% nonphytate P), respectively. Each batch of MBM and DP were included in isocaloric, equinitrogenous diets to obtain increments of 0.1, 0.2, 0.3, and 0.4% P added to the basal diet. Three pens, each containing seven poults, were assigned to each of the 13 dietary treatments. Poults were fed the diets from 5 to 11 and 6 to 13 d of age in Experiments 1 and 2, respectively. Regression analyses of the data showed that increases in BW and tibia ash were linearly related (P </= 0.01) to percentage dietary P and to quantity of P consumed. Common intercept multiple linear regression was used to derive relative availabilities (RA) with DP assigned a value of 100. On the basis of BW gains, RA of MBM1O and MBM12 ranged from 99.1 to 105.5, depending on the independent variable and the experiment. Similarly, on the basis of tibia ash, RA ranged from 97.3 to 104.8. None of the RA differed (P > 0.05) from 100. Thus, the RA of P from MBM tested were equal to that of P from DP, and particle size of the MBM did not affect RA of P.

Animals↗

PubMed2000

Mechanism of oxygen availability from hydrogen peroxide to aerobic cultures of Xanthomonas campestris.

Fundamental studies on the availability of oxygen from the decomposition of H(2)O(2), in vivo, by Xanthomonas campestris, when H(2)O(2) is used as an oxygen source are presented. It was found that the H(2)O(2) added extracellularly (0.1-6 mM) was decomposed intracellularly. Further, when H(2)O(2) was added, the flux of H(2)O(2) into the cell, is regulated by the cell. The steady-state H(2)O(2) flux into the cell was estimated to be 9.7 x 10(-8) mol m(-2) s(-1). In addition, it was proved that the regulation of H(2)O(2) flux was coupled to the protonmotive force (PMF) using experiments with the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP), which disrupts PMF. The coupling constant between the rate of free energy availability from PMF and the rate of reduction of H(2)O(2) flux, was found to be 46.4 mol m(-2) s(-1) J(-1) from simulations using a developed model. Also, the estimated periplasmic catalase concentration was 1.4 x 10(-9) M.

Aerobiosis↗

PubMed2001

Chemical and biological availability of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl.

This study examined the chemical and biological availability of two nonpolar organic compounds, benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP), from a spiked sediment that was aged for varying amounts of time. Chemical availability was evaluated using four different solvent combinations to extract chemicals from the sediment. The extractability of BaP and HCBP from sediment using traditional solvents was then compared to the transfer efficiency (TE) of a benthic invertebrate (Lumbriculus variegatus) to relate chemical extractability to bioavailability in the organisms. Results indicated that water was the solvent that best approximated bioavailability for BaP, whereas comparisons for HCBP were inappropriate, because TE values exceeded 100%. The inability to obtain a reasonable TE estimate for HCBP was most likely due to the fact that the oligochaetes received a major portion of their uptake from interstitial water instead of ingestion of sediment particles, which invalidated an important assumption of the TE model. Overall, the results of this study indicate that exhaustive chemical extractions may be an inaccurate representation of the bioavailable fractions for some contaminants.

Animals↗

PubMed1975

Availability of phendimetrazine from sustained and non-sustained action formulations.

Two tablet formulations of d-phendimetrazine bitartrate, Obex (35 mg non-sustained action) and Obex-LA (105 my sustained action), were compared in terms of biological availability in 9 volunteers on the basis of serum level findings. The ratio of the areas under the absorption and elimination curves was 1:2,2 (Obex:Oves-LA), indicating that the biological availability of phendimetrazine from Obex-LA was plus or minus 70% of that from Obex. The elimination half-life of phendimetrazine was found to be 9,1 hours. An evaluation of appetite suppression revealed that the two formulations were equally effective at breakfast and at dinner, with Obex-LA significantly superior to Obex at lunch.

Adult↗

PubMed2000

Effect of drug solubility on the in vitro availability rate from suppositories with lipophilic excipients.

The factors involved in mechanisms of availability of different drugs from suppositories with lipophilic excipients were studied by using an in vitro model of the rectal compartment with a porous membrane simulating the rectal barrier. The solubility in water of drugs was found to be the fundamental factor influencing the release rate from suppositories. In fact, following the melting of the suppository at body temperature the drug particles can migrate to the interface with the small volume of rectal secretion where they dissolve. Drug molecules can so diffuse until they come into contact with the rectal barrier through which the drug is absorbed. Drug concentration in the intrarectal aqueous phase produces the gradient against the large volume of the plasma phase. This gradient regulates the diffusion rate through the barrier. A drug with a low water solubility saturates the intrarectal phase at low concentration hindering the subsequent dissolution of the drug particles remaining in the melted excipient. This fact maintains the viscosity of the melted suppository at a ligh level, which slows the migration of the particles. On the other hand, a drug with high water solubility quickly leaves the excipient, producing a high concentration in the intrarectal phase which supports a high diffusion rate across the barrier. The results obtained indicate that drugs with low solubility in water result in low availability, while drugs with good solubility can give an intense and rapid drug supply for a rapid and intense therapeutic response with the dose administered almost completely utilised.

Administration, Rectal↗