Effect of phytate on element bioavailability in the second generation of rats

In this paper the relation between long term consumption of a high dose of sodium phytate and the mineral status of the organism is evaluated in rats. For this purpose, element concentrations (Ca, Mg, Fe, Zn, Mn) were determined in liver, heart, testicle, bone and urine of a second generation of Wistar rats, treated with a phytate free diet (AIN-76A) and with the same diet plus 1% phytate as sodium salt. The most significant differences were observed between bone zinc contents of male and female rats. The zinc content of rats fed a 1% phytate as sodium salt diet resulted clearly lower than that found in no-phytate treated rats. Hence, it is concluded that when up to 1% of phytate as sodium salt is consumed together with an equilibrated purified diet (free of phytate), no decrease in mineral bioavailability is observed in second generation rats, except for an indication of lower zinc availability by lower zinc concentrations in some organs, mainly bone. However, using this purified diet, the zinc concentration in bone resulted around 10 times higher than found in rats fed with a common non purified rat chow.

Quantitative liver-spleen scan using single photon emission computerized tomography (SPECT) for assessment of hepatic function in cirrhotic patients

BACKGROUND/AIMS

Accurate quantitative determination of liver function is critical in cirrhotic patients in order to predict outcome, particularly in patients who undergo hepatic resection or non-hepatic surgery. As colloid uptake by perfused Kupffer cells is proportional to perfused hepatocyte mass, quantitative liver spleen scan may be used as an index of perfused hepatocyte mass. Thus, this study was conducted to evaluate quantitative single photon emission computerized tomography (SPECT) of Tc-99mm-phytate colloid uptake by the liver as a test for hepatic function in cirrhotic patients.

METHODS

Quantitative SPECT was used to measure liver volume, quantitative colloid uptake by the liver and percentage of injected dose/ml of liver tissue in cirrhotic patients (n=75), non-cirrhotic patients with chronic liver disease (n=52) and patients without liver disease (n=36).

RESULTS

Although liver volume was similar among the three groups, the cirrhotic patients had significantly lower total quantitative uptake and quantitative uptake/ml compared to groups 2 and 3 (P<0.001). Quantitative liver uptake in the cirrhotic patients was highly correlated with Child-Pugh score (r=-0.64, P<0.0001) and with indocyanine green retention at 15 min (r=-0.84, P<0.0001).

CONCLUSIONS

Quantitative SPECT of the liver may be an additional, useful, non-invasive quantitative test for assessment of hepatic function and severity of liver disease in cirrhotic patients.

Genetics of phytate phosphorus bioavailability: heritability and genetic correlations with growth and feed utilization traits in a randombred chicken population

The current study was undertaken to estimate variance components for phytate P bioavailability (PBA) and the genetic correlations among PBA with growth and feed utilization (or intake) traits in an unselected random mating chicken population. Pedigreed data from 901 Athens-Canadian randombred chickens hatched from 26 sires, 71 dams, and 105 grandparents were used for estimation of genetic parameters. Birds were individually housed in metabolic cages at 4 wk of age and fed a 0.35% P diet. After 3 d of acclimatization, excreta produced for 3 consecutive d were collected and feed consumed (FC) was measured. Individual 4-wk BW and BW gain (BWG) during the 3-d excreta collection period were also measured. Feed conversion ratios (FCR) were calculated. Phytate P bioavailability was estimated from the disappearance of phytate during the passage of feed through the gastrointestinal tract. The restricted maximum likelihood method with the average information matrix algorithm was used for the estimation of variance components. The heritability estimate for PBA was about 0.10. Genetic correlations between PBA and BW, BWG, and FC were moderate and negative, indicating that improving PBA utilization would moderately affect growth. The genetic correlation between PBA and FCR was negligible and suggested that selection for PBA will not adversely affect FCR. The economic implications of genetically modifying poultry to improving phytate P utilization and the subsequent elimination or reduction of the amount of phytase used in poultry diets are yet to be determined.

Hydrolysis of phytic acid and its availability in rabbits

Twenty weaned rabbits were fed ad libitum two granulated feeds containing lucerne meal, barley, oats, wheat bran, oilseed meals and sugarbeet pulp in different proportions. Phytate P in these feeds represented 28.6 and 29.3 % of the total P. Digestibility trials were carried out in rabbits 7 and 10 weeks old. Digestibility of phytate P was 82.1 %, on average. Apparent digestibility of total P was 48.1 and 35.5 % in rabbits aged 7 and 10 weeks, respectively. Concentration of P in the faecal DM of these rabbits averaged 11.9 and 14.7 mg/g. Most of the faecal P was phosphates P (68.1 %). Proportion of phytate P in total faecal P was 9.0 %. Age effect on total P digestibility and faecal P concentration was significant (P<0.05). In five in vitro experiments twenty-four rabbits were killed at the age of 11 weeks, digesta samples diluted with physiological saline containing phytic acid and incubated anaerobically. Calculations of phytase activity in segments of the digestive tract were based on the estimation of phytic acid hydrolysed during the first 2 h of incubation. The caecum contained 58.6 % of the phytase activity of the digestive tract. Corresponding relative values for the phytase activity in the stomach, small intestine and colon were 22.3, 7.7 and 11.4 %, respectively. In incubations of the caecal contents, phytic acid was hydrolysed more rapidly at pH 5-6 than in the neutral pH region. The hydrolysis was inhibited by Ca cations, and to a small extent also by phosphate anions. Commercial fungal phytase (Natupho) was highly active in incubations of the contents of the stomach at pH 1.9. It can be concluded that phytic acid is hydrolysed quite efficiently in the digestive tract of rabbits. This hydrolysis occurred mainly in the caecum. Absorption of soluble inorganic phosphates in the gut is incomplete.

Transport of the highly charged myo-inositol hexakisphosphate molecule across the red blood cell membrane: a phase transfer and biological study

To address the problem of delivering highly charged small molecules, such as phytic acid (InsP(6) or IHP), across biological membranes, we investigated an approach based on a non-covalent interaction between transport molecule(s) and IHP. Thus, we synthesized a collection of compounds containing IHP ionically bound to lipophilic (but non-lipidic) ammonium or poly-ammonium cations. First, we assessed the ability of these water-soluble salts to cross a biological membrane by measuring the partition coefficients between human serum and 1-octanol. In view of the ability of IHP to act as potent effector for oxygen release, the O(2)-hemoglobin dissociation curves were then measured for the most efficient salts on whole blood. From both the biological and the physical properties of IHP-ammonium salts we determined that cycloalkylamines (or poly-amines) were the best transport molecules, especially cycloheptyl- and cyclooctylamine. Indeed, the octanol/serum partition coefficient of IHP undecacyclooctylammonium salt, is superior to 1, which is very favorable for potential uptake into the red blood cell membrane. A qualitative correlation was found between the partitioning experiments and the biological evaluations performed on whole blood.

Effects of exogenous inositol hexakisphosphate (InsP(6)) on the levels of InsP(6) and of inositol trisphosphate (InsP(3)) in malignant cells, tissues and biological fluids

InsP(6) is abundant in cereals and legumes. InsP(6) and lower inositol phosphates, in particular InsP(3), participate in important intracellular processes. In addition, InsP(6) possess significant health benefits, such as anti-cancer effect, kidney stones prevention, lowering serum cholesterol. Because of the insensitivity of existing methods for determination of non-radiolabeled inositol phosphates, little is known about the natural occurrence, much less on the concentrations of InsP(6) and InsP(3) in biological samples. Using gas chromatography-mass detection analysis of HPLC chromatographic fractions, we report a measurement of unlabeled total InsP(3) and InsP(6) (a) as they occur within cells culture, tissues, and plasma, and (b) their changes depending on the presence of exogenous InsP(6). When rats were fed on a purified diet in which InsP(6) was undetectable (AIN-76A) the levels of InsP(6) in brain were 3.35 +/- 0.57 (SE) micromol.kg(-1) and in plasma 0.023 +/- 0.008 (SE) micromol.l(-1). The presence of InsP(6) in diet dramatically influenced its levels in brain and in plasma. When rats were given an InsP(6)-sufficient diet (AIN-76A + 1% InsP(6)), the levels of InsP(6) were about 100-fold higher in brain tissues (36.8 +/- 1.8 (SE)) than in plasma (0.29 +/- 0.02 (SE)); InsP(6) concentrations were 8.5-fold higher than total InsP(3) concentrations in either plasma (0.033 +/- 0.012 (SE)) and brain (4.21 +/- 0.55 (SE)). When animals were given an InsP(6)-poor diet (AIN-76A only), there was a 90% decrease in InsP(6) content in both brain tissue and plasma (p < 0.001); however, there was no change in the level of total InsP(3). In non-stimulated malignant cells (MDA-MB 231 and K562) the InsP(6) contents were 16.2 +/- 9.1 (SE) micromol.kg(-1) for MDA-MB 231 cells and 15.6 +/- 2.7 (SE) for K 562 cells. These values were around 3-fold higher than those of InsP(3) (4.8 +/- 0.5 micromol.kg(-1) and 6.9 +/- 0.1 (SE) for MDA-MB 231 and K562 cells respectively). Treatment of malignant cells with InsP(6) resulted in a 2-fold increase in the intracellular concentrations of total InsP(3) (9.5 +/- 1.3 (SE) and 10.8 +/- 1.0 (SE) micromol.kg(-1) for MDA-MB 231 and K562 cells respectively, p < 0.05), without changes in InsP(6) levels. These results indicate that exogenous InsP(6) directly affects its physiological levels in plasma and brain of normal rats without changes on the total InsP(3) levels. Although a similar fluctuation of InsP(6) concentration was not seen in human malignant cell lines following InsP(6) treatment, an increased intracellular levels of total InsP(3) was clearly observed.

Studies on the efficacy of cholecalciferol and derivatives for stimulating phytate utilization in broilers

Studies were conducted to determine the effect of dietary supplementation with cholecalciferol (D3), 1,25-dihydroxycholecalciferol [1,25-(OH)2D3], 1alpha-hydroxycholecalciferol (1alpha-OHD3), and 25-hydroxycholecalciferol (25-OHD3) on utilization of phytate P by broiler chickens. Three experiments were conducted with corn-soybean meal type diets with D3 and 1,25-(OH)2D3 being tested in one experiment and 1,25-(OH)2D3, 1alpha-OHD3, and 25-OHD3 being tested in two experiments of exactly the same design. In the first experiment, high levels of D3 (110 microg and 220 microg/kg of diet) increased phytate P utilization, but the increase was not as great as that obtained from 1,25-(OH)2D3 supplementation. In the other two experiments, 1,25-(OH)2D3, D3 and 1alpha-OHD3 were consistently effective in increasing phytate P utilization as measured by plasma Ca and P, incidence of P rickets, bone ash, and retention of Ca, P, and phytate P. Supplementation with 25-OHD3 in general gave smaller and more inconsistent responses to these criteria, indicating some inconsistency in its ability to improve phytate P utilization.

Effect of mitomycin-C on the bioavailability of the radiopharmaceutical (99m)technetium-phytic acid in mice: a model to evaluate the toxicological effect of a chemical drug

The many desirable characteristics of technetium-99m ((99m)Tc) have stimulated the development of labelling techniques for different molecular and cellular structures. It is generally accepted that a variety of factors can alter the biodistribution of radiopharmaceuticals and one such factor is drug therapy. Because patients on chemotherapeutic treatment receive a radiopharmaceutical in a nuclear medicine procedure, we have studied in Balb/c mice the effect of mitomycin-C on the biodistribution of the radiopharmaceutical (99m)Tc-phytic acid ((99m)Tc-PHY) used in hepatic scintigraphy. Mitomycin-C is an antineoplastic agent obtained from Streptomyces caesptosus and is used on the treatment of disseminated adenocarcinoma of the stomach or pancreas. Three doses of mitomycin-C were administered via the ocular plexus into Balb/c mice. One hour after the last dose, (99m)Tc-PHY was administered and the animals were sacrificed. The organs were isolated, the radioactivity was determined in a well counter and the percentages of radioactivity in the organs were calculated. The results have shown that the percentage radioactivity has been increased in stomach, spleen, lung, thyroid and bone, decreased in pancreas and thymus and not altered in ovary, uterus, kidney, heart, liver and brain. The changes in the distribution of (99m)Tc-PHY may be the result of metabolic processes and/or therapeutic actions produced by the administration of mitomycin-C.

Hydrolysis of phytic acid by intrinsic plant and supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re-entrant cannulas. 3. Hydrolysis of phytic acid (IP6) and occurrence of hydrolysis products (IP5, IP4, IP3 and IP2)

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (Aspergillus niger) were investigated with six minipigs (40-50 kg initial body weight) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5 and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2 and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet [43 U phytase/kg dry matter (DM)]; (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM); and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 07 30 h and 19 30 h, each animal was fed 350 g diet mixed with 1050 ml de-ionized water. Digesta were collected continuously and completely during a 12-h period after feeding. Mean hydrolysis rates of IP6 in the stomach as measured at the proximal duodenum of animals 1, 4, 5 and 6 were 9.0, 77.2 and 66.2% for diet 1, 2 and 3, respectively. Microbial phytase was much more effective in phytate hydrolysis than wheat phytase. Mean IP6 hydrolysis rates of the respective diets in the stomach and small intestine as measured at the distal ileum of animals 1, 2 and 3 were 19.0, 62.6 and 64.6% and were lower than treatment means of the stomach only. Differences existed between experimental animals with respect to their ability to hydrolyse IP6 in the stomach independent of the presence and source of dietary phytase. Considerable amounts of hydrolysis products occurred in both the duodenal and ileal digesta when diets 2 and 3 were fed; however, only traces were determined after ingestion of diet 1. Independent of dietary treatment, four IP5 isomers were detected, but in different amounts.

A home-based method to reduce phytate content and increase zinc bioavailability in maize-based complementary diets

This study aimed to develop and assess the feasibility of a home-based method to reduce the phytate content of maize and improve zinc bioavailability from maize-based complementary diets in rural Malawi. A method of extracting phytate through the soaking of pounded maize was developed, and found to reduce phytate content to 49% of unrefined maize. An educational program was used to teach the processing method to mothers of children receiving complementary foods in rural Malawian communities. Samples of maize flour prepared by this process by participants were collected and analysed for phytate and zinc content. Of these, 70% of samples were found to be adequately prepared; mean phytate content of these samples was 48% of unprocessed, unrefined maize flour controls. Most participants found the cooked product to have an acceptable taste (99%) and texture (68%), and felt the processing method took little or no extra time (86%) and was culturally acceptable (96%). The phytate and zinc content of the processed maize flour samples analysed from community prepared samples was substituted into the dietary analysis of complementary foods for 9- to 11-month-old children (n = 31). The bioavailability of zinc from the complementary diet would predict an increase from low (24%) to moderate (33%) levels.

Absorption and excretion of orally administered inositol hexaphosphate (IP(6) or phytate) in humans

A study of the pharmacokinetic profile (oral absorption and renal excretion) of inositol hexaphosphate or phytate (IP(6)) is presented. Seven healthy volunteers were following a IP(6) poor diet (IP(6)PD) in a first period, and on IP(6) normal diet (IP(6)ND) in a second one. When following the IP(6)PD they become deficient in IP(6), the basal levels found in plasma (0.07+/- 0.01 mg/L) being clearly lower than those found when IP(6)ND was consumed (0.26+/- 0.03 mg/L). During the restriction period the maximum concentration in plasma were obtained 4 h after the ingestion of a single dose of IP(6), observing almost the same renal excretion profiles for the three different commercial sources and doses. After the IP(6) restriction period, volunteers were on IP(6)ND, reaching normal plasma and urinary IP(6) values in 16 days. Thus, the normal plasma and urinary concentrations, can be obtained either by consumption of a IP(6)ND taking a long time or in a short period by IP(6) supplements.

Dietary phytate and mineral bioavailability

The relation between the dietary phytate (InsP6), mineral status and InsP6 levels in the organism, using three controlled diets (AIN-76A, AIN-76A + 1% phytate, AIN-76A + 6% carob seed germ), are studied. AIN-76A is a purified diet in which InsP6 is practically absent. No important or significant differences in the mineral status (Zn, Cu, Fe) of blood, kidneys, liver, brain and bone, were observed, except iron in the brain. Thus, the amounts of iron found in the brain of rats fed AIN-76A + 1% InsP6 were significantly inferior to those found in rats fed AIN-76A diet. The amounts of InsP6 found in organs of rats fed AIN-76A diet became very low or even undetectable while the ones found in rats fed diets that contained 1% and 0.12% (AIN-76A + 6% carob seed germ) InsP6, were considerably higher and similar. Moreover the majority of rats fed AIN-76A diet exhibited calcifications at the corticomedullary junctions, whereas no calcifications were detected in rats fed the other two diets. From these results, it can be deduced that there was no important adverse effects on mineral status as a consequence of the presence of InsP6 in the studied diets. Besides, considering that a 0.12% InsP6 contained in the AIN-76A purified diet through the addition of a 6% of carob seed germ to this diet, produced the same beneficial effects as the direct addition of a 1% of InsP6 and no negative effects on mineral status was observed, it can be concluded that the value of the presence of InsP6 at adequate amounts in the diet is remarkable and must be favourably considered.

New property of vitamin A and beta-carotene on human iron absorption: effect on phytate and polyphenols as inhibitors of iron absorption

One hundred and seventy four human subjects were studied to find out the interaction of vitamin A or beta-carotene with the inhibitors of iron absorption, from a basal breakfast containing bread from either 100 g of precooked corn flour or 100 g of white wheat flour, 50 g of cheese and 10 g of margarine. Bread was labeled with either 55Fe or 59Fe. This bread was made from commercially flours fortified with iron as ferrous fumarate and vitamins. It was noticed that the percentage of iron absorption from the breakfast prepared with precooked corn flour given alone and with different concentrations of coffee was practically the same, while the iron absorption from the breakfast prepared from wheat flour decreased from 6% when the breakfast was given alone, to less than 2% when it was given with different concentrations of coffee. The only ingredient present in precooked corn flour and not in wheat flour was vitamin A. This difference encouraged the authors to perform further experiments using precooked corn and wheat flours fortified only with ferrous fumarate. These studies demonstrated that vitamin A inhibits the effect of the polyphenol and partially inhibits the effect phytate on iron absorption. HPLC and spectrophotometric studies demonstrated an interaction between vitamin A and iron. Other experiments, which included 100 volunteers, were performed to test the effect of vitamin A and beta-carotene on iron absorption from corn, wheat and rice. The presence of vitamin A increased iron absorption up to 3 times for rice, 2.4 times for wheat and 1.8 times for corn. beta-carotene increased absorption almost 3 times for the three cereals tested, showing that both compounds were capable of preventing the inhibitory effect of phytates on iron absorption. This information suggest that vitamin A and beta-carotene form a complex with iron keeping it soluble in the intestinal lumen and preventing the inhibitory effect of phytates and polyphenols on iron absorption.

The effects of citric acid on phytate-phosphorus utilization in young chicks and pigs

Several bioassays were conducted with young chicks and pigs fed phosphorus (P)-deficient corn-soybean meal diets. With diets for chicks containing .62% Ca and .42% P (.10% available P), graded doses of a citric acid + sodium citrate (1:1, wt:wt) mixture (0, 1, 2, 4, or 6% of diet) resulted in linear (P < .01) increases in both weight gain and tibia ash. Relative to chicks fed no citric acid, tibia ash (%) and weight gain (g/d) were increased by 43 and 22%, respectively, in chicks fed 6% citric acid. Additional chick trials showed that 6% citric acid alone or sodium citrate alone was as efficacious as the citric acid + sodium citrate mixture and that 1,450 U/kg of phytase produced a positive response in bone ash and weight gain in chicks fed a diet containing 6% citrate. Varying the Ca:available P ratio with and without citrate supplementation indicated that citric acid primarily affected phytate-P utilization, not Ca, in chicks. Moreover, chicks did not respond to citrate supplementation when fed a P-deficient (.13% available P), phytate-free casein-dextrose diet. Young pigs averaging 10 to 11 kg also were used to evaluate citric acid efficacy in two experiments. A P-deficient corn-soybean meal basal diet was used to construct five treatment diets that contained 1) no additive, 2) 3% citric acid, 3) 6% citric acid, 4) 1,450 U/kg phytase, and 5) 6% citric acid + 1,450 U/kg phytase. Phytase supplementation increased (P < .01) weight gain, gain:feed, and metatarsal ash, whereas citric acid addition increased only gain:feed (P < .05) and metatarsal ash (P < .08). A subsequent 22-d pig experiment was conducted to evaluate the effect of lower levels of citric acid (0, 1, 2, or 3%) or 1,450 U/kg phytase addition to a P-deficient corn-soybean meal diet. Phytase supplementation improved (P < .01) all criteria measured. Weight gain and gain:feed data suggested a response to citric acid addition, but this was not supported by fibula ash results (P > .10). The positive responses to phytase were much greater than those to citric acid in both pig experiments. Thus, dietary citric acid effectively improved phytate P utilization in chicks but had a much smaller effect in pigs.

A new phytase expressed in yeast effectively improves the bioavailability of phytate phosphorus to weanling pigs

We have recently expressed a new phytase enzyme in a yeast system. Three experiments with a total of 140 weanling crossbred pigs were conducted to examine the efficacy of this enzyme in improving the bioavailability of phytate-P in corn-soybean meal diets to young pigs. Experiment 1 compared the efficacy of this new phytase with a commercially available phytase (Natuphos, BASF) for 4 wk at an inclusion level of 1,200 U/kg of diet. Experiment 2 compared the responses of pigs to four doses of the new phytase supplementation (300, 600, 900, and 1,200 U/kg of diet) for 4 wk. Experiment 3 compared the efficacy of this new phytase and Natuphos at a marginally optimal dose (700 U/kg of diet) for 5 wk. A group of pigs were fed the P-deficient basal diet as a negative control in Exp. 1, and a group of pigs were fed the basal diet plus .17 or .22% inorganic P as a positive control in all experiments. In Exp. 1, pigs fed the two sources of phytase had similar ADG (564 vs 567 g), gain/feed (.597 vs .589), plasma inorganic P concentrations (8.9 vs 8.4 mg/dL), and mobility scores (4.25 vs 4.46) that were higher (P < .05) than those of the negative control. In Exp. 2, plasma inorganic P concentration was a fairly linear response to the phytase dose (r > .83) at wk 1 and 2. Overall ADG of pigs also tended to increase with the phytase dose (P = .15). In Exp. 3, pigs fed the two sources of phytase had ADG (483 vs 506 g) similar to that of the positive control (508 g). These two groups also had similar plasma inorganic P concentrations (7.7 vs 7.4 mg/dL) that were lower (P < .05) than those of the positive control group (9.7 mg/dL). There was no significant effect of dietary treatments on ADFI in all three experiments. In conclusion, our new phytase was as effective as Natuphos, at the inclusion level of 700 or 1,200 U/kg of a P-deficient, corn-soybean meal diet, in improving phytate-P utilization by young pigs.

Activity of various hydroxylated vitamin D3 analogs for improving phosphorus utilisation in chicks receiving diets adequate in vitamin D3

1. Young chicks were used to evaluate the efficacy of 2 new vitamin D3 analogs relative to 1 alpha-hydroxycholecalciferol (1 alpha-OH D3) for their ability to improve the bioavailability of phytate-bound phosphorus (P) when added to P-deficient maize-soyabean meal diets that were superadequate in cholecalciferol. 2. Both 20-epi-19-nor-1,25-(OH)2 D3 and 20-epi-19-nor-1 alpha-OH D3 were observed to have phytate-P releasing activity, as measured by bone ash responses. 3. However, the bioactivity of the 2 new analogs differed when compared with 1 alpha-OH D3. The 20-epi-19-nor-1 alpha-OH D3 analog had a lower (P < 0.05) phytate-P releasing activity (45%) than either 1 alpha-OH D3 of 20-epi-19-nor-1,25-(OH)2 D3, which did not differ. 4. A dietary concentration of 10 to 15 micrograms/kg 1 alpha-OH D3 was found to optimize phytate-P utilisation in 2-week-old chicks.

Scintigraphic diagnosis of intrathoracic extramedullary hematopoiesis in a patient with beta-thalassemia

We report the scintigraphic diagnosis of intrathoracic extramedullary hematopoiesis (EMH) in a patient with beta-thalassemia. A patient had a mass in the right thoracic paravertebral region on radiography and CT. Bone marrow imaging of the thorax by means of both Tc-99m nanocolloid and phytate demonstrated uptake of the tracer in the mediastinal mass, establishing the diagnosis of EMH.

Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3

Commercial and laboratory-strain crossbred chicks responded (P < .01) markedly to 1alpha-hydroxycholecalciferol (1alpha-OH D3) during the 2nd and 3rd wk of life. Bone-ash responses exceeded 50% when this compound was added at 20 microg/kg to phosphorus (P)-deficient corn-soybean meal diets containing surfeit levels (25 microg/kg) of cholecalciferol (D3). Phosphorus excretion was decreased (P < .01) and, thus, retention was increased (P < .01) when 1alpha-OH D3 was supplemented. A P-deficient (.10% P) casein-amino acid purified diet, devoid of D3, was used to determine whether 15 microg/kg of D3 was sufficient to facilitate optimal absorption of the nonphytate P contained in this diet. Bone ash responded to .075% P addition (KH2PO4), and chicks fed diets with .175% nonphytate P exhibited further bone-ash responses to 15 microg/kg of D3 or 10 microg/kg 1alpha-OH D3. Higher levels of either of these D3 compounds did not produce additional responses. This suggested that 15 to 25 microg/kg of D3 in a P-deficient corn-soybean meal diet (.28% phytate P and .14% nonphytate P) is more than adequate to facilitate optimal absorption of the nonphytate P present in the diet. A P-deficient casein-dextrose diet (.13% nonphytate P and 15 microg/kg D3) was fed in the final chick assay, and chicks fed this diet did not show bone ash responses to 1alpha-OH D3 or to microbial-derived phytase (1,470 units/kg). Thus, with P-deficient corn-soybean meal diets containing at least 15 microg D3/kg, 1alpha-OH D3 supplementation markedly increased weight gain and bone ash because it increased the utilization of phytate P.

Improving phytate phosphorus availability in corn and soybean meal for broilers using microbial phytase and calculation of phosphorus equivalency values for phytase

Two experiments were conducted to determine the effectiveness of Natuphos phytase for improving P availability of soybean meal-based semipurified diets (SP, Experiments 1 and 2) and corn-soybean meal-based diets (CS, Experiment 2) fed to broilers (1 to 21 d). There were 360 and 288 birds fed the SP diets in Experiments 1 and 2, respectively, and 288 birds were fed the CS diets in Experiment 2. Phosphorus equivalency values for phytase were calculated. The basal diets were formulated to contain 0.27% nonphytate P (nP); the SP basal diet contained 0.45% total P (tP) that included 0.17% P as defluorinated phosphate; the CS basal diet contained 0.51% tP that contained 0.12% P as defluorinated phosphate. Both basal diets were supplemented with defluorinated phosphate to provide 0.36, 0.45, of 0.54% nP or with 350, 700, or 1,050 U of phytase/kg diets. Supplementing defluorinated phosphate and phytase linearly increased BW gain (P < 0.001), feed intake (P < 0.001), and percentage ash of dried toes (P < 0.01). Phytase addition increased apparent retention of P (P < 0.02), Ca (P < 0.005 in Experiment 2), and N (P <0.06 in Experiment 2 for CS), increased apparent digestibility of DM (P < 0.04), and linearly decreased (P <0.005) P excretion. In comparison to the 0.45% np diet, P excretion was reduced 42 to 51% by addition of phytase. The addition of defluorinated phosphate linearly decreased apparent retention of P (P < 0.02) and Ca (P < 0.005 in Experiment 2), and increased P excretion (P < 0.007). The average of released P by phytase calculated by solving nonlinear or linear response equations of P and phytase levels for SP diets in Experiments 1 and 2 gave a P equivalency value 1 g P = 1,146 U of phytase. The P equivalency value for CS diets fed only in Experiment 2 was 785 U of phytase = 1 g P as defluorinated phosphate. These studies show that microbial phytase is effective for improving P availability and for decreasing P excretion. Added phytase can also increase Ca and N retention.

Distribution volume of three 99mTc-labeled compounds in the rat liver with time after intraportal and intravenous injections

With the aim of making direct investigational studies of various liver functions of sustained healthy animals, we devised operative procedures which are not only simple and reproducible but also adaptable to experiments even over the course of one-week without anesthesia. Using rats which have been operated upon, three kinds of tracers, 99mTc-pool scinti, 99mTc-pertechnetate and 99mTc-phytate, were recorded by a scintillation camera with a single-photon system immediately after intraportal administration. The results revealed that the discharge of these radioactive components from the hepatic vein began 0.2s after the administration, that the maximum intrahepatic concentration was reached between 2 and 5 s thereafter, and that 10 s later, these radioactive components were returned to the liver after their systemic circulation. Intrahepatic uptake of these three tracers was about 20% for all radioactivities administered.

Calcium level affects the efficacy of supplemental microbial phytase in corn-soybean meal diets of weanling pigs

A 2 x 2 x 2 factorial experiment was conducted with 64 pigs (4 wk old, 8.04 +/- .50 kg BW) to determine the effect of various dietary concentrations of Ca, vitamin D, and microbial phytase (Aspergillus niger) on phytate-P utilization. A low-P, corn-soybean meal diet was supplemented with two levels of phytase (unit/gram), 750 (suboptimal) and 1,200 (optimal); of vitamin D (international unit/kilogram), 660 (normal) and 6,660 (high); and of Ca (percentage), .4 (low) and .8 (normal). Pen feed consumption and individual pig weights, plasma inorganic P and Ca concentrations, and plasma alkaline phosphatase (AP) activity were measured at d 10, 20, and 30. The normal dietary Ca concentration had an adverse effect (P < .05) on all the response measures. The depressive effect of the normal dietary Ca on performance was greater (P < .05) at the normal vitamin D level or at the optimal phytase level than at the other levels of these two factors. The elevation in plasma AP activity in pigs fed the normal dietary Ca was greater (P < .05) at the suboptimal than at the optimal phytase level. The decreases in plasma inorganic P concentration and increases in plasma Ca concentration associated with the normal dietary Ca were substantial. In conclusion, the normal level of Ca in the diet greatly reduced the efficacy of supplemental phytase. Raising vitamin D in the diet partially offset this adverse effect but did not produce further improvement when the Ca level was low.

Supplementing corn-soybean meal diets with microbial phytase linearly improves phytate phosphorus utilization by weanling pigs

Two experiments were conducted with weanling pigs to determine the effectiveness of a dietary supplement of Aspergillus niger phytase in improving the availability of phytate-P in corn-soybean meal diets without supplemental inorganic P. Experiment 1 consisted of two P and Ca balance trials and two feeding trials. Twelve pigs (8.18 +/- .44 kg BW) were housed individually in stainless steel metabolism cages. Six pigs received 750 phytase units (PU)/g of basal diet and the other six pigs received the basal diet without supplemental phytase as control. In Exp. 2, 96 pigs (8.81 +/- .75 kg BW) were allotted to 16 partially slotted floor pens and their basal diets were supplemented with either 0, 250, 500, or 750 PU/g for 4 wk. Individual pig weights and pen feed consumption were measured weekly. Blood samples were taken from all pigs at the end of each trial in Exp. 1 and from three pigs per pen weekly in Exp. 2 to measure serum (plasma) inorganic P (P) and Ca concentrations and alkaline phosphatase (AP) activities. The results of Exp. 1 indicated that dietary phytase increased P retention by 50% (P < .0001) and decreased fecal P excretion by 42% (P < .0001). Pigs that received dietary phytase had serum P and Ca concentrations and serum AP activities that were nearly normal, whereas control pigs had values indicative of a moderate P deficiency. Favorable effects of phytase disappeared when the phytase was removed from the diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Supplementing corn-soybean meal diets with microbial phytase maximizes phytate phosphorus utilization by weanling pigs

Two experiments were conducted with crossbred weanling pigs to determine the optimal dietary supplement of Aspergillus niger phytase activity to a low-P, corn-soybean meal basal diet (BD). In Exp. 1, 50 pigs (7.61 +/- .56 kg BW) received the BD supplemented with 750, 1,050, 1,250, or 1,350 phytase units (PU)/g, or .21% P as mono-dibasic calcium phosphate (MDCaP) for 4 wk. In Exp. 2, 12 pigs (6.39 +/- .74 kg BW) were individually housed in metabolism cages and received BD, BD plus the optimal phytase activity (1,200 PU/g), or BD plus .21% P as MDCaP for 2 wk. In Exp. 1, additions of phytase > 1,050 PU/g of BD did not improve ADG, ADFI, gain/feed, or plasma AP activity. Quadratic relationships between dietary phytase activity and these measures were found and their stationary points were at approximately 1,200 PU/g of BD. Estimated maximum responses of these measures in pigs fed phytase were > or = 90% compared with MDCaP. Pigs fed 1,250 PU/g of BD maintained normal plasma P and Ca concentrations. In Exp. 2, pigs that received 1,200 PU/g of BD utilized dietary P more effectively (P < .05) than pigs fed the BD or the BD plus MDCaP. Although they consumed 44% less P per day, these pigs retained only 7% less P than pigs that received MDCaP. One thousand units of phytase activity supported retention of 1.1 mg of P from the BD, and this level of phytase supplementation was equivalent in effect to .91 mg of P from MDCaP.(ABSTRACT TRUNCATED AT 250 WORDS)

[3H]phytic acid (inositol hexaphosphate) is absorbed and distributed to various tissues in rats

To understand the mechanism of antineoplastic action of phytic acid, we investigated the absorption and distribution of myo-[inositol-2-3H(N)] hexakisphosphate in rats. The radioactivity was measured in urine, feces, blood, gastrointestinal tract contents and various organs and tissues at 1 and 24 h after intragastric administration. Of the total radioactivity, 79.0 +/- 10.0% was absorbed and at least 26.6% was degraded during the 24-h period following ingestion. The absorption was rapid; 11.0 +/- 2.6% of the radioactivity was detected in the wall of the stomach (4.4 +/- 3.7%) and upper small intestine (6.6 +/- 1.9%), 6.5 +/- 2.6% in the skeletal muscle and 4.0 +/- 1.5% in the skin after 1 h. Much of the radioactivity after 24 h was in the liver (4.0 +/- 0.9%), kidneys (2.2 +/- 1.1%), muscle (18.1 +/- 3.4%) and skin (10.1 +/- 3.3%). Analysis of plasma and urine demonstrated that most of the radioactivity was due to myo-inositol and small amounts of inositol monophosphate (InsP1). Gastric epithelial cells, however, contained inositol and various inositol phosphates (InsP1-6). Our data suggest that soluble InsP6 when administered in drinking water is rapidly absorbed through the stomach and upper small intestine, becomes quickly dephosphorylated within the mucosal cells and is distributed to various organs as inositol and InsP1.

Disappearance of phosphorus in phytate from concentrates in vitro and from rations fed to lactating dairy cows

Objectives were to determine concentrations of P in phytate in selected concentrates, disappearance of P in phytate from these concentrates in vitro, and extent of hydrolysis of phytate in vivo. Total P and P in phytate were determined for eight concentrates; 32 to 81% of total P was in phytate. Six concentrates were incubated in vitro to determine the extent of phytate disappearance from solids and its appearance and disappearance from solution. Greater than 90% of P in phytate disappeared from solids between 6 and 8 h of incubation in vitro (wheat middlings, rice bran, hominy, soybean meal, and dried distillers grains) or between 12 and 24 h (cottonseed meal). Phosphorus in phytate in solution was hydrolyzed by 12 h except for cottonseed meal (by 24 h). Hydrolysis of the inositol ring to release P in vivo was greater than 99%, based on total fecal collection from 11 cows and the use of Cr as an indigestible marker in excreta, and between 94 to 98% for the same samples when acid detergent lignin was used as an indigestible marker to calculate phytate disappearance. These results further indicate that P in phytate should be considered available to lactating dairy cows when rations to meet their P requirements are being formulated.