Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.8 (phytase)
 1,997 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of phytase and alkaline phosphatase in the intestine gradually increased in parallel during development of rats, but the 70K and 90K subunits were expressed differentially; only the 70K subunit was detected at birth, whereas the 90K subunit appeared at the weaning period (3 weeks after birth). When rats were forced to wean at 18 days old and fed laboratory chow, the enzyme activity increased markedly and the 90K subunit appeared within 1 day. These findings suggest that weaning is involved in the change in the subunit composition. Increases in the enzyme activity and amount of the 90K subunit were significantly delayed by feeding weanling animals on casein diet, but induced significantly by feeding them on casein diet supplemented with phytate. Thus induction of the 90K subunit seems to be accelerated by intake of phytic acid in the diet. The Km value of the enzyme from suckling rats for phytate was 5.25 mM, while that of adult rats was 0.213 mM. In contrast, the Km value for p-nitrophenyl phosphate (PNPP) was constant during development. The phytase activity of suckling rats did not show a distinct pH-dependence. These findings suggest that the 90K subunit may play some important roles in expressing an efficient phytase activity.
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PMID:Developmental and dietary induction of the 90K subunit of rat intestinal phytase. 165 11

An Fe depletion-repletion chick bioassay was conducted to determine whether supplemental microbial phytase or 1 alpha-hydroxycholecalciferol (1 alpha-OH D3) would improve the bioavailability of Fe in soybean meal (SBM). Weight gain, hemoglobin, and hematocrit were markedly improved when increasing levels (0, 10, 20, and 80 mg/kg) of Fe from analytical grade ferrous sulfate (FeSO4.7H2O) were added to the Fe-deficient casein-dextrose basal diet containing 20 mg Fe/kg. Addition of 19 mg Fe/kg from SBM to the basal diet improved (P < 0.05) hemoglobin and hematocrit, but the response was less than that obtained from 10 mg Fe/kg from FeSO4.7H2O. Phytase (1,430 units/kg), 1 alpha-OHD3 (10 micrograms/kg), or the combination, added to the SBM-fortified basal diet did not further improve hematocrit or hemoglobin, indicating that Fe bioavailability of SBM was not increased by either of these feed additives. Based on standard-curve methodology, and using hemoglobin as a criterion, the relative bioavailability of Fe was 38.5% for SBM, 21.0% for SBM+phytase, 23.2% for SBM+1 alpha-OHD3, and 29.2% for SBM+phytase+ 1 alpha-OHD3.
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PMID:Iron bioavailability in soybean meal as affected by supplemental phytase and 1 alpha-hydroxycholecalciferol. 931 19

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.
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PMID:Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3. 937 14

Four experiments were conducted to examine the effects of a microbial phytase (Natuphos), individually and in combination with glycanase preparations with predominantly xylanase (Natugrain Blend) and glucanase (Natugrain) activities, on the nutritive value of wheat and barley. In Experiment 1, the addition of xylanase and phytase increased the AME of a low-AME wheat by 9.7 and 5.3%, respectively. The differences, however, were not significant (P > 0.05). The combination of the two enzymes increased (P < 0.05) the AME of wheat by 19.0% from 2,646 to 3,149 kcal/kg dry matter. A similar trend was seen in terms of ileal amino acid digestibility values of the wheat-casein diet. In Experiment 2, the AME of normal wheat was increased (P < 0.05) by 6.3 and 4.5%, respectively, with the addition of xylanase and phytase. The combination of the two enzymes, however, did not further improve (P > 0.05) the AME values. In Experiment 3, performance of broilers fed a wheat-based diet was not influenced by the addition of individual enzymes, but increasing inclusion levels of the xylanase plus phytase combination linearly improved weight gain (r = 0.58; P < 0.01) and feed efficiency (r = 0.71; P < 0.001). In Experiment 4, the AME of barley was not influenced by the addition of glucanase or phytase. The enzyme combination marginally (P < 0.07) improved the AME at lower concentrations, but had no benefit at the highest concentration.
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PMID:Effects of phytase supplementation, individually and in combination, with glycanase, on the nutritive value of wheat and barley. 1056 Aug 33

Rice bran protein isolate (RBPI) containing approximately 92.0% protein was prepared from unstabilized and defatted rice bran using phytase and xylanase. The yield of RBPI increased from 34% to 74.6% through the use of the enzymatic treatment. Nitrogen solubilities of RBPI were 53, 8, 62, 78, 82, and 80% at pHs 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0, respectively. Differential scanning calorimetry showed that RBPI had denaturation temperature of 83.4 degrees C with low endotherm (0.96 J/g of protein). RBPI had similar foaming properties in comparison to egg white. But emulsifying properties of RBPI were significantly lower than those of bovine serum albumin. The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.
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PMID:Preparation and functional properties of rice bran protein isolate. 1056 9

Five groups of individually housed albino rats (n = 7 each, initial average weight = 42 g) were fed diets based on corn starch and casein over a 4-week period. All diets were supplemented with 35 mg/kg of iron from FeSO4 x 7 H2O. Group I (control) was fed the basal diet free of phytic acid (PA) and phytase. By replacing corn starch by 7.5 g (groups II and IV) and 15 g phytic acid (groups III and V) from sodium phytate per kg diet, molar PA/iron ratios of 18 and 36 were obtained. In groups IV and V, 1000 U phytase from Aspergillus niger per kg diet were added. Food conversion efficiency ratio and growth rate as well as iron in plasma and spleen, hemoglobin, red blood cell count and erythrocyte zinc protoporphyrin were not influenced by the different dietary treatments. Dietary phytate reduced apparent iron absorption in groups II and III. Furthermore hematocrit, transferrin saturation and iron concentration in liver and femur were lowered in rats fed diets with PA, while total and latent iron-binding capacity of plasma increased. Microbial phytase supplementation (groups IV and V) partly counteracted the antinutritive effects of phytic acid on iron availability.
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PMID:Supplemental sodium phytate and microbial phytase influence iron availability in growing rats. 1061 76

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.
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PMID:The effects of citric acid on phytate-phosphorus utilization in young chicks and pigs. 1076 76

Marginal zinc deficiency and suboptimal zinc status have been recognized in many groups of the population in both less developed and industrialized countries. Although the cause in some cases may be inadequate dietary intake of zinc, inhibitors of zinc absorption are most likely the most common causative factor. Phytate, which is present in staple foods like cereals, corn and rice, has a strong negative effect on zinc absorption from composite meals. Inositol hexaphosphates and pentaphosphates are the phytate forms that exert these negative effects, whereas the lower phosphates have no or little effect on zinc absorption. The removal or reduction of phytate by enzyme (phytase) treatment, precipitation methods, germination, fermentation or plant breeding/genetic engineering markedly improves zinc absorption. Iron can have a negative effect on zinc absorption, if given together in a supplement, whereas no effect is observed when the same amounts are present in a meal as fortificants. Cadmium, which is increasing in the environment, also inhibits zinc absorption. The amount of protein in a meal has a positive effect on zinc absorption, but individual proteins may act differently; e.g., casein has a modest inhibitory effect of zinc absorption compared with other protein sources. Amino acids, such as histidine and methionine, and other low-molecular-weight ions, such as EDTA and organic acids (e.g., citrate), are known to have a positive effect on zinc absorption and have been used for zinc supplements. Knowledge about dietary factors that inhibit zinc absorption and about ways to overcome or remove these factors is essential when designing strategies to improve the zinc nutrition of vulnerable groups.
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PMID:Dietary factors influencing zinc absorption. 1080 47

An amino acid deletion assay, a protein efficiency ratio (PER) assay, and a slope-ratio growth assay were used to establish the limiting order of AA, and to determine the effects of microbial phytase on protein utilization in corn gluten meal (CGM) fed to chicks during the period of 8 to 21 d posthatching. In Assay 1, a 12% CP CGM diet was fortified with AA to fulfill the digestible AA ideal profile (only Phe + Tyr, Leu, and Pro exceeded requirements) for young chicks. Amino acids were then individually deleted, and all diets were fortified to 23% CP, with Glu varying as necessary. A Met-fortified 23% CP corn-soybean meal diet served as a positive control. No weight gain or feed efficiency differences were observed between the fully fortified CGM basal diet and the corn-soybean meal positive-control diet. The limiting order of AA established in CGM was 1) Lys, 2) Trp, 3) Arg, 4) Thr, 5) Val, 6) Ile, 7) His, 8) cystine, and 9) Met. In Assay 2, diets with 10% CP furnished by CGM or casein were fed in the presence and absence of 1,200 U/kg phytase. A protein source x phytase interaction (P < 0.05) was observed for weight gain, gain:feed, and PER, indicating positive responses to phytase when casein was fed but negative responses to phytase when CGM was fed. In Assay 3, graded levels of protein (8, 16, and 24% CP) furnished by CGM were fed in the presence and absence of 1,200 U/kg phytase. Weight gain and gain:feed increased linearly (P < 0.05) as a function of protein intake, but phytase supplementation had no effect on weight gain or gain:feed slopes. These results indicate that 1,200 U/kg phytase did not increase either CP or AA utilization in CGM for young chicks.
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PMID:Limiting order of amino acids and the effects of phytase on protein quality in corn gluten meal fed to young chicks. 1094 2

Three growth trials were conducted with young chicks to evaluate crude protein (CP) utilization in soybean meal (SBM) as affected by dietary addition of microbial phytase. In assay 1, chicks were fed two CP-deficient (50 or 150 g CP/kg) levels of dehulled SBM, and each SBM level was then supplemented with equimolar amounts of cystine or methionine (Met) or with 1200 U phytase/kg. At 50 g CP/kg, cystine or Met supplementation improved (P < 0.05) measures of growth performance, but when 150 g CP/kg from SBM was fed, only Met addition improved (P < 0.05) weight gain, food efficiency and protein efficiency ratio (PER). Thus, Cys was more limiting than Met in the diet that contained 50 g CP/kg, but Met was clearly first-limiting in the diet that contained 150 g CP/kg. Phytase supplementation did not improve (P > 0.10) chick performance at either level of CP. Chicks in assay 2 were fed 100 g CP/kg furnished by SBM, casein or corn gluten meal in the absence and presence of 1200 U phytase/kg. Weight gain, gain/food and PER values were greater (P < 0.05) in chicks fed SBM than in those fed casein, and greater (P < 0.05) in chicks fed casein than in those fed corn gluten meal. Phytase supplementation had no effect (P > 0.10) on any measure of chick performance, regardless of the protein source fed. In assay 3, three deficient levels of CP (50, 100 and 150 g/kg) from SBM were fed in the absence and presence of 1200 U dietary phytase/kg. Weight gain, food efficiency and protein accretion increased linearly (P < 0.05) as a function of protein intake, but phytase supplementation had no effect (P > 0.10) on slopes of the body weight and protein accretion curves. Likewise, phytase addition did not affect (P > 0.10) measures of protein utilization, i.e., weight gain/protein intake and protein gain/protein intake at any of the CP levels that were fed. Because sulfur amino acids are the growth-limiting factors when protein-deficient levels of SBM are fed to young chicks, we conclude that dietary addition of phytase does not improve sulfur amino acid utilization in SBM.
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PMID:Microbial phytase does not improve protein-amino acid utilization in soybean meal fed to young chickens. 1138 69


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