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)

1. The study aimed to assess the effect of a commercially available microbial phytase on phytate phosphorus and total phosphorus content at the terminal ileum as well as true ileal amino acid digestibility. 2. Five diets, each containing a different plant-based feedstuff, were supplemented with microbial phytase and fed, along with a non-supplemented corresponding diet, to 28-d-old broiler chickens, Chromic oxide was used as an indigestible marker. Ileal contents were collected and analysed, along with the diets, for total phosphorus, phytate phosphorus and amino acids. 3. Endogenous phosphorus determined at the terminal ileum was 272 +/- 108 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acid flows ranged from 58 +/- 10 mg/kg food dry matter for methionine to 568 +/- 47 mg/kg food dry matter for glutamic acid. 4. Supplementation with microbial phytase resulted in a significantly greater phytate P disappearance from the terminal ileum for rice bran (17% units), but not for soyabean meal, maize, wheat or rapeseed meal. Similarly total phosphorus digestibility was significantly (P < 0.05) higher when microbial phytase was added to the rice-bran-based diet but not for any of the other feedstuffs. 5. Amino acid digestibility was significantly greater in the presence of microbial phytase for all the amino acids examined in wheat, for several of the amino acids each in maize and rapeseed meal and for one amino acid in rice bran and soyabean meal. The average increase in amino acid digestibility for those amino acids affected, was 13, 6, 10, 7 and 12% units for wheat, maize, rapeseed meal, rice bran and soyabean meal, respectively. 6. It appears that microbial phytase improves phosphorus digestibility and amino acid digestibility for certain plant-based feedstuffs.
Br Poult Sci 2002 Sep
PMID:The effect of microbial phytase on ileal phosphorus and amino acid digestibility in the broiler chicken. 1236 17

1. Large White male turkeys from a heavy commercial male-line were fed on 16 diets containing 4 concentrations of calcium (6, 10, 14 and 18 g/kg) and available phosphorus (3, 5, 7, 9 g/kg) in a 4 x 4 factorial experiment with three replicates (pens). Turkeys were weighed and food intakes recorded from 4 to 7, 8 to 10 and 11 to 13 weeks of age. 2. The diets containing 6 g/kg calcium and 5, 7 or 9 g/kg available phosphorus concentrations were associated with lower body weighs at 10 and 13 weeks of age. 3. Fewer than 6% of the turkeys had an abnormal gait at 13 weeks of age. 4. The optimum dietary concentrations were 10 g/kg of calcium and 3 g/kg of available phosphorus. It was concluded that these concentrations should be fed at least to 13 weeks of age. 5. Retentions of dietary calcium and phosphorus averaged 300 g/kg of intake. 6. Utilisation of dietary phytate ranged from 5 to 11 g/kg and it is recommended that organic phosphorus should be ignored in the formulation of diets for growing turkeys unless they are supplemented with a phytase enzyme.
Br Poult Sci 2002 Sep
PMID:Effects of dietary calcium and phosphorus on mineral retention, growth, feed efficiency and walking ability in growing turkeys. 1236 18

Regulation of hydration behavior, and the concomitant effects on solubility and other properties, has been suggested as a main function of protein glycosylation. In this work, we have studied the hydration of the heavily glycosylated Peniophora lycii phytase in solutions (0.15-1.1 m) of the two compatible solutes glycerol and sorbitol. Osmometric measurements showed that glycerol preferentially binds to phytase (i.e., glycerol-glycoprotein interactions are more favorable than water-glycoprotein interactions resulting in a preferential accumulation of glycerol near the protein interface), while sorbitol is preferentially excluded from the hydration sphere (water-glycoprotein interactions are the more favorable). To assess contributions from carbohydrate and peptide moieties, respectively, we compared phytase (Phy) and a modified, yet enzymatically active form (dgPhy) in which 90% of the glycans had been removed. This revealed that both polyols showed a pronounced and approximately equal degree of preferential binding to the carbohydrate moiety. This preferential binding of polyols to glycans is in contrast to the exclusion from peptide interfaces observed here (for dgPhy) and in numerous previous reports on nonglycosylated proteins. Despite the distinct differences between peptide and carbohydrate groups, glycosylation had no effect on the stabilizing action provided by glycerol and sorbitol. On the basis of this, it was concluded that the carbohydrate mantle of Phy is equally accessible in the native and thermally denatured states, respectively (most likely fully accessible in both), and thus that its interactions with compatible solutes have little or no effect on conformational equilibria of the glycoprotein. For solubility and aggregation equilibria, on the other hand, the results suggest a polyol-induced stabilization of monomeric forms.
Biochemistry 2003 Sep 02
PMID:Preferential binding of two compatible solutes to the glycan moieties of Peniophora lycii phytase. 1293 59

Two experiments were conducted to determine whether the presence of 25-OH-cholecalciferol (25-OH-D3) as compared to vitamin D3 produces any beneficial effect on shell quality of laying hens. Experiment 1 consisted of a 4 x 2 factorial arrangement of the treatments with four determined Ca levels (3.34, 4.3, 4.73, and 4.94%) and two sources of vitamin D (vitamin D3 and 25-OH-D3, which were used at 69 microg/kg diet or 2,760 IU/kg diet). Experiment 2 consisted of a 3 x 2 x 2 factorial arrangement of the treatments with three determined levels of nonphytate P (NPP) (0.11, 0.21, and 0.41%), two levels of phytase (0 and 300 U/kg diet), and two sources of vitamin D (vitamin D3 and 25-OH-D3, which were used at 69 microg/kg diet, the equivalent of 2,760 IU/kg diet). Substitution of vitamin D3 with 25-OH-D3 in neither of the experiments produced any beneficial effect on shell quality. A Ca level of 3.34%, which provided the birds with 3.63 g Ca/hen per d, was adequate for performance and eggshell quality. The NPP level of 0.11% was not sufficient to support performance. However, a NPP level of 0.21% was adequate and resulted in performance that was comparable to that of birds fed the 0.41% NPP diet. The presence of phytase did not have an effect on performance but reduced several indices of the shell quality. In conclusion, under the conditions of the current experiments, the use of 25-OH-D3 did not provide any advantage for shell quality or production performance.
Poult Sci 2003 Sep
PMID:A comparison between cholecalciferol and 25-OH-cholecalciferol on performance and eggshell quality of hens fed different levels of calcium and phosphorus. 1296 55

An experiment was conducted to determine the minimum levels of nonphytate P (NPP) with and without phytase that can be continuously and safely used during the growing and laying periods for diminishing P excretion to the environment. The experiment consisted of a 2 x 8 factorial arrangement of the treatments with two strains (Babcock B-300 and Hy-Line W-98) and eight diets. The birds of the control group (T1) were fed a determined NPP regimen of 0.34-0.30-0.23% for the periods of 0 to 6 wk (0.34%), 6 to 12 wk (0.30%), and 12 to 18 wk (0.23%) of age and 0.39% determined NPP during the laying period (18 to 26 wk of age). The dietary NPP regimens during the growing and laying periods for T2 to T5 were as follows: T2, 0.25-0.20-0.16 and 0.29%; T3, 0.15-0.10-0.08 and 0.18%; T4, 0.12-0.07-0.08 and 0.12%; and T5, 0.08-0.07-0.08, and 0.08%. The birds of T6 to T8 were fed diets similar to T3 to T3 plus 300 U phytase/kg of diet. The growth parameters and egg production performance of birds of T2, which were fed the NPP regimen of 0.25-0.20-0.16% during the growing period and 0.29% NPP during the laying period, and those of T6, which were fed a NPP regimen of 0.15-0.10-0.08% plus phytase during the growing period and 0.18% NPP plus phytase during the laying period were similar to the control group. However, their total P intakes were 16.1 and 44% lower, respectively, and their NPP intakes were 29.7 and 64.1% lower, respectively, than the control group during the entire growing period. During the digestion trial (wk 16), daily total P excretion of these two groups (T2 and T6) were 21.2 and 43.1%, respectively, lower than the control groups. The birds fed T3, T4, and T5 regimens had consistently inferior performance than the controls both during the growing and laying periods. Phytase completely alleviated the adverse effect of the low-NPP levels fed to T3 during the growing and laying periods and partially alleviated the adverse effects of low-NPP regimens fed to birds of T4 and T5 during the growing and laying periods. Additional experiments involving longer laying cycles are warranted prior to making practical recommendations.
Poult Sci 2003 Sep
PMID:Effects of continuous feeding of low-phosphorus diets with and without phytase during the growing and laying periods on performance of two strains of Leghorns. 1296 59

In an effort to produce phytases cost-effectively, and to determine the efficiency of a novel expression system, the genes for Aspergillus awamori ( phyA) phytase and Aspergillus fumigatus ( phyA) phytase (a putative thermostable enzyme) were cloned and overexpressed in A. awamori. Regulation of phytase expression was achieved by separately placing the genes under the transcriptional control of the glucoamylase A ( glaA) promoter of A. awamori. A gene fusion strategy was employed that involved the insertion of a hexapeptide Kex-2 protease cleavage site between the native glucoamylase and heterologous proteins and allowed for the efficient secretion and processing of the resultant chimeric proteins produced in this system by an endogenous Kex-2 protease. The genes for both of the above-mentioned phytases have already been cloned; however, this is the first report of either of the two phytases being fused with the glucoamylase gene, placed under the transcriptional control of the glaA promoter and overexpressed in A. awamori. Following transformation of A. awamori with separate expression vectors (one for each phytase), induction of phytase expression in submerged culture was effected by utilisation of a starch-containing medium. Optimisation of heterologous protein production in small shake-flask cultures involved changes in medium constituents. Maximum phytase expression levels of 200 phytase units (PU) ml(-1) and 62 PU ml(-1) for recombinantly expressed phytases from A. awamori and A. fumigatus, respectively, were obtained in crude fermentation extracts. Subsequent process scale-up to 4 l batch fermentation yielded phytase production levels comparable to those obtained on small scale. The enzyme yields herein reported demonstrate that the expression system developed and the host strain utilised were capable of expressing phytase at levels comparable to, or exceeding, previously reported data.
J Ind Microbiol Biotechnol 2003 Sep
PMID:Cloning and expression of fungal phytases in genetically modified strains of Aspergillus awamori. 1451 84

1. An experiment lasting for 13 weeks was started at the beginning of week 10 with male turkeys weighing 5.38 kg. The experiment comprised three subsequent periods with adjusted metabolisable energy (ME) and nutrient concentrations from weeks 10 to 13, 14 to 17, and 18 to 22. Seven pens of 12 birds each were allocated to each of 5 treatments. Treatments differed in dietary phosphorus concentration and phytase supplementation (500 U/kg) only. Total phosphorus varied between treatments from 4.9 to 8.0 g/kg (weeks 10 to 13), from 4.4 to 7.5 g/kg (weeks 14 to 17) and from 3.5 to 7.0 g/kg (weeks 18 to 22). Phosphorus concentration was adjusted by different inclusions of monocalcium phosphate. Diets were pelleted and offered ad libitum. 2. A final body weight of, on average, 22.3 kg was achieved at the end of week 22. Body weight gain, feed consumption, feed conversion, toe ash, toe phosphorus and toe calcium were not significantly affected by dietary phosphorus concentration. There was no indication of an effect on mortality or on broken or deformed bones. 3. Phosphorus concentrations (g/kg diet) of 5.9, 5.4 and 4.4 without microbial phytase and of 4.9, 4.4 and 3.5 with microbial phytase, respectively, were sufficient in the three periods. As compared with the control, a reduction in phosphorus excretion of turkeys by 0.4 without phytase and by 0.5 with phytase was achieved without negative effects on turkeys. 4. Because the data demonstrate the great potential for a reduction in dietary phosphorus concentration, detailed requirement and availability studies with turkeys should follow.
Br Poult Sci 2003 Sep
PMID:Reducing the phosphorus concentration in diets for turkeys between 10 and 22 weeks of age. 1458 49

Understanding of the atomic movements involved in an enzymatic reaction needs structural information on the active and inactive native enzyme molecules and on the enzyme-substrate, enzyme-intermediate, and enzyme-product(s) complexes. By using the X-ray crystallographic method, four crystal structures of Aspergillus fumigatus phytase were obtained at resolution higher than 1.7 A. The pH-dependent catalytic activity of A. fumigatus phytase was linked to three water molecules that may prevent the substrate from binding and thus block nucleophilic attack of the catalytic imidazole nitrogen. Comparison of various structures also identified the water molecule that attacks the phosphamide bond during the hydrolysis process, and established the hydrolysis pathway of the intermediate. Additionally, two reaction product phosphates were observed at the active site, suggesting a possible product release pathway after hydrolysis of the intermediate. These results can help explain the catalytic mechanism throughout the whole acid phosphatase family, as all key residues are conserved.
Structure 2004 Sep
PMID:Crystallographic snapshots of Aspergillus fumigatus phytase, revealing its enzymatic dynamics. 1534 23

An experiment was conducted to determine the effects of phytase addition, reduced Ca and available P (aP), and removing the trace mineral premix (TMP) on growth performance, plasma metabolites, carcass traits, pork quality, and tissue mineral content in growing-finishing swine. One hundred twenty cross-bred pigs (initial and final BW of 22 and 109 kg, respectively) were allotted to five dietary treatments on the basis of weight within gender in a randomized complete block design. There were three replications of barrows and three replications of gilts, with four pigs per replicate pen. The dietary treatments were as follows: 1) corn-soybean meal (C-SBM), 2) C-SBM with reduced Ca and aP, 3) C-SBM with reduced Ca and aP plus 500 phytase units/kg of diet, 4) Diet 1 without the TMP, and 5) Diet 3 without the TMP. The Ca and aP were reduced by 0.10% in the low Ca and aP diets and the diets with added phytase. Daily gain, hot carcass weight, dressing percent, kilograms of carcass lean, bone ash percent, and bone strength were decreased (P = 0.10), but liver and kidney weight were increased (P = 0.10) in pigs fed diets with reduced Ca and aP; adding phytase reversed these responses (P = 0.10). The Commission Internationale de I'Eclairage L* was decreased (P = 0.09) in pigs fed the low Ca and aP diet plus phytase relative to those fed the control diet. Removing the TMP had no effect on overall growth performance, but it increased (P = 0.03) 10th-rib backfat thickness and fasting glucose and decreased (P = 0.03) carcass length and ham weight. Liver weight and liver weight as a percentage of final BW were not affected when phytase was added to the control diet, but removing the TMP increased liver weight and liver weight as a percentage of final BW; adding phytase reversed these responses (phytase x TMP, P = 0.06). Removing the TMP decreased (P = 0.08) Zn concentrations in the bone, muscle, and liver, and Cu and Fe concentrations in the bile but increased (P = 0.08) Mn concentrations in the bile and liver of pigs. The addition of phytase reversed the negative effects of the reduced Ca and aP diets. These data indicate that removing the TMP in diets for growing-finishing pigs has no negative effects on growth performance or pork quality, but it had negative effects on carcass traits and had variable effects on tissue mineral content.
J Anim Sci 2004 Sep
PMID:Effects of microbial phytase, low calcium and phosphorus, and removing the dietary trace mineral premix on carcass traits, pork quality, plasma metabolites, and tissue mineral content in growing-finishing pigs. 1544 80

Five experiments were conducted to evaluate the effect of an Escherichia coli-derived phytase on phytate-P use and growth performance by young pigs. The first experiment involved time course, pH dependence, and phytase activity studies to investigate the in vitro release of P from corn, soybean meal, and an inorganic P-unsupplemented corn-soybean meal negative control diet. In Exp. 2, which was designed to determine the efficacy of the E. coli-derived vs. fungal phytase-added diets at 0, 250, 500, 750, 1,000, or 1,250 FTU/kg (as-fed basis; one phytase unit or FTU is defined as the quantity of enzyme required to liberate 1 micromol of inorganic P/min, at pH 5.5, from an excess of 15 microM sodium phytate at 37 approximately C) and a positive control diet, eight individually penned 10-kg pigs per diet (12 diets, 96 pigs) were used in a 28-d growth study. The third experiment was a 10-d nutrient balance study involving six 13-kg pigs per diet (four diets, 24 pigs) in individual metabolism crates. In Exp. 4, eight pens (four pigs per pen) of 19-kg pigs per treatment were used in a 42-d growth performance study to examine the effect of adding the E. coli-derived phytase to corn-soybean diets at 0, 500, or 1,000 FTU/kg (as-fed basis) and a positive control (four diets, 128 pigs). In Exp. 5, six 19-kg pigs per treatment were used in a 10-d nutrient balance study to investigate the effects of the E. coli-derived phytase added to diets at 0, 250, 500, 750, or 1,000 FTU/kg (as-fed basis) and a positive control diet (six diets, 36 pigs). The in vitro study showed that the E. coli-derived phytase has an optimal activity and pH range of 2 to 4.5. Inorganic phosphate release was greatest for soybean meal, least for corn, and intermediate for the negative control diet. Dietary supplementation with graded amounts of E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain, feed efficiency, and plasma Ca and P concentrations in 10-kg pigs in Exp. 2. Phytase also increased P digestibility and retention in the 13-kg pigs in Exp. 3. In Exp. 4, dietary supplementation with E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain and feed efficiency of 19-kg pigs. Supplementation of the diets of 19-kg pigs with the E. coli-derived phytase also improved Ca and P digestibility and retention in Exp. 5. In the current study, the new E. coli-derived phytase was efficacious in hydrolyzing phytate-P, both in vitro and in vivo, in young pigs.
J Anim Sci 2004 Sep
PMID:The efficacy of an Escherichia coli-derived phytase preparation. 1544 83


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