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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)

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

This study was conducted to compare the efficacy of genetically engineered microbial (Natuphos) and plant (Phytaseed) phytase for enhancing the utilization of phytate P in corn-soybean meal-based diets fed to young broilers and to evaluate the safety of Phytaseed phytase. Three levels of each of the two sources of phytase (250, 500, and 2,500 U/kg of diet) were added to a corn-soybean meal basal diet containing 0.46% total P, 0.21% nonphytate P, and 0.92% Ca. There were eight cages per treatment (eight birds per cage for Weeks 2 to 3 and seven birds for Weeks 4 to 5), except for the basal diet without added phytase that had 16 cages. Cage BW and feed consumption were recorded weekly. During Week 5, cage excreta samples were collected for determination of apparent retention coefficients of DM, Ca, and P. At the end of Week 5, all birds were killed, and the left and right toes were removed for determination of toe ash weight and percentage. Forty birds (one per cage from the diet without added phytase and diets with 500 or 2,500 U phytase/kg from both sources) were randomly selected for gross necropsy and histologic evaluation of liver, kidney, and bone tissues. Addition of both sources of phytase resulted in similar increases (P < 0.05) of BW gain; feed intake; gain:feed; apparent retention of DM, P and Ca; and toe measurements. Phosphorus excretion decreased as phytase addition increased. No significant abnormalities were seen in any of the 40 broilers necropsied. Further, the fit of a nonlinear function revealed that most measurements reached a plateau at 2,500 U/kg. Based on performance, bone characteristics, and retention of P, Ca, and DM of young broilers, the efficacy of Phytaseed phytase was similar to that of Natuphos phytase for enhancing the utilization of phytate P in corn-soybean meal-based diets. General necropsy and histologic examination of liver, kidney, and tibial tissues revealed no adverse effects of phytase source or level.
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PMID:Comparison of genetically engineered microbial and plant phytase for young broilers. 1082 60

1. Male broilers (n=900) were fed on wheat-sorghum-soyabean meal based diets containing 3 concentrations of phytic acid (10.4, 13.2 and 15.7 g/kg; equivalent to 2.9, 3.7 and 4.4 g/kg phytate P), 2 concentrations of non-phytate (or available) phosphorus (2.3 and 4.5 g/kg) and 3 concentrations of microbial phytase (0, 400 and 800 FTU/kg) from day 7 to 25 post-hatch. The dietary concentrations of phytic acid were manipulated by the inclusion of rice pollards. All diets contained celite (20 g/kg) as a source of acid-insoluble ash. 2. The apparent metabolisable energy (AME) concentrations of the diets were determined using a classical total collection procedure during the 3rd week of the trial. On d 25, digesta from the terminal ileum were collected and analysed for phosphorus, nitrogen and amino acids. Nutrient digestibilities were calculated using acid-insoluble ash as the indigestible marker. 2. Ileal digestibilities of nitrogen and essential amino acids were negatively influenced by increasing dietary levels of phytic acid but these negative effects were overcome by the addition of phytase. 3. Supplemental phytase increased AME, ileal digestibilities of phosphorus, nitrogen and amino acids and the retention of dry matter, phosphorus and nitrogen in broilers. There were no differences in the phytase responses between additions of 400 and 800 FTU/kg. 4. The responses in all variables, except AME, were greater in low non-phytate phosphorus diets. 5. In the case of AME, the response to added phytase was greater in adequate non-phytate phosphorus diets. Supplemental phytase increased AME values from 13.36 to 13.54 MJ/kg dry matter in low non-phytate phosphorus diets and from 12.66 to 13.38 MJ/kg dry matter in adequate non-phytate phosphorus diets.
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PMID:Response of broiler chickens to microbial phytase supplementation as influenced by dietary phytic acid and non-phytate phosphorous levels. II. Effects on apparent metabolisable energy, nutrient digestibility and nutrient retention. 1089 Feb 16

An experiment was conducted to re-evaluate the nonphytate phosphorus (NPP) requirement of growing pullets and to determine to what extent this requirement could be reduced by phytase. Six diets in a 3 x 2 factorial design were used. The pullets of the control group (T1) were fed a sequence of 0.4-0.35-0.3% NPP for the age periods of 0 to 6, 6 to 12, and 12 to 18 wk, respectively, according to NRC (1994) recommendation. The NPP level was reduced by an increment of 0.1% in each phase in T2 and T3. The pullets of T4 to T6 were fed similar NPP levels to T1 to T3, respectively, with 300 units phytase/kg diet. From 18 to 30 wk of age, the pullets on all growing regimens were fed a layer diet with 0.4% NPP. Records were maintained for BW and feed intake during the growing period and for egg production during the laying period. Blood and tibia samples were taken at 6, 12, and 18 wk of age for determining plasma P, tibia weight, and tibia ash. Two digestion trials were conducted at Weeks 5 and 18 for determining total P excretion. Body weights at 18 wk and feed intake for the period of 0 to 18 wk were not different from the control for pullets fed the two lower NPP regimens (P > 0.05). Phytase had a favorable effect on BW at 18 wk (P = 0.0539) and feed intake for the period of 0 to 18 wk (P < 0.05). Plasma P was lower for pullets fed the least NPP than for those fed the control NPP regimen only at 6 wk of age (P < 0.05). Bone quality measurements at 6, 12, and 18 wk of age were not different for pullets fed various NPP regimens (P > 0.05). Phytase, for the most part did, not have an effect on plasma P and bone quality (P > 0.05). Total P intake and total P excretion (mg/bird per day) were reduced due to lowering the dietary NPP in both digestion trials (P < 0.05). Phytase did not have an effect on daily total P intake or excretion. Production and specific gravity were not influenced by NPP regimens used during the growing period. Specific gravity for the entire experiment was greater for pullets fed phytase (P < 0.05). The results indicated that the lowest NPP regimen in the absence of phytase was adequate to support performance of pullets, and due to this, it was not possible to determine the effect of phytase in diminishing the P need of growing pullets.
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PMID:Reevaluation of nonphytate phosphorus requirement of growing pullets with and without phytase. 1094 83

A study was conducted to determine the extent fecal P levels could be reduced while maintaining performance. Various strategies were employed including the use of a high available phosphorus hybrid of corn (HAPC), supplementation with phytase enzyme, and reduced dietary P levels. The use of HAPC resulted in a 50% reduction in phytate-bound dietary P as compared with a normal yellow dent corn (YDC) diet. Dietary nonphytate P was maintained at either NRC (1994) recommendations for appropriate age periods or reduced by 0.075 or 0.15%. Portions of the diets were supplemented with 1,000 units of phytase/kg. Male chicks of a commercial strain were grown to 56 d on the test diets. Broilers fed diets with HAPC had BW, feed conversion, livability, and tibia ash that were equal to or superior to those fed diets with YDC with considerably reduced fecal P content at any dietary level of nonphytate P. Phytase supplementation enabled birds to maintain live performance at lower levels of nonphytate P, further reducing the fecal P output. One of the greatest contributions of phytase was a reduction in mortality at the lower levels of nonphytate P. Dietary P levels could be reduced by 0.075% under NRC (1994) recommendations without adversely affecting live performance; a reduction of 0.15% in conjunction with phytase supplementation maintained BW, feed conversion, and livability but reduced tibia ash. The extent to which dietary P levels can be reduced over the entire feeding program is subject to further research.
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PMID:Evaluation of normal yellow dent corn and high available phosphorus corn in combination with reduced dietary phosphorus and phytase supplementation for broilers grown to market weights in litter pens. 1102 73

Efficacies of phytase, phosphorolytic enzymes (phytase + acid phosphatase), an enzymic "cocktail" (phytase + acid phosphatase + pectinase + citric acid), a novel Aspergillus niger (fungal) mycelium (FM), and FM enriched in phytase and antioxidants were investigated in growing broilers (Days 1 to 21) fed wheat-based diets. Broilers were fed the following seven diets at 0.69% Ca: 1) a negative control diet, 0.17% nonphytate P (NPP); 2) Diet 1 + 750 phytase units/kg diet; 3) Diet 1 + 750 phytase units + 3,156 units acid phosphatase/kg diet; 4) Diet 1 + 750 phytase units + 3,156 acid phosphatase units + 1,900 units of pectinase/g diet + 3% citric acid; 5) Diet 1 + 4% FM; 6) Diet 1 + 4% FM + 1,300 phytase units + 2% ascorbic acid and 1% of glucose oxidase; and 7) a positive control diet (Diet 1 + 0.24% NPP from dicalcium phosphate). The dietary treatments were fed to four pen replicates of eight birds each. Prior to feed formulation, mycelium and antioxidants dosages were optimized on Diet 1 by an in vitro technique and an experimental design module of a statistical software package. Phytase addition increased BW gain (BWG), feed intake, and P retention. Subsequent addition of acid phosphatase resulted in further increases in BWG, feed intake, and toe ash and reduced digesta viscosity; however, neither P nor Ca retention were improved. Body weight gain and feed intakes superior to those found in chicks fed Diet 7 were observed in birds receiving the cocktail of enzymes (Diet 4) or FM. Chicken fed Diet 6 had the highest percentage of toe ash and retained 76 and 51% of P and Ca, respectively. Supplementation of wheat-based 0.17% NPP diets with FM increased bursa of Fabricius weights and reduced the intestinal surface covered by Peyer's patches.
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PMID:Comparison of the efficacies of a novel aspergillus niger mycelium with separate and combined effectiveness of phytase, acid phosphatase, and pectinase in dephosphorylation of wheat-based feeds fed to growing broilers. 1105 50

A study was conducted to evaluate the ability of the young (0 to 3 wk) broiler chicken to utilize the P provided by a high available P corn [HAPC; 0.27% total P and 0.17% nonphytate P] in comparison with yellow dent corn (YDC; 0.23% total P and 0.03% nonphytate P), and to determine the extent to which supplementation with exogenous phytase enzyme could reduce the demands for dietary P and subsequently reduce P excretion. Diets prepared using the two types of corn differed in the amount of phytate-bound P, with the HAPC diets containing approximately 50% less phytate-bound P. Treatment diets were prepared by varying the amount of dicalcium phosphate, and ranged from 0.10 to 0.50% nonphytate P for YDC diets, and from 0.18 to 0.50% nonphytate P for HAPC diets. Sublots of each diet were supplemented with 800 units/kg phytase. Each diet was fed to six pens of five male chicks of a commercial broiler strain from 1 to 21 d of age. Regression analysis was used to estimate nonphytate P requirements for each corn type with and without phytase supplementation. The greatest need for nonphytate P was for maximum tibia ash, with requirements of 0.39, 0.29, 0.37, and 0.32% in diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Addition of phytase liberated approximately 50% of the phytate-bound P from each diet. These levels were sufficient to support body weight, feed conversion, and livability. Fecal P content of broilers fed diets with YDC at the NRC (1994) recommended level of 0.45% nonphytate P was 1.21%, whereas at the respective requirement points indicated above, the P content was 1.09, 0.87, 0.78, and 0.64% in feces from broilers fed diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Thus, fecal P output could be reduced while maintaining optimum performance by the use of reduced dietary nonphytate P, introduction of HAPC, and phytase supplementation. One of the greatest benefits of phytase supplementation appeared to be maintaining livability at lower dietary levels of nonphytate P.
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PMID:Nonphytate phosphorus requirement and phosphorus excretion of broiler chicks fed diets composed of normal or high available phosphate corn with and without microbial phytase. 1105 52

An 18-d experiment was conducted to determine the effect of varying mix uniformity of phytase on growth performance, mineral retention, and bone mineralization in chicks. Chicks (initial and final weights were 74.5 and 803.3 g) were allotted to seven treatments with six (Treatment 1) or seven (Treatments 2 to 7) replicates of seven chicks per replicate in a completely randomized design. Varying mix uniformity of phytase was simulated by alternately providing two diets with two different concentrations of microbial phytase; the diets were switched every 24 h. Treatments were: 1) positive control (CON) (Ca, 1.0%; available phosphorus (aP), 0.45%), 2) negative control (NEG) (Ca, 0.9%; aP, 0.35%), 3) NEG + 600 phytase units (FTU) daily (CV0), 4) NEG + 500 or 700 FTU (CV17), 5) NEG + 400 or 800 FTU (CV34), 6) NEG + 200 or 1,000 FTU (CV69), or 7) NEG + 0 or 1,200 FTU (CV103). Gain, feed intake, and bone breaking strength were similar (P > 0.15) in the CON and CV0 treatments, but these response variables were decreased in the NEG treatment (P < 0.01). Gain:feed was not affected by treatment (P = 0.15). Bone ash was decreased (P < 0.02) by the NEG and CV0 treatments compared with the CON diet, but chicks fed the CV0 diet had greater bone ash than those fed the NEG (P < 0.01) diet. Increasing FTU CV decreased bone breaking strength and bone ash (P < 0.01). Calcium and phosphorus retention (P < 0.08) and gain (P < 0.09) were numerically decreased, and phosphorus excretion was numerically increased (P < 0.07) as FTU CV increased. The difference between the CV0 and CV103 treatments was significant only for bone breaking strength and ash (P < 0.01). In conclusion, increasing phytase CV had little effect on growth performance, whereas bone ash and breaking strength and calcium and phosphorus retention and excretion decreased only at the most extreme CV.
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PMID:The effect of varying mix uniformity (simulated) of phytase on growth performance, mineral retention, and bone mineralization in chicks. 1105 57

Two studies of identical design were conducted in battery brooders utilizing male chicks of a commercial strain. The birds were grown to 3 wk on diets with adequate P and from 3 to 6 wk were fed diets ranging from 0.10 to 0.45% nonphytate P (nPP) in increments of 0.05%, with or without supplementation with 800 units of phytase per kilogram of diet. Measurements included BW gain, feed conversion ratio (FCR), mortality, tibia ash, and fecal P content. Nonlinear regression was used to estimate nPP needs for optimizing BW gain, feed conversion, and tibia ash. In the absence of phytase, nPP levels of 0.33, 0.186, and 0.163% were required to optimize tibia ash, BW gain, and FCR, respectively. The estimated level for optimum tibia ash is in close agreement with current NRC (1994) recommendations. In the presence of 800 units of phytase per kilogram, nPP levels of 0.24, 0.151, and 0.109% were needed to optimize tibia ash, BW gain, and FCR, respectively. Fecal phosphorus levels were markedly reduced at the lower P levels. Further studies are needed to determine whether maximum tibia ash values are needed to sustain optimum production of market broilers.
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PMID:Phosphorus requirements of broiler chicks three to six weeks of age as influenced by phytase supplementation. 1129 84

Hens were fed corn-soybean meal diets containing 0.35, 0.25, 0.15, or 0.10% nonphytate phosphorus (NPP) (40 to 60 wk). Phytases A and B were added at 0.25, 0.15, and 0.10% at 250 to 300 units of phytase (FTU)/kg feed in a 3 x 3 factorial; 0.35% was a control diet. Treatments were replicated with eight cages per treatment (five hens per cage) in a randomized complete block design. Phytase supplementation had a significant effect on several production parameters: feed intake, feed conversion, and egg mass. Results showed nonsignificant effects (P < 0.06) on feed intake when hens were supplemented with phytase A or B and consumed more feed compared to the basal diet at 0.10% NPP. The feed conversion of birds fed 0.10% NPP without phytase was the least efficient compared to the other nine treatments (P < 0.05). Egg mass was significantly greater for hens supplemented with phytases A and B than for hens fed the basal diet at low (0.10%) NPP (P < 0.05). There were no significant differences in egg production, egg weight, specific gravity, Haugh units, wet shell, or dry yolk percentages. Dry shell percentage was higher among basal diets at 0.15 and 0.25% NPP in contrast to phytase, whereas albumen and dry yolk percentages were significantly higher for diets with phytase than for the basal diet at 0.10% NPP. Bone ash percentage was uncharacteristically high in hens fed 0.10% NPP without phytase; however, mortality was 22% in this group. Phytase supplementation improved Ca and P digestibilities to varying degrees. Supplementation of phytase in normal, corn-soybean meal diets improved feed intake, feed conversion, and egg mass and elicited a response in shell quality and egg components at the low (0.10%) NPP.
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PMID:Effect of supplementation of two different sources of phytase on egg production parameters in laying hens and nutrient digestiblity. 1159 6


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