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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)

An experiment was conducted to examine the effects of adding microbial phytase (Natuphos) on the performance in broilers fed a phosphorus-adequate, lysine-deficient diet. A wheat-soybean meal-sorghum-based diet, containing 1.00% lysine and 0.45% nonphytate phosphorus, was supplemented with L-lysine monochloride to provide 1.06, 1.12, or 1.18% lysine or with 125, 250, 375, 500, 750, or 1,000 phytase units (FTU)/kg diet. Each diet was fed to six pens of 10 chicks each from Day 7 to 28 posthatching. Addition of lysine to the lysine-deficient diet linearly increased (P < 0.001) weight gain and gain per feed of broilers. The response in weight gain to added phytase reached a plateau at 500 FTU/kg diet (quadratic effect, P < 0.001). Phytase had no effect on gain per feed to 250 FTU/kg diet and then increased (quadratic effect, P < 0.05) with further additions. Assuming that the observed responses in weight gain and gain per feed to added phytase were due to the release of lysine alone and by solving linear or nonlinear response equations of lysine and phytase levels, the lysine equivalency value was calculated to be 500 FTU phytase/kg diet = 0.074% lysine. Addition of increasing levels of supplemental phytase to the lysine-deficient diet improved (P < 0.001) the digestibilities of nitrogen and all amino acids. Phytase also increased the AME, and the response reached a plateau at 750 FTU/kg diet (quadratic effect, P < 0.001). These results showed that amino acid and energy responses are responsible for the performance improvements observed when phytase was added to a wheat-soybean meal-sorghum-based diet.
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PMID:Microbial phytase improves performance, apparent metabolizable energy, and ileal amino acid digestibility of broilers fed a lysine-deficient diet. 1126 65

A significant mechanism of arsenate toxicity to Pisum sativum is interference with its mineral nutrient balance. This conclusion is supported by assessments made after exposing P. sativum L. cv. "Phenomen" for 12 days to 12.5, 20.8, and 33.3 mg, and for 32 days to 7.5, 22.1, 36.7, and 73.3 mg of sodium arsenate/kg dry wt soil in the greenhouse. At 20.8 mg of arsenate, mobilization of manganese from the cotyledons was significantly increased and that of zinc decreased. Nitrogen accumulated in the roots. On Day 32, at 22.1 mg of arsenate, magnesium, zinc, and manganese contents of the roots increased, but that of phosphorus of the shoot decreased. The distribution pattern and the ratios between individual elements were severely altered. Relatively more arsenic accumulated from the low than the high soil concentrations. Growth of the shoot was more affected than that of the roots. After a 32-day exposure, chlorophyll content of the leaves increased, but the chlorophyll a/b ratio decreased. On Day 12, at 12.5 mg and 20.8 mg of arsenate, in vivo phytase activity was 64 and 66% that of the controls, respectively.
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PMID:Arsenate toxicity to Pisum sativum: mineral nutrients, chlorophyll content, and phytase activity. 1138 24

Three experiments were conducted to evaluate P bioavailability, growth performance, and nutrient balance in pigs fed high available P (HAP) corn with or without phytase. The bioavailability of P in normal and HAP corn relative to monosodiumphosphate (MSP) for pigs was assessed in Exp. 1. In a randomized complete block design, 96 pigs (average initial BW 9.75 kg) were fed eight diets for 28 d. The reference and test diets were formulated by adding P as MSP, HAP, or normal corn at 0, 0.75, or 1.5 g/kg to a corn-starch-soybean meal basal diet (2.5 g/kg P) at the expense of cornstarch. Plasma inorganic P concentration responded linearly (P < 0.05) to supplemental P intake. Estimates of P bioavailability from HAP andnormal corn when plasma P was regressed on supplemental P intake were 46 and 33%, respectively. In Exp. 2 and 3, pigs were fed corn-soybean meal-based diets containing HAP corn or normal corn and 0 or 600 units of phytase per kilogram in a 2 x 2 factorial arrangement (two corn sources and two levels of phytase). In Exp. 2, 48 crossbred pigs (barrow:gilt, 1:1) averaging 9.25 kg were used to evaluate growth performance. There were no detectable interactions between corn source and phytase for any of the performance criteria measured. Pigs receiving normal corn had the lowest (P < 0.05) BW and rate of gain. Feed efficiency was lower (P < 0.05) in pigs fed normal compared with those fed the HAP corn phytase-supplemented diet. In Exp. 3, 24 crossbred barrows averaging 14.0 kg were used to evaluate nutrient digestibility. There were no detectable interactions between corn and phytase for any of the N and Ca balance criteria. Nitrogen and Ca retention were improved in pigs receiving HAP corn with phytase (P < 0.05). Retention and digestibility of P was lowest (P < 0.01) for pigs on normal corn diet without phytase. The percentage of P digested and retained was improved and fecal P excretion lowered (P < 0.05) by feeding HAP corn. The results of this study indicate that the bioavailability and balance of P in HAP corn is superior to that of normal corn. The addition of 600 phytase units (Natuphos 600, BASF) to HAP corn-based diets further improved P digestibility and reduced P excretion in pigs.
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PMID:Phosphorus bioavailability, growth performance, and nutrient balance in pigs fed high available phosphorus corn and phytase. 1151 22

Phytases produced by numerous microorganisms and plants degrade phytic acid that has chelated with metal ions in food and feed. It is important to study phytase for the role of metal ions in nutrition of animals and humans as well as in the reduction of organic phosphate content of aqueous environment. This article reports on solid-state fermentation of phytase from a new substrate of cassava dregs. Large quantities of cassava dregs are produced in tropical areas as a byproduct of cassava starch processing. Protein and inorganic salts were found to be low in cassava dregs. Cassava dregs could be employed for phytase synthesis after the addition of a nitrogen source and mineral salts. Ammonium nitrate was the best nitrogen source among the nitrogen sources investigated, including beef extract, yeast extract, urea, ammonium nitrate, sodium nitrate, and ammonium sulfate. Sodium dodecyl sulfate promoted phytase production from cassava dregs. A maximum phytase yield of 6.73 U/g of dry mass was obtained. The obtained phytase was stable at feed-processing temperature, since 70% of initial enzyme activity was maintained after 30 min of treatment at 75 degrees C.
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PMID:Solid-state fermentation of phytase from cassava dregs. 1196 5

Since its discovery in 1907, a complex of technological developments has created a potential $500 million market for phytase as an animal feed additive. During the last 30 years, research has led to increased use of soybean meal and other plant material as protein sources in animal feed. One problem that had to be overcome was the presence of antinutritional factors, including phytate, in plant meal. Phytate phosphorus is not digested by monogastric animals (e.g., hogs and poultry), and in order to supply enough of this nutrient, additional phosphate was required in the feed ration. Rock phosphate soon proved to be a cost-effective means of supplying this additional phosphorus, and the excess phytin phosphorus could be disposed of easily with the animals' manure. However, this additional phosphorus creates a massive environmental problem when the land's ability to bind it is exceeded. Over the last decade, numerous feed studies have established the efficacy of a fungal phytase, A. niger NRRL 3135, to hydrolyze phytin phosphorus in an animal's digestive tract, which benefits the animal while reducing total phosphorus levels in manure. The gene for phytase has now been cloned and overexpressed to provide a commercial source of phytase. This monomeric enzyme, a type of histidine acid phophatase (HAP), has been characterized and extensively studied. HAPs are also found in other fungi, plants, and animals. Several microbial and plant HAPs are known to have significant phytase activity. A second A. niger phytase (phyB), a tetramer, is known and, like phyA, has had its X-ray crystal structure determined. The model provided by this crystal structure research has provided an enhanced understanding of how these molecules function. In addition to the HAP phytase, several other phytases that lack the unique HAP active site motif RHGXRXP have been studied. The best known group of the non-HAPs is phytase C (phyC) from the genus Bacillus. While a preliminary X-ray crystallographic analysis has been initiated, no enzymatic mechanism has been proposed. Perhaps the pivotal event in the last century that created the need for phytase was the development of modern fertilizers after the Second World War. This fostered a transformation in agriculture and a tremendous increase in feed-grain production. These large quantities of cereals and meal in turn led to the transition of one segment of agriculture into "animal agriculture," with their its animal production capability. The huge volumes of manure spawned by these production units in time exceeded both the capacity of their crops and crop lands to utilize or bind the increased amount of phosphorus. Nutrient runoff from this land has now been linked to a number of blooms of toxin-producing microbes. Fish kills associated with these blooms have attracted public and governmental concern, as well as greater interest in phytase as a means to reduce this phosphorus pollution. Phytase research efforts now are focused on the engineering of an improved enzyme. Improved heat tolerance to allow the enzyme to survive the brief period of elevated temperature during the pelletization process is seen as an essential step to lower its cost in animal feed. Information from the X-ray crystal structure of phytase is also relevant to improving the pH optimum, substrate specificity, and enzyme stability. Several studies on new strategies that involve synergistic interactions between phytase and other hydrolytic enzymes have shown positive results. Further reduction in the production cost of phytase is also being pursued. Several studies have already investigated the use of various yeast expression systems as an alternative to the current production method for phytase using overexpression in filamentous fungi. Expression in plants is underway as a means to commercially produce phytase, as in biofarming in which plants such as alfalfa are used as "bioreactors," and also by developing plant cultivars that would produce enough transgenic phytase so that additional supplementation of their grain or meals is not necessary. Ultimately, transgenic poultry and hogs may produce their own digestive phytase. Another active area of current phytase research is expanding its usage. One area that offers tremendous opportunity is increasing the use of phytase in aquaculture. Research is currently centered on utilizing phytase to allow producers in this industry to switch to lower-cost plant protein in their feed formulations. Development of a phytase for this application could significantly lower production costs. Other areas for expanded use range from the use of phytase as a soil amendment, to its use in a bioreactor to generate specific myo-inositol phosphate species. The transformation of phytase into a peroxidase may lead to another novel use for this enzyme. As attempts are made to widen the use of phytase, it is also important that extended exposure and breathing its dust be avoided as prudent safety measures to avoid possible allergic responses. In expanding the use of phytase, another important consideration has been achieved. Conservation of the world's deposits of rock phosphate is recognized as important for future generations. Phosphorus is a basic component of life like nitrogen, but, unlike nitrogen, phosphorus does not have a cycle to constantly replenish its supply. It is very likely that the use of phytase will expand as the need to conserve the world's phosphate reserves increases.
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PMID:Advances in phytase research. 1287 97

1. The influence of a microbial phytase on the performance, toe ash contents and nutrient utilisation of male broilers fed diets based on maize and wheat was investigated. The experiment was conducted as 2 x 2 x 2 factorial arrangement of treatments. Within the factorial, two diet types (maize-soy or wheat-soy) containing two levels of non-phytate phosphorus (3.0 or 4.5 g/kg) were evaluated and each level of non-phytate phosphorus was supplemented with 0 or 500 PU phytase/kg diet. Each of the 8 dietary treatments were fed to 6 pens of 8 birds from d 1 to 21 post-hatching. 2. Main effects of diet type and phytase were observed for all parameters. Main effect of non-phytate phosphorus was significant only for feed/gain and toe ash contents. Phytase addition improved weight gains irrespective of diet type or non-phytate phosphorus level, but the magnitude of improvement in the phosphorus-deficient wheat-soy diet was greater, resulting in a diet type x non-phytate phosphorus interaction. Responses in toe ash contents were noted only in phosphorus-deficient diets, as indicated by a non-phytate phosphorus x phytase interaction. 3. Phytase addition improved apparent metabolisable energy values of wheat-based diets, but had little effect on the apparent metabolisable energy of maize-based diets as shown by a diet type x phytase interaction. The apparent metabolisable energy was not influenced by dietary non-phytate P. 4. Phytase improved ileal nitrogen digestibility in both diet types, but the responses to added phytase tended to be higher in wheat-based diets, as shown by a diet type x phytase interaction. 5. Increasing the dietary non-phytate phosphorus level reduced phosphorus digestibility and increased excreta phosphorus content. Addition of phytase improved phosphorus digestibility, but the increments were higher in low phosphorus diets resulting in a non-phytate phosphorus x phytase interaction. Phytase addition tended to lower the excreta phosphorus content, but the effects were greater in birds fed low phosphorus diets, as shown by a non-phytate phosphorus x phytase interaction.
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PMID:Effects of microbial phytase, produced by solid-state fermentation, on the performance and nutrient utilisation of broilers fed maize- and wheat-based diets. 1496 91

The objective of this study was to evaluate the effect of a combined low-protein, low-phosphorus diet supplemented with limiting amino acids and microbial phytase on performance, nutrient utilization and carcass characteristics of late-finishing barrows. 4 x 8 crossbreed barrows were continuously housed in metabolism cages from 70-110 kg BW and were fed diets, either conventional (A) or protein reduced (B) or protein and phosphorus reduced diets (C) based on barley, maize and soybean meal. Diet A (positive control) contained in air dry matter 13% and 10% CP as well as 0.49% and 0.42% P at growth phases I (70-100 kg BW) or 11 (100-110 kg BW), respectively. Diet B was low in CP (11.3%, 8.4%), diet C low in CP and low in P (CP: as B, P: 0.36%, 0.30%). To diet B the limiting amino acids lysine, methionine, threonine and trypthophan were added to meet the levels in diet A. To diet C the limiting amino acids and 800 FTU/kg Aspergillus-phytase were supplemented. At the end of the balance periods the barrows were slaughtered, the carcasses scored and loin chops, ham and Phalanx prima IV were analysed for nutrients and minerals. The CP or P reduction in diets B and C did not generally negatively affect growth, feed efficiency, absolute nitrogen retention or overall carcass performances of the pigs. With the low CP diets B and C, N excretion per unit BWG was decreased by about 23%. The addition of microbial phytase (diet C) increased apparent total tract digestibility of P by about 20%. In spite of 30% reduction of P intake (diet C), the absolute P retention related to 1 kg BW did not differ between treatments. Thus, phytase supplementation in diet C reduced P excretion per unit BWG by about 33%. Phytase raised apparent digestibility of Zn by about 20% but not Ca digestibility. Generally the carcass traits and meat characteristics were not affected by any of the diet strategies. Mineralization of the Phalanx prima IV was also similar in all treatment groups. However, phytase supplementation led to significantly increased zinc concentration in bones (25%). In contrast, Fe incorporation into the Phalanx prima IV was not affected. In general, the feeding regimen introduced in this experiment offers substantial benefits in maintaining a sustainable environmental-friendly pork production even at the stage of late-finishing barrows.
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PMID:The effect of the combination of microbial phytase and amino acid supplementation of diets for finishing pigs on P and N excretion and carcass quality. 1498 21

1. The effects of myo-inositol hexaphosphate (IP6) and phytase (EC 3.1.3.26) on the excretion of endogenous compounds were investigated using growing broiler chickens. 2. A total of 32 female Ross broilers were used in a precision feeding assay involving a 2 x 2 factorial arrangement of treatments. The materials administered were glucose, glucose + 1000 units of phytase activity (FTU), glucose + 1 g of IP6 and glucose + 1 g of IP6 + 1000 FTU. Excreta were collected quantitatively over a 48-h period following intubation of the test materials. The excretion of nitrogen, amino acids, minerals, sialic acid and phytate phosphorus was determined. 3. The ingestion of 1 g of IP6 by broilers increased the excretion of endogenous nitrogen, amino acids, iron, sodium, sulphur and sialic acid compared with birds fed on glucose. Supplementation of IP6 with exogenous phytase reduced the excretion of endogenous amino acids, calcium, sodium, phytate phosphorus and sialic acid compared with birds fed IP6. 4. It can be concluded that IP6 increases the excretion of endogenous minerals and amino acids in broiler chickens. Part of the beneficial effects of the addition of exogenous phytases to the diets of poultry appears to be mediated through a reduction in endogenous losses of these nutrients.
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PMID:The effects of phytase and phytic acid on the loss of endogenous amino acids and minerals from broiler chickens. 1511 7

Two trials were conducted to evaluate the efficacy of a new microbial phytase (Phyzyme XP) for broiler chicks. Trial 1 used 192 8-d-old male broilers in a 14-d trial to assess growth and nutrient utilization. Dietary treatments (221.9 g/kg CP) included a positive control [5.0 g/kg nonphytate P (NPP)], negative control (1.2 g/kg NPP), and negative control plus 500 or 1,000 phytase units/kg of diet. Phytase addition increased weight gain, feed intake, feed efficiency, and tibia and toe ash (linear, P < 0.01) with tibia ash also responding quadratically (P < 0.05). Apparent ileal digestibility of P (linear and quadratic, P < 0.05), tryptophan, and valine (linear, P < 0.05) also increased. Linear and quadratic responses were observed for retention of DM, nitrogen, P, and several amino acids (P < 0.05) with added phytase. Trial 2 utilized 576 1-d-old male broilers over a 42-d period to evaluate growth performance. Diets were formulated for starter (222.7 g/kg CP) and grower (201.5 g/kg CP) phases and included a positive control (starter and grower, 5.0 and 3.8 g/kg NPP, respectively); negative control (starter and grower, 2.4 and 1.8 g/kg NPP, respectively); negative control plus 500, 750, or 1,000 phytase units/kg; and negative control plus 500 phytase units/kg of Natuphos phytase. Phytase increased weight gain and feed intake (starter, grower, overall) as well as feed efficiency during the starter period (linear, P < 0.05). Feed intake was also improved during the grower period and overall (quadratic, P < 0.05). Tibia and toe ash of birds fed for the first 21 d increased (linear, P < 0.05) with tibia ash also increasing quadratically (P < 0.05). Overall, tibia and toe ash were improved due to phytase addition (linear and quadratic, P < 0.05). In conclusion, this microbial phytase, derived from Escherichia coli and expressed in Schizosaccaromyces pombe, elicited improved growth performance, bone mineralization, and P utilization in broiler chicks.
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PMID:Evaluation of microbial phytase in broiler diets. 1520 23

The global livestock population is estimated to be close to 4 billion animals, and to produce around 500 million tons of manure annually (Baidoo, 2003). This is expected to increase in the future with the projected greater demand for meat for human consumption. The problem of manure disposal is exacerbated by the concentration of animal production in increasingly large units, to obtain economies of scale and keep up with the demand for cheap food. The primary environmentalfactors are manure volume, manure nitrogen and phosphorus contents, methane production and odour (Jongbloed and Lenis, 1998). Legislation in many regions now restricts the amount of manure that can be applied per hectare, to prevent environmental pollution (Centner, 2001; Pellini and Morris, 2001). There are a number of strategies the animal production industry can take to reduce environmental impact. These include taking steps to improve the efficiency of conversion of feed into edible products, reduce feed wastage and formulate diets that more closely satisfy animal requirements for specific nutrients. At present 50-80% of the nitrogen and phosphorus fed to animals are not utilized but are excreted via manure and urine to the environment (Baidoo, 2003). Biotechnology could play a very important role in reducing the environmental impact of animal production. Examples include the development of animals more efficient at converting nutrients into edible products, and of higher quality, more digestible feedstuffs. Biotechnology can also be used to produce a range of feed additives that can improve the efficiency of animal production, including for example recombinant somatrophin, amino acids and enzymes. This paper summarizes a series of four experiments looking at the effects of microbial xylanase or phytase supplementation on excretion in swine and poultry. This summary indicates that the inclusion of these enzymes in animal feeds can reduce manure volume by up to 14%, and nitrogen and phosphorus outputs by up to 13% and 70%, respectively.
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PMID:Reducing environmental pollution using animal feed enzymes. 1529 79


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