Presence Of Phytase Research Articles

Effects of dietary calcium and microbial phytase on the bioavailability of two sources of zinc in broilers

ABSTRACT 1. The objective of this study was to test the effect of microbial phytase and calcium (Ca) levels on the Zn bioavailability depending on the Zn source. 2. A total of 144, one-day-old broilers received a diet containing 40 mg Zn/kg for 1 week. They were then assigned to one of the eight experimental treatments during 2 weeks. Diets contained 27 mg native Zn and were formulated according to a 2 × 2 × 2 factorial design with two added Zn sources (23 mg Zn/kg), sulphate (ZnSO4) or oxide (ZnO); two dietary Ca levels of either 6 (low) or 10 g/kg (moderate); and two microbial phytase levels, of either 0 or 750 phytase unit/kg. 3. Moderate Ca plus phytase improved body weight gain (BWG) and low Ca level without microbial phytase decreased tibia weight (Ca × Phy; p = 0.049). Zinc oxide resulted in a higher tibia development (i.e. tibia weight and length; p < 0.05) and BWG (p = 0.009) and lower FCR (p < 0.001) compared to ZnSO4. 4. Phytase improved tibia Zn concentration especially in birds given ZnSO4 compared to ZnO (Zn × Phy; p = 0.049). Moderate Ca diets improved tibial characteristics and Zn deposition compared to low Ca diets (p < 0.05). 5. Soluble Zn in the gizzard increased in the presence of phytase (p = 0.011), while higher dietary Ca reduced this in birds receiving ZnO (p = 0.004). In the jejunum, Zn solubility was higher with phytase (p = 0.008). 6. Under the conditions of this study, dietary levels of Ca and microbial phytase affect Zn availability in broilers more than the Zn source.

256 Evaluation Calcium and Phosphorus Ratios in the Presence of Phytase on Performance and Whole-Body Bone Mineralization in Growing Pigs

Abstract The objective of this study was to evaluate the effects of dietary calcium and phosphorus ratios in the presence of super dose phytase on grower pigs growth performance and bone mineral density. In two replicates, a total of 48 mixed sex pigs (26.7 kg BW) were allotted by BW and sex into individual pens across 3 dietary treatments (16 pigs/treatment) for 28 days. All diets contain phytase at 1,500 FTU/kg of complete feed and the three diet treatments were formulated with differing levels of Ca to achieve 0.7, 1.1 and 1.5 total Ca:total P. All diets were formulated to be isocaloric and isonitrogenous and ratios were achieved by vary limestone and sand. Pig BW and feed disappearance were recorded at the start (d 0) and end (d 28) of the study to calculate ADG, ADFI and G:F. On day 28, all pigs were euthanized to determine whole body bone, foot, rib, femur and tibia bone mineral density via dual x-ray absorptiometry. Data were analyzed with pen as the experimental unit, fixed effect of dietary treatment, sex and their interaction, and initial BW block and repartition as random effects. Differences were determined significant at P ≤ 0.05. Pig ADG was increased in the 1.1 verses 0.7 and 1.5 Ca:P diets (1.01, 0.95 and 0.95 kg/d, respectively, P = 0.046). End body weight was not different in the 0.7, 1.12 and 1.5 Ca:P treatments (53.5, 54.8 and 53.1 kg, respectively, P = 0.106). Diet Ca:P ratio did not alter ADFI or G:F. Whole body, tibia and femur bone mineral density was increased by 110% in 1.5 verses 0.7 Ca:P fed pigs, with bone mineral density being intermediated in the 1.1 Ca:P diets. Whole body (0.740, 0.752, 0.797, g/cm2, for 0.7, 1.1 and 1.5 Ca:P respectively, P = 0.033). For 0.7, 1.1 and 1.5 Ca:P femurs, bone mineral density was 0.463, 0.498 and 0.516, respectively, P = 0.034). Dietary treatment did not alter whole foot or 10th rib bone mineral densities (P &amp;gt; 0.05). Sex did not affect pig performance, but gilts had a 9% increase in bone mineral content. In conclusion, formulating dietary Ca:P in the presence of super dosing phytase at 1.1:1 total Ca:P resulted in the best ADG, but a ratio of 1.5:1 had the greatest bone mineral density.

Dietary phytase effects on copper requirements of broilers.

Information on the availability of Cu from plant feedstuffs for broilers in the presence of phytase is scarce. The present research has been conducted with the objective of evaluating the Cu requirements of broilers when fed corn-soy diets with or without phytase. A total of 640 one-day-old male Cobb x Cobb 500, allocated into 80 battery cages with 8 chicks in each, were fed a low Cu content diet (formulated with 8.58 ± 0.21 mg/kg Cu) without phytase from placement to day 7. Starting on day 8, battery cages were distributed into a 2 × 5 factorial arrangement (phytase-added diets X 5 with graded increases of supplemental Cu) until day 28. Feeding treatments (feeds added or not with phytase and 5 graded increases of Cu) were randomly distributed with 8 cages of 8 chicks. The basal non-supplemented feeds were formulated with corn and soybean meal (SBM) without any other significant Cu contributors. Supplemental Cu was from laboratory-grade Cu sulfate pentahydrate (CuSO5H20) which was increasingly added to the feeds. Phytase was added in excess to the producer recommendation (2,500 FYT) and had average analyzed values of 2,768 ± 135.2 FYT/kg whereas analyzed Cu values were: 8.05 ± 0.25, 11.25 ± 0.15, 14.20 ± 0.40, 16.55 ± 0.05, and 19.45 ± 0.45 mg/kg. Statistics were conducted using linear and quadratic polynomial regression models. No interactions occurred between dietary Cu and phytase (p > 0.05) for any response and no effects were found for the individual factors (phytase or dietary Cu) for Ht, Hb, varus, valgus, rotated tibia, and tibia breaking strength, as well as for Cu contents in breast, gastrocnemius tendon, and kidney (p > 0.05). However, the phytase-added diets led to higher BWG, lower FCR, and increased ileal digestible Cu (p < 0.05). The gradual increase in dietary Cu produced linear increases in Cu content in livers, as well as in excreta and retention (p < 0.05). Supplementing phytase at levels expected to maximize phytate degradation was demonstrated to improve BWG and FCR; however, no effects were observed when dietary Cu was increased to a maximum of 19.45 mg/kg. An increase of 8.8% in ileal digestible Cu was observed when birds were fed phytase.

Effect of sodium sources and exogenous phytase supplementation on growth performance, nutrient digestibility, and digesta pH of 21-day-old broilers

The effect of sodium chloride (NaCl) and NaCl+sodium hydrogen carbonate (NaHCO3) and supplemental phytase (0, 500, 1,000, and 2,000 FTU/kg) on performance, nutrient digestibility and utilization, and digesta pH of male broiler chickens were investigated in a 2 × 4+1 factorial arrangement of treatments in a completely randomized design with 6 replicate cages of 8 birds per replicate. Data were analyzed as a 2 × 4 factorial with contrast between the positive control and the diets containing 0 FTU phytase. Phytase supplementation linearly improved (P < 0.05) average body weigh gain (BWG) and feed intake (d 0–14 and 0–21). Apparent jejunal dry matter (DM) digestibility and digestible energy in birds fed diets containing only NaCl increased (linear and quadratic; P < 0.05) with phytase supplementation whereas quadratic (P < 0.05) effect was observed in birds fed diets containing a combination of NaCl and NaHCO3. Phytase supplementation improved (linear and quadratic; P < 0.05) apparent ileal nitrogen and P digestibility. Apparent utilization of DM, nitrogen, energy, and metabolizable energy increased (linear; P < 0.05) with increasing level of phytase supplementation. Apparent P utilization increased (linear and quadratic; P < 0.05) for both sodium sources but calcium utilization only increased (linear; P < 0.05) with the combination of NaCl and NaHCO3. Bone breaking strength (linear and quadratic) and bone ash (linear) increased (P < 0.05) with phytase supplementation. The combination of NaCl and NaHCO3 resulted in lower (P < 0.05) pH of digesta in the proximal ileum whereas the pH of the digesta in the distal ileum (linear) and the average pH of ileal contents (linear and quadratic) increased (P < 0.05) with phytase supplementation. Results from this study showed that birds’ performance and utilization of nutrients and energy by broilers in the presence of phytase was, in general, not influenced by the source of sodium in the diet. Data from this study showed that NaHCO3 can replace a portion of NaCl in the diet of broilers supplemented with phytase without any significant negative effect on performance and that the 2,000 FTU phytase level resulted in better BWG and feed intake as well nutrient and energy utilization.

Formulation of diets for pigs based on a ratio between digestible calcium and digestible phosphorus results in reduced excretion of calcium in urine without affecting retention of calcium and phosphorus compared with formulation based on values for total calcium.

An experiment was conducted to test the hypothesis that formulating diets for pigs based on a ratio between standardized total tract digestible (STTD) Ca and STTD P instead of total Ca and STTD P does not decrease Ca retention, but increases P utilization. Forty barrows (59.4 ± 3.8 kg) were individually housed in metabolism crates and allotted to four corn-soybean meal-based diets in a randomized complete block design with two blocks and five pigs per diet in each block. Diets were formulated using a 2 × 2 factorial design with two diet formulation principles (total Ca or STTD Ca) and two inclusion levels of microbial phytase (0 or 500 units per kg of feed). Phytase was assumed to release 0.11% STTD P and 0.16% total Ca. Diets were formulated based on requirements for total Ca and STTD P or a ratio between STTD Ca and STTD P of 1.25:1. Diets were fed for 11 d and fecal and urine samples were collected from feed provided from day 6 to day 10. Interactions (P < 0.05) between diet formulation principle and phytase level were observed for Ca intake, Ca in feces, Ca absorbed, Ca retained, P digestibility, P absorbed, and P in urine. Phytase increased (P < 0.05) the digestibility of Ca in both total Ca and STTD Ca diets. Without phytase, Ca intake, Ca in feces, and Ca absorbed was greater (P < 0.05) from pigs fed total Ca diets than from pigs fed STTD Ca diets, but P absorbed, P digestibility, and P in urine was greater (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. However, in the presence of phytase, no differences between diet formulation principles were observed in these variables. Regardless of phytase, Ca in urine was lower (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. There were no differences in Ca retention between pigs fed STTD Ca diets and total Ca diets, but pigs fed total Ca diets retained less (P < 0.05) Ca if diets contained phytase. No differences in P retention were observed between diet formulation principles, but pigs fed non-phytase diets retained more (P < 0.05) P than pigs fed diets with phytase. In conclusion, because diets formulated based on STTD Ca contain less Ca than total Ca diets, pigs fed STTD Ca diets excreted less Ca in urine, but retention of Ca was not affected. Formulating non-phytase diets based on STTD Ca instead of total Ca increased P absorption, which confirms the detrimental effect of excess Ca on P digestibility. However, P retention was not improved if pigs were fed STTD Ca diets.

Effects of a complex phytase-containing enzyme preparation on the rye wort fermentation process

A complex of amylases, proteases, and hemicellulases is known to enhance deep conversion of polysaccharides and proteins, especially in the processing of difficult-to-ferment raw materials, such as rye, providing grain wort with soluble carbohydrates, amino acids, and peptides. Grain is also a source of phosphorus, whose bioavailability can be increased by hydrolysing the grain with phytase-containing enzyme preparations. However, their catalytic action during the preparation of grain wort for alcohol production has hardly been studied. This study aimed to investigate the effect of a new complex phytasecontaining enzyme preparation on yeast metabolism and the efficiency of rye wort fermentation. The work was carried out in the Russian Research Institute of Food Biotechnology. The Glucavamorin complex enzyme preparations derived from recombinant strains were the object of our research. The preparations differed in the activity level of the main enzyme, lucoamylase, and minor hemicellulase enzymes, as well as in the presence of phytase. The results confirmed their biocatalytic ability to efficiently hydrolyse polymers of rye grain. An increased content of hemicellulases in Glucavamorin-Xyl improved the rheological properties of rye wort. The greatest effect was achieved with the phytase-containing Glucavamorin-Ply. This preparation improved the phosphorus nutrition of yeast, which increased its biomass by 30% and decreased the level of fermentation by-products by 18–20%. Alcohol yield tended to increase and its strength reached 10.5–10.9% vol. When using a phytase-containing enzyme complex, it was possible to reduce the amount of the main enzyme, glucoamylase, without causing the key fermentation indicators to degrade.

Influence of phytase enzyme on ruminal biogas production and fermentative digestion towards reducing environmental contamination.

Environmental impact of livestock production has received a considerable public scrutiny because of the adverse effects of nutrient run-offs, primarily N and P, from agricultural land harboring intensive energy livestock operations. Hence, this study was designed to determine the efficacy of dietary phytase supplementation on fermentation of a sorghum grain-based total mixed ration (TMR) using a ruminal in vitro digestion approach. Phytase was supplemented at three doses: 0 (control), 540 (P540), and 720 (P720)g/t dry matter, equivalent to 0, 2.7 × 106, and 3.6 × 106 CFU/t DM, respectively. Compared to P720 and the control, gas production was higher for P540 after 12h (P= 0.02) and 24h (P= 0.03) of fermentation suggesting a higher microbial activity in response to phytase supplementation at lower phytase levels. Correspondingly, dry matter degradability was found to have improved in P540 and P720 compared to the control by 13 and 11% after 24h of incubation (P= 0.05). For ammonia nitrogen (NH3-N), a tendency towards lower values was only observed for P540 at 24h of fermentation (P= 0.07), while minimal treatment effects were observed at other fermentation times. The concentrations of total volatile fatty acids (VFA) were higher (P< 0.05) after 48h of fermentation for P540 and P720 compared to the control (P= 0.03) by 10% and 14%, respectively. Ruminal acetate tended towards higher values in the presence of phytase after 12h of fermentation (P= 0.10), but towards lower values after 24h of fermentation (P= 0.02), irrespective of the phytase dose applied. A trend towards lower ruminal propionate levels was observed in the presence of phytase after 6h (P= 0.10) and 12h (P= 0.06) of fermentation, while no effects were found at other fermentation times. In conclusion, phytase supplementation has the potential to improve metabolic energy activity of rumen microorganisms and the use of feed constituents. Thus, phytase supplementation could help to reduce environmental contamination in areas of ruminant production.

Effects of limestone particle size and dietary Ca concentration on apparent P and Ca digestibility in the presence or absence of phytase

The present study evaluated the effects of limestone particle size and Ca concentration on apparent ileal digestibility (AID) of P and Ca in the presence or absence of a 6-phytase derived from Buttiauxella sp., expressed in Trichoderma. Treatment diets were corn-soybean meal (SBM) based with no added inorganic Ca or P. The design consisted of a factorial arrangement of 2 particle sizes of limestone from the same source (mean particle size: pulverized, PUV < 75 μm; particulate, PAR = 402 μm); 3 Ca (0.6, 0.8, and 1.0%) and 2 phytase levels (0 and 1,000 (FTU)/kg) plus the corn-SBM basal diet with no added Ca (0.14% Ca), resulting a total of 13 treatments (Trts, n = 9, 3 birds/n). Starting at 27 d of age, broilers were fed the mash diets for 32 h, then sampled for gizzard pH and distal ileal digestibility. Gizzard pH was 1.94 in birds fed diet without added Ca and was similar to those fed diet with PAR limestone regardless of phytase. Gizzard pH was increased in birds fed PUV limestone diets irrespectively of phytase inclusion compared to birds fed 0.14% Ca (P < 0.05), except in birds fed 0.60% Ca diet. In the absence of phytase, AID P was reduced as a result of increases in limestone inclusion (P < 0.05), with a greater effect seen in PUV as compared to PAR limestone. The AID Ca in birds fed PUV limestone diets was lower than that of those fed PAR limestone diets (22.1% vs. 28.2%; P < 0.05). In the presence of phytase, the AID P was not affected by increasing Ca concentration when PAR limestone was used as the Ca source (average = 64.3%), whereas AID P decreased from 66.9% (0.6% Ca) to 51.0% (1.0% Ca) when PUV limestone was used as the Ca source (P < 0.05). In summary, impact of Ca concentration on AID Ca and P was dependent on limestone particle size and phytase inclusion.

High doses of phytase on growth performance and apparent ileal amino acid digestibility of broilers fed diets with graded concentrations of digestible lysine.

Two experiments of the same design were conducted to determine the influence of phytase on performance and apparent ileal digestibility (AID) of amino acids in broilers fed graded concentrations of digestible lysine (dgLys). Cobb 400, male broilers were allocated to 1 of 16 diets consisting of 4 basal diets formulated at 80, 88, 96, or 104% of the Cobb 400 dgLys requirements for each feeding phase. Phytase was included in each basal diet at 0, 750, 1,500, or 3,000 phytase units (FTU)/kg. In Exp. 1, 33 birds/pen from hatch to day 42 were fed a 2-phase feeding program with 12 replicate pens/diet. In Exp. 2, there were 25 birds/pen from hatch to day 21 and 8 replicate pens/diet. Data were analyzed as a 4 × 4 factorial and means separated using orthogonal contrasts. In Exp. 1, feed intake (FI) increased (quadratic, P < 0.05) as dgLys increased in the diet. Body weight gain (BWG) increased (quadratic, P < 0.05) as dgLys concentration or phytase dose increased in the diet. As phytase dose increased in the diet, feed conversion ratio (FCR) was improved in a linear or quadratic (P < 0.05) manner depending on the dgLys concentration of the diet (dgLys × phytase, P<0.05). In Exp. 2, FI linearly (P < 0.05) increased as dgLys increased in the diet. Increasing the concentration of dgLys or phytase in the diet increased (quadratic, P < 0.05) BWG and improved (quadratic, P < 0.05) FCR. The AID of most amino acids was influenced by a dgLys × phytase interaction (P < 0.05), except threonine, valine, tryptophan, serine, cysteine, or leucine (linear or quadratic effect of phytase, P < 0.05), where phytase improved the AID in birds fed diets containing 80, 88, or 96% of the dgLys requirement, but not birds fed 104%. The predicted dgLys requirement to maximize performance, carcass, and digestible lysine intake was 97.6 to ≥ 104%. The predicted dose of phytase to maximize BWG or FCR was between 1,990 and 2,308 FTU/kg, regardless of the dgLys concentration in the diet. The predicted dose of phytase to maximize carcass weight was between 1,527 and 2,658 FTU/kg of diet and to maximize breast weight was 0 to ≥ 3,000 FTU/kg diet, depending on the dgLys concentration in the diet. In conclusion, optimal performance in the absence of phytase could be achieved at much lower levels of lysine in the presence of phytase.

Interactive effects of phosphorus, calcium, and phytase supplements on products of phytate degradation in the digestive tract of broiler chickens

This study aimed to distinguish between the single and interactive effects of phosphorus (P), calcium (Ca), and phytase on products of phytate degradation, including the disappearance of myo-inositol (MI), P, Ca, and amino acids (AA) in different segments of the digestive tract in broiler chickens. Additionally, all dephosphorylation steps from myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) to MI were investigated in the digesta of the terminal ileum. Unsexed Ross 308 broiler chickens were allocated to 56 pens with 19 birds per pen, and assigned to one of 8 dietary treatments. The dietary treatments included diets without (P−, 4.1 g/kg DM) or with (P+, 6.9 g/kg DM) monosodium phosphate supplementation, without (Ca−, 6.2 g/kg DM) or with (Ca+, 10.3 g/kg DM) additional fine limestone supplementation, and without or with 1,500 FTU phytase/kg feed in a factorial design. Adding Ca or P had no effect on InsP6 disappearance in the crop when phytase was added. InsP6 disappearance up to the terminal ileum (P−Ca− 56%) was decreased in P+Ca− (40%), and even more so in P+Ca+ (21%), when no phytase was added. Adding phytase removed all effects of P and Ca (77 to 87%); however, P+Ca+ increased the concentrations of lower InsP esters and reduced free MI in the ileum, even in the presence of phytase. These results indicate that mineral supplements, especially P and Ca combined, reduce the efficacy of endogenous microbial or epithelial phosphatases. Supplementation with phytase increased, while supplementation with Ca decreased the concentration of MI in all segments of the digestive tract and in blood plasma, demonstrating the ability of broilers to fully degrade phytate and absorb released MI. While AA disappearance was not affected by P or Ca, or an interaction among P, Ca, and phytase, it increased with the addition of phytase by 2 to 6%. This demonstrates the potential of the phytase used to increase AA digestibility, likely independent of P and Ca supply.

Interaction between xylanase and phytase on the digestibility of corn and a corn/soy diet for broiler chickens

An experiment was carried out to evaluate the digestibility and metabolizability of corn and a corn/soy-based diet with the inclusion or not of xylanase and/or phytase in broilers. In the trial, 1,120 broiler chicks were distributed according to a completely randomized experimental design, consisting of 16 treatments, with 10 replicates of 7 birds each. Treatments were evaluated following a factorial arrangement (4 × 2 × 2), with 4 xylanase levels (zero, 50, 100, or 150 fungal β-xylanase units/kg; FXU), 2 phytase levels (zero or 1,000 phytase units/kg; FTU), and 2 diets (corn/soy or pure corn). The same basal diets were fed from one to 14 d post hatch for all birds, after which the experimental diets were provided until d 25. All birds were euthanized on d 25 for collection of ileal contents. Samples of feed, excreta, and ileal digesta were analyzed for determination of apparent ileal digestibility. The effect of xylanase on the coefficient of apparent dry matter metabolizability and apparent metabolizable energy was increased by the presence of phytase in the complete diet but not in the diet based on pure corn resulting in a diet* phytase* xylanase interaction (P < 0.01; P < 0.001, respectivaly). Equivalent effects were observed for the apparent coefficient of ileal protein digestibility in which xylanase effects were potentiated by the presence of phytase only in the complete diet, resulting in a significant 3-way interaction. In corn there was a limitation in improving digestibility when we added increasing levels of xylanase with phytase. Otherwise in the corn/soy-based diets, the enzymes were potencialized when they were added together. The fact that the effect of xylanase was enhanced by the presence of phytase in complete diets but not in pure corn may be associated with differences in substrate (arabinoxylan and/or phytate) concentration and presentation, diet nutrient balance, or other factors. It can be concluded that the interactive effects of xylanase and phytase can be substantial but may depend on the characteristics of the diet fed.

Phosphorus digestibility response of growing pigs to phytase supplementation of triticale distillers' dried grains with solubles.

An experiment was conducted in growing pigs to determine the true total-tract digestibility (TTTD) of P in triticale distillers' dried grains with solubles (DDGS) with or without phytase using the regression method. Six diets were formulated in a 3 × 2 factorial arrangement, including 3 levels of triticale DDGS (300, 400, or 500 g/kg) and phytase (0 or 500 phytase units [FTU]/kg of diet). A total of 48 barrows (initial BW 22.2 ± 1.3 kg) were assigned to the 6 diets in a randomized complete block design. There was a 5-d adjustment period followed by a 5-d total collection of feces. The results show that P intake, fecal P output, and digested P increased linearly ( < 0.01) with increasing level of DDGS in diets. There was a main effect ( < 0.001) of phytase on apparent total-tract digestibility (ATTD) of P. In diets without added phytase, the ATTD of P in triticale DDGS was 65.0, 67.7, and 63.2% for the diets with 300, 400, and 500 g/kg triticale DDGS, respectively; the corresponding values for diets with added phytase were 77.3, 76.3, and 75.7%. By regressing daily digested P against daily P intake, the TTTD of P was estimated at 75.4% for triticale DDGS or 81.1% with added phytase, respectively. In conclusion, the TTTD of P in triticale DDGS without supplemental phytase was 75.4%, and it was 81.1% in the presence of phytase at 500 FTU/kg of the diet, but the difference was not statistically significant. For triticale DDGS, the supplementation of 500 FTU/kg phytase in diet could increase the ATTD of P ( < 0.001) but not the TTTD of P.

Reduction of Phosphorus Pollution from Broilers Waste through Supplementation of Wheat Based Broilers Feed with Phytase

The present study was conducted to reduce phosphorus pollution from broilers waste by supplementing phytase enzyme in broilers fee. Two hundred two-week-old broilers (Hubbard) were selected and randomly allocated to three dietary treatment groups, one control group (without phytase) and two trial groups (group A with 300 U/kg phytase and group B with 600 U/kg phytase). Each group was composed of 5 replicates with 10 chicks. Broilers fed the control diet (without phytase) gained weight slower (P&lt; 0.05) than the other treatment groups. A significant increase in body weight gain of group A (28.00 ± 2.97) and group B (29.75 ± 3.45) was observed as compared to control group (26.75 ± 2.78). The feed intake of the birds fed the diets containing microbial phytase 600 U/kg was the highest. Phytase significantly (P&gt; 0.05) reduces excreta P and Ca level. Phytase addition did not affect excreta pH. The presence of phytase in feed mixtures significantly (P&gt; 0.05) improves the body weight gain and feed intake of broiler chickens.

The presence of phytase in yeasts isolated from the gastrointestinal tract of four major carps [Labeo rohita (Hamilton, 1822), Catla catla (Hamilton, 1822), Cirrhinus mrigala (Hamilton, 1822), Hypophthalmichthys molitrix (Valenciennes, 1844)], climbing pe

Phytic acid (myo-inositol 1, 2, 3, 4, 5, 6-hexakis dihydrogen phosphate), a plant-derived anti-nutritional factor, is the major phosphorus (P) storage compound in plant feedstuffs. The presence of phytic acid restricts incorporation of various plant ingredients in formulated diets because it chelates nutritionally important minerals, proteins and amino acids, thereby rendering them biologically unavailable to the animals (Pointillart et al., 1987), including fish (Cho and Bureau, 2001), due to the lack of intestinal phytase. Phytase (myoinositol hexakisphosphate phosphohydrolase, EC 3.1.3.8) initiates the release of phosphate from phytic acid, and thus assists in the degradation of phytate compounds (Oatway et al., 2001). Phytases have a wide distribution in plants, microorganisms and some animal tissues (Vohra and Satyanarayana, 2003). Phytase produced by microbiota in the gut increases the availability of phosphorus and other important nutrients in ruminants (Selinger et al., 1996; Yanke et al., 1998) by virtue of enzymatic hydrolysis of the phytic acid. Although the specific role of the colonizing microorganisms in the gastrointestinal (GI) tract of fish is unclear, attention to identify groups of autochthonous microorganisms has been given to gain information on activities of the microbiota (Cahill, 1990). In this context, the importance of the commensal exo-enzyme producing microbiota within GI tracts of fish has been emphasized during the past decade (for review see Ray et al., 2012). Some of these recent investigations have called attention to the possibility of phytate degradation through the action of phytases produced by microbiota in the fish gut. Reports on the presence of phytase-producing microorganisms in the GI tracts of marine (Li et al., 2008; Askarian et al., 2012) and freshwater fishes (Roy et al., 2009; Khan et al., 2011; Khan and Ghosh, 2012) are available. Although most of those studies emphasized bacteria, Li et al. (2008) documented the phytase-producing marine yeast strain Kodamea ohmeri BG3 from the gut of a marine fish, Hexagrammes otakii. To our knowledge, occurrence of phytase-producing yeasts in the GI tract of freshwater fishes has yet to be evaluated, with efforts generally still in their infancy. This preliminary study therefore intended to (i) detect autochthonous phytase-producing yeasts, if any, in the GI tracts of six freshwater teleosts, (ii) screen potentially phytase-producing yeasts through in vitro quantitative phytase assay, and (iii) identify the most promising strains by 28S rDNA sequence analysis.

Phytases and &lt;i&gt;myo&lt;/i&gt;-inositol modulate performance, bone mineralization and alter lipid fractions in the serum of broilers

Under conditions simulating intestinal digestion in broilers, phytase B was found to free myo-inositol from low non-phytate phospho- rus maize-soyabean meal-based and wheat-soyabean meal-based diets, whereas both 3- and 6-phytases A accelerated myo-inositol release only in the presence of phytase B. In the feeding experiment, myo-inositol at 1 g · kg -1 increased the feed intake and body weight gain of broilers fed both types of feeds. Phytase B at 1300 acid phosphatase units (AcPU) · kg -1 enhanced feed consumption, body weight gain, and tibia mineralization, whereas phytase B mixed with 6-phytase A at 500 phytase units (FTU) · kg -1 produced further en- hancements in performance and bone mineralization. After 6 weeks, broilers fed the maize-based diets supplemented with both phytase B and 6-phytase A had increased serum concentrations of triglycerides and HDL-cholesterol, as well as an enhanced HDL/total cholesterol ratio. The increases in this ratio cannot be attributed to the release of phosphorus or to the generation of myo- inositol by the supplemented enzymes, but can only be explained as effects of intermediate products of phytate dephosphorylation.

Evaluation of a highly soluble calcium source and phytase in the diets of broiler chickens

An experiment was conducted to evaluate the influence of a highly soluble Ca (HSC) source on performance, bone ash and mineralization, and apparent ileal digestibility of Ca, P, N, and energy in Ross 708 broiler chickens. Dietary Ca was supplied by the HSC source and monocalcium phosphate to provide 4 levels of Ca (0.45, 0.60, 0.75, or 0.90%). Available P (aP) was maintained at 0.32% in all the diets. Each diet was supplemented with 0, 500, or 2,500 U/kg of phytase as a 4 × 3 factorial. An additional diet was formulated using limestone to contain 0.90% Ca and 0.45% aP as a positive control (PC). Diets were fed to 7 replicate cages of 8 birds per cage from d 0 to 21 posthatch. Feed intake (FI) was linearly (P ≤ 0.05) reduced, and BW gain was quadratically (P ≤ 0.05) reduced as Ca from HSC increased from 0.45 to 0.90%. Phytase supplementation linearly (P ≤ 0.05) increased FI and BW gain and improved feed conversion ratio. Tibia ash and P weights were lower in birds fed 0.90% Ca from HSC compared with broilers fed 0.90% Ca from limestone. Phytase supplementation increased tibia ash and P weights in broilers fed 0.60, 0.75, or 0.90% HSC (Ca level × phytase P ≤ 0.05). Phytase supplementation linearly (P ≤ 0.05) increased tibia Ca weight. Reducing HSC from 0.90 to 0.45% or increasing phytase supplementation linearly (P ≤ 0.05) improved ileal P digestibility. Ileal Ca digestibility increased linearly only in broilers fed 0.45% Ca from HSC as phytase supplementation increased (Ca level × phytase P ≤ 0.05). Nitrogen or energy digestibility were quadratically (P ≤ 0.05) influenced as HSC or phytase increased. In conclusion, feeding HSC with phytase allowed for reductions in dietary Ca while maintaining broiler performance and bone ash. In addition, P digestibility and P in the bones were increased in broilers fed reduced dietary Ca in the presence of phytase.

The ability of laying hens to regulate phosphorus intake when offered two feeds containing different levels of phosphorus.

The ability of laying hens to adjust their intake of available P (AP) was investigated with a maize-soyabean diet fed to forty-eight individually caged birds in a 2 x 4 factorial experiment. From 19 to 25 weeks of age (phase 1) twenty-four birds were fed a normal-P (NP) diet (2.2 g AP/kg DM) and twenty-four were fed a low-P (LP) diet (1.1 g AP/kg). LP eggs were lighter (51 v. 54 (SEM 1.0) g; P<0.05), providing evidence that the LP diet was deficient in AP. From 25 to 28 weeks of age six hens from each phase 1 treatment were fed either the NP or LP diet alone or a choice of the LP and NP feeds or a choice of the LP feed and a phytase-supplemented (PP) feed (LP diet with 400 microbial phytase units/kg). With a choice of the NP and LP feeds, the hens fed the LP diet in phase 1 ate a smaller proportion of the LP feed (34 (SEM 12.0) %) than the hens fed the NP diet in phase 1 (72 (SEM 12.0) %; P<0.05), showing that P deficiency influenced subsequent selection for AP, i.e. an appetite for P was demonstrated. In those birds offered the LP and PP feeds, the presence of phytase in one of the two feeds significantly alleviated the effect of P deficiency on egg and body weights. The proportion of the LP diet chosen was not significantly affected by phase 1 treatment; it was not necessary for the hens to eat more than 50 % of PP feed.

A comparison between cholecalciferol and 25-OH-cholecalciferol on performance and eggshell quality of hens fed different levels of calcium and phosphorus

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 × 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 × 2 × 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.

A four-step enzymatic cascade for the one-pot synthesis of non-natural carbohydrates from glycerol.

A total of four enzymatic steps were combined, in a one-pot reaction, to synthesize carbohydrates starting from glycerol. First, phosphorylation of glycerol by reaction with pyrophosphate in the presence of phytase at pH 4.0 in 95% glycerol afforded racemic glycerol-3-phosphate in 100% yield. The L-enantiomer of the latter underwent selective aerobic oxidation to dihydroxyacetone phosphate (DHAP) at pH 7.5 in the presence of glycerolphosphate oxidase (GPO) and catalase. Subsequently, fructose-1,6-bisphosphate aldolase catalyzed the aldol reaction of DHAP with butanal. Finally, dephosphorylation of the aldol adduct was mediated by phytase at pH 4 affording 5-deoxy-5-ethyl-D-xylulose in 57% yield from L-glycerol-3-phosphate. The phytase on/off-switch by pH was the key to controlling phosphorylation and dephosphorylation.

Nonphytate phosphorus requirement of laying hens with and without phytase on a phase feeding program

An experiment was conducted to reevaluate the nonphytate P (NPP) requirement of laying hens with and without phytase. The experiment involved 12 treatments in a 6 x 2 factorial design. The hens of the control group (T1) were fed a sequence of 0.40-0.35-0.30% NPP during 30 to 42, 42 to 54, and 54 to 66 wk, respectively. The NPP was reduced in increments of 0.05% in T2 to T6. The hens of T7 to T12 were fed NPP regimens similar to T1 to T6 but with 300 units phytase/kg diet. Two digestion trials were conducted during 42 and 66 wk, and nitrogen, phytate, and total P retention were determined. In the absence of phytase, production traits were not different for hens fed a NPP regimen of 0.25-0.20-0.15% than for the unsupplemented phytase control group for the entire experiment (P > 0.05). However, production traits were inferior for hens fed the lower NPP regimens (P < 0.05). In the presence of phytase, production traits were not different for hens fed the lowest NPP regimen (0.15-0.10-0.10%) than for the unsupplemented phytase control for the entire experiment (P > 0.05). The overall effect of NPP regimens and phytase on specific gravity for the entire experiment was significant. Specific gravity was greater for hens fed the regimens with less NPP than for hens fed regimens with greater NPP, and phytase had an adverse effect on specific gravity. However, specific gravity of hens fed the lowest NPP regimen with phytase was not significantly different from the unsupplemented phytase control group. The overall effect of phytase on phytate P retention was significant during digestion trials; phytase increased phytate P retention by about 15%. Daily total P excretion was 34 to 47% less for hens fed the lowest NPP regimen with phytase than for the unsupplemented phytase control group. Significant interactions existed for a number of traits and are discussed in the text.