Microbial Phytase Research Articles

Digestibility of amino acids and concentration of metabolizable energy are greater in high-oil corn than in conventional corn when fed to growing pigs

Two experiments were conducted to test the hypothesis that the coefficient of standardized ileal digestibility (CSID) of amino acids (AA), concentrations of digestible energy (DE) and metabolizable energy (ME), and the coefficient of standardized total tract digestibility (CSTTD) of phosphorus (P) in high-oil corn is greater than in conventional corn. In experiment 1, 9 pigs (81.5 ± 5.9 kg) that had a T-cannula installed in the distal ileum were allotted to a triplicated 3 × 3 Latin square design with 3 diets and 3 periods for 9 replicates per diet. A nitrogen-free diet and 2 diets that contained conventional corn or high-oil corn as the only source of crude protein (CP) and AA were formulated. Results indicated that the CSID of CP and most AA was greater (P < 0.05) in high-oil corn than in conventional corn, which consequently resulted in greater concentrations of standardized ileal digestible AA in high-oil than in conventional corn. In experiment 2, 64 pigs (18.75 ± 2.2 kg) were housed in metabolism crates and allotted to a 2 × 4 factorial arrangement with 2 sources of corn (conventional corn or high-oil corn) and 4 levels of microbial phytase (0, 500, 1000, or 2000 phytase units/kg). Feces and urine were collected using the marker-to-marker approach with 5-day adaptation and 4-day collection periods. The digestibility of gross energy (GE) was not different between diets containing high-oil corn and diets containing conventional corn. However, because of the greater GE in high-oil corn than in conventional corn, concentrations of DE and ME in high-oil corn were greater (P < 0.01) than in conventional corn. Addition of microbial phytase to diets increased (P < 0.01) the CSTTD of P in both corn sources, and the CSTTD of P was greater (P < 0.01) in high-oil corn than in conventional corn. In conclusion, high-oil corn contained more standardized ileal digestible AA, DE, and ME than conventional corn. The CSTTD of P in high oil corn, regardless of phytase supplementation, was also greater than in conventional corn. These results indicate that high-oil corn has greater nutritional value than conventional corn when fed to pigs.

Supplementation of Diet With Microbial And Thermo-Stable 6-Phytase With Recommended And Deficient CA and P Level on Broiler Performance

An experiment was carried out to investigate the performances with 1080 male Cobb-500 broiler chicks using different levels of a microbial phytase in plantbased diet. Six dietary treatments were formulated as follows; the first 3 diets were balanced with Ca and Av. P according to the recommendation of Cobb-500 served as basal diet without phytase enzyme (T1), basal diet with 100g phytase ton-1 feed (T2) and basal diet with 200g phytase ton-1 feed (T3), while the last 3 diets were deficient in Ca and Av. P and containing no phytase enzyme (T4), diet with 100g phytase/ton feed (T5) and diet with 200g phytase ton-1 feed (T6). All 6 treatments were replicated 6 times. Body weight, feed consumption and mortality of broilers were recorded weekly. The highest body weight was found in T3 with 200g phytase ton-1 feed with recommended Ca and Av. P level in the diet, followed by T6 with 200g phytase/ton feed with deficient in Ca and Av. P level in the diet (P&lt;0.05). The lowest weight was found in T1 without phytase with recommended Ca and Av. P level in the diet. The feed consumption, feed conversion ratio and mortality of the birds during 35 days of experimental period did not differ significantly (P&lt;0.05). The meat yield characteristics at 35 days of age were non-significant among different treatments (P&gt;0.05). Significantly lower value of total ash (%), Ca (%) and total P (%) of tibia was found in control group (T1) and T4. The results of this experiment revealed that phytase supplementation at 200g ton-1 of feed improved broiler performances at either recommended or deficient level of Ca and Av. P. SAARC J. Agric., 19(1): 211-222 (2021)

Reduced concentrations of limestone and monocalcium phosphate in diets without or with microbial phytase did not influence gastric pH, fecal score, or growth performance, but reduced bone ash and serum albumin in weanling pigs.

An experiment was conducted to test the hypothesis that reducing limestone and monocalcium phosphate in diets for weanling pigs by lowering the concentration of Ca and P or by including microbial phytase in the diet will reduce stomach pH and fecal score and will improve growth performance of pigs. A total of 160 weanling pigs (5.75 ± 1.04 kg) were allotted to four corn-soybean meal-based diets in a completely randomized design with five pigs per pen. Diets for phase 1 (d 1 to 15) were formulated using a 2 × 2 factorial design with 2 concentrations of Ca and P (adequate or deficient levels of total Ca and digestible P) and 2 inclusion levels of phytase (0 or 2,000 units/kg feed). Phytase was assumed to release 0.16% total Ca and 0.11% digestible P. Common diets were fed in phases 2 (d 16 to 21) and 3 (d 22 to 35). Fecal scores were recorded in phase 1 and on d 15, gastric pH was measured and a blood sample and the right femur were collected from one pig per pen. Growth performance data were recorded within each phase. Results indicated that in phase 1, at deficient dietary Ca and P, pigs fed the diet with phytase had greater (P < 0.05) average daily gain (ADG) and gain to feed (G:F) compared with pigs fed the diet without phytase, but in diets with adequate levels of Ca and P, no effect of phytase inclusion was observed (interaction, P < 0.05). Without phytase, pigs fed the diet with deficient Ca and P had reduced (P < 0.05) G:F compared with pigs fed the diet with adequate Ca and P, but if phytase was included, there was no effect of Ca and P on G:F (interaction, P < 0.05). For phases 2 and 3, and from d 1 to 35, no differences among dietary treatments were observed for ADG or G:F. Bone ash was greater (P < 0.05) in pigs fed diets with adequate Ca and P than in pigs fed diets with deficient Ca and P, but no effect of phytase inclusion was observed on bone ash. Concentrations of Ca and P did not affect stomach pH or fecal score, but pigs fed diets with phytase tended (P < 0.10) to have reduced stomach pH and fecal score compared with pigs fed diets without phytase. Pigs fed diets with adequate Ca and P had greater (P < 0.05) albumin in serum than pigs fed the Ca- and P-deficient diets. In conclusion, phytase inclusion in phase 1 diets may reduce diarrhea, but lowering Ca and P does not reduce stomach pH or fecal score and decreases bone ash, although growth performance during the entire weanling period is not affected.

Statistical modeling and optimization of microbial phytase production towards utilization as a feed supplement

Statistical modeling and optimization of microbial phytase production towards utilization as a feed supplement

61 Effects of Reducing the Concentration of Ca and P and Increasing Microbial Phytase on Gastric Ph, Fecal Score, Growth Performance, and Bone Ash of Weanling Pigs

Abstract An experiment was conducted to test the hypothesis that lowering dietary Ca and P reduces gastric pH and diarrhea of weanling pigs, but microbial phytase overcomes negative effects of low Ca and P on growth performance and bone ash. A total of 320 weanling pigs (6.35 ± 0.87 kg) were allotted to 8 corn-soybean meal-based diets in a randomized complete block design with 5 pigs/pen. Two phase 1 (d 1 to 14) control diets contained 100 or 50% of total Ca and digestible P relative to the requirement, and 6 diets in which 500, 2,000, or 16,000 units/kg of phytase was added to each control diet were formulated. Common diets were fed in phases 2 (d 15 to 27) and 3 (d 28 to 42). Fecal scores were recorded in phase 1 and growth performance data were recorded within each phase. Gastric pH was measured in 1 pig/pen on d 14; on d 14 and 42, the right femur of 1 pig/pen was collected. Data were analyzed using contrast statements in SAS. Results indicated that during phase 1, lowering Ca and P did not reduce gastric pH or fecal score, but the 50%-diets reduced (P &amp;lt; 0.05) average daily gain and average daily feed intake of pigs compared with the 100%-diets (Table 1). Phytase above 500 units/kg increased (P &amp;lt; 0.05) gain:feed ratio and tended (P &amp;lt; 0.10) to decrease gastric pH. Pigs fed the 50%-diets had reduced (P &amp;lt; 0.05) bone ash at d 14 and 42 compared with pigs fed the 100%-diets regardless of phytase inclusion level. In conclusion, reducing Ca and P in diets for weanling pigs does not decrease gastric pH or fecal score, but compromises growth performance and bone mineralization. However, super-dosing of phytase increases G:F of pigs regardless of dietary Ca and P concentration.

Supplementation of Microbial and Fungal Phytases to Low Protein and Energy Diets: Effects on Productive Performance, Nutrient Digestibility, and Blood Profiles of Broilers

To evaluate in possible use of phytases for improving the utilization of low protein and energy diets, 420, one-day-old chicks were distributed among 7 groups (5 replicates of 12 chicks/group). During the starter (1–35 day), grower (37–56 day), and finisher (57–64 day) periods, the control group fed diets containing 21.2% crude protein (CP)-2947 Kcal/kg metabolizable energy (ME), 19.6 CP-3023 ME and 18.0 CP-3100 ME, respectively. The three low-CP groups received diets isocaloric but with −1% CP than the control, while the three low-CPME groups fed diets with −1% CP and −100 Kcal than the control. In addition, the low-CP and low-CPME groups were supplemented with 0 (low-CP_uns and low-CPME_uns), 500 U/kg of an Aspergillus niger (low-CP_AP and low-CPME_AP) or 500 FTU/kg of an Escherichia coli phytase (low-CP_EP and low-CPME_EP), respectively. Low-CP and low-CPME diets decreased (p &lt; 0.01) the intake of feed as well as the protein and metabolizable energy conversion ratios in comparison to the control group. In general, phytases lowered (p &lt; 0.01) the intake of feed, protein, and energy, but bacterial phytase showed a higher (p &lt; 0.01) effect than A. niger one. The diets with low-CP and low-CPME levels decreased (p &lt; 0.01) the amount of the excreta nitrogen. The supplementation of phytases had similar effects on digestibility of nutrients, carcass traits, bone mineralization and blood biochemistry. The supplementation of A. niger increased abdominal fat deposition of compared low-CPME diet compared to low-CPME_uns diet. All diets showed similar production index allowing the use of low-CPME diet when phytases was supplemented.

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.

True phosphorus digestibility of cottonseed meal and rice husk supplemented with microbial phytase in broiler chickens

This research aimed to determine effects of phytase in cottonseed meal (CM) and rice husk (RH) based diets on true phosphorus digestibility (TPD) by broiler chickens. Two studies were conducted with 576 one-day-old broiler chickens using regression analysis to determine the TPD in these diets and the response to phytase supplementation. Six semi-purified diets were formulated to contain 150 g, 300 g, and 450 g each of CM/kg (experiment 1) and RH/kg (experiment 2) with phytase supplied at 0 and 1000 units/kg. Titanium dioxide was added to the diets at the rate of 5 g/kg as an indigestible maker. A total of 288 broiler chickens in each study were weighed and allotted to the six diets with six replicates of eight birds in a randomized complete block design. The birds were fed the experimental diets until day 26 post hatch. The coefficients of true phosphorus retention (TPR) were 0.8 for CM and 0.78 for RH without phytase; 0.93 for CM and 0.92 for RH with phytase. True phosphorus digestibility was 0.82 for CM and 0.75 for RH without phytase; and 0.95 for CM and 0.92 for RH with phytase. Phytase supplementation resulted in 13.27 and 17.94 % increases in TPD; and 12.29 and 13.61 % increases in TPR by birds fed the CM and RH diets, respectively. Phytase supplementation of CM and RH based diets increased TPD and improved total TPR and true ileal phosphorus digestibility in broiler chickens.

Preliminary screening, isolation and identification of microbial phytase producers from soil

Preliminary screening, isolation and identification of microbial phytase producers from soil

Effect of two phytases at two doses on performance and phytate degradation in broilers during 1-21 days of age.

The effect of two microbial phytases at two dose-levels on performance and apparent ileal digestibility (AID) of nutrients in broilers fed European-type diets was studied. A total of 1,200 d-old Ross 308 male broilers were randomly assigned to 5 treatments with 30 birds/pen and 8 pens/treatment. A nutritionally adequate positive control (PC) diet was tested against 4 experimental diets containing reduced total P, retainable P, Ca and Na as per the recommended nutritional contribution for Buttiauxella phytase (Phy B) at 1,000 FTU/kg (-1.87 g/kg, -1.59 g/kg, -1.99 g/kg and -0.4 g/kg vs. PC, respectively). Experimental diets were supplemented with Phy B at 500 FTU/kg or 1,000 FTU/kg, or Citrobacter phytase (Phy C) at 1,000 FTU/kg or 2,000 FTU/kg. Diets were based on corn, soybean meal, rapeseed meal and sunflower meal and formulated by phase (starter 1–10 d, grower 11–21 d) in crumbled or pelleted form. Overall (d 1–21), at 1,000 FTU/kg, birds fed Phy C exhibited lower BWG (-2.7%), FI (-3.4%) and tibia ash (-2.2%) vs. PC (P < 0.05), and reduced BWG (-3.6%), FI (-3.9%) and tibia ash (-1.8%) vs. Phy B (P < 0.05). Phy B at 1,000 FTU/kg and Phy C at 2,000 FTU/kg maintained performance equivalent to the PC. Digestibility of Ca did not differ among phytase treatments but at 1,000 FTU/kg AID P was greater with Phy B than Phy C (72.3% vs. 62.7%, P < 0.05). Ileal phytate (myo-inositol hexakisphosphate, IP6) digestibility was greatest with Phy B at 1,000 FTU/kg which was higher than Phy C at 1,000 FTU/kg (87.6 vs. 60.6%, P < 0.05). The findings indicate a higher phytate degradation rate of Phy B than Phy C at equivalent dose-level and this is correlated to the performance of the broilers.

Expression of Pantoea sp. 3.5.1 AgpP Phytase in Three Expression Systems

Nowadays, microbial phytases have been widely used as feed additives that increase the bioavailability of phosphorus for monogastric animals. Still, there is an active search for new phytases, development of effective production systems, and study of their properties. In this study, we compared the biochemical characteristics of bacterial histidine acid phytase of Pantoea sp. 3.5.1 produced in three different expression systems: Escherichia coli, methylotrophic yeast Pichia pastoris, and yeast Yarrowia lipolytica. The maximum activity of the recombinant phytase AgpP-P expressed by P. pastoris occurred at pH 4.0, while the pH optimum of the recombinant AgpP-Y phytase expressed by Y. lipolytica is shifted towards more acidic pH 3.0. The recombinant AgpP-P enzyme is stable at pH values ​​from 2.0 to 5.0, while the AgpP-Y remains active at pH values ​​from 3.0 to 7.0; however, at pH above 8.0, the enzyme becomes inactive. The temperature optimum of recombinant AgpP-P phytase corresponded to 50 °С, while the temperature optimum for AgpP-Y was at 45 °С. The recombinant enzymes AgpP-P and AgpP-Y retained activity at temperatures from 4 to 70 °C and from 4 to 60 °C, respectively. Bivalent metal ions at a concentration of 1 mM had the same effect on the activity of recombinant phytases from E. coli, P. pastoris, and Y. lipolytica: Ca2 +, Mg2 +, and Mn2 + ions more than doubled the activity of enzymes, while Co2 + did not affect the activity of phytases, while ions Zn2 +, Cu2 +, and Fe2 + inhibited the activity of enzymes.

Adaptation of Gut Microbiome to Transgenic Pigs Secreting β-Glucanase, Xylanase, and Phytase.

We previously generated transgenic pigs with enhanced growth rate and reduced nutrient loss. However, the composition of their gut microbiome is unknown. In this study, we successfully generated EGFP marker-free transgenic (MF-TG) pigs with high expression levels of microbial β-glucanase, xylanase, and phytase in the parotid gland. We collected intestinal contents from the ileum, cecum and colon of five MF-TG and five wild-type (WT) sows and investigated the gut microbiome of the transgenic pigs via metagenomic analysis. Results showed that the levels of probiotics, such as Lactobacillus reuteri and Streptococcus, were more abundant in the cecum of the MF-TG pigs and higher than those of WT pigs. By contrast, the levels of harmful microorganisms, such as Campylobacter, Chlamydia trachomatis, and Campylobacter fetus, and various unidentified viruses, were higher in the cecum of the WT pigs than those of the MF-TG pigs. By comparing unigenes and the eggNOG database, we found that the microorganisms in the colon of the MF-TG pigs had high fractional abundance in DNA (cytosine-5)-methyltransferase 1 and serine-type D-Ala-D-Ala carboxypeptidase, whereas the aspartate carbamoyltransferase regulatory subunit and outer membrane protein pathways were enriched in the WT pigs. Moreover, the microorganisms in the cecum of the MF-TG pigs were active in GlycosylTransferase Family 8 (GT8), Glycoside Hydrolase Family 13 (GH13), and Glycoside Hydrolase Family 32 (GH32). Furthermore, the levels of numerous carbohydrases, such as glucan 1,3-beta-glucosidase, xylan 1,4-beta-xylosidase and exo-1,3-1,4-glucanase, were higher in the cecum of the MF-TG pigs than those of the WT pigs. The results indicated that intestinal microbes can change adaptively to the secretion of transgenic enzymes, thereby forming a benign cooperation with their host. This cooperation could be beneficial for improving feed efficiency.

Formulating diets based on digestible calcium instead of total calcium does not affect growth performance or carcass characteristics, but microbial phytase ameliorates bone resorption caused by low calcium in diets fed to pigs from 11 to 130 kg.

An experiment was conducted to test the hypothesis that the requirement for Ca expressed as a ratio between standardized total tract digestible (STTD) Ca and STTD P obtained in short-term experiments may be applied to pigs fed diets without or with microbial phytase from 11 to 130 kg. In a 5-phase program, 160 pigs (body weight: 11.2 ± 1.8 kg) were randomly allotted to 32 pens and 4 corn-soybean meal-based diets in a 2 × 2 factorial design with 2 diet formulation principles (total Ca or STTD Ca), and 2 phytase inclusion levels (0 or 500 units/kg of feed) assuming phytase released 0.11% STTD P and 0.16% total Ca. The STTD Ca:STTD P ratios were 1.40:1, 1.35:1, 1.25:1, 1.18:1, and 1.10:1 for phases 1 to 5, and STTD P was at the requirement. Weights of pigs and feed left in feeders were recorded at the end of each phase. At the conclusion of phase 1 (day 24), 1 pig per pen was euthanized and a blood sample and the right femur were collected. At the end of phases 2 to 5, a blood sample was collected from the same pig in each pen. At the conclusion of the experiment (day 126), the right femur of 1 pig per pen was collected and carcass characteristics from this pig were measured. No interactions were observed between diet formulation principle and phytase inclusion for growth performance in any phase and no differences among treatments were observed for overall growth performance. Plasma Ca and P and bone ash at the end of phase 1 were also not influenced by dietary treatments. However, on day 126, pigs fed nonphytase diets formulated based on total Ca had greater bone ash than pigs fed STTD Ca-based diets, but if phytase was used, no differences were observed between the 2 formulation principles (interaction P < 0.05). At the end of phases 2 and 3, pigs fed diets without phytase had greater (P < 0.05) plasma P than pigs fed diets with phytase, but no differences were observed at the end of phases 4 and 5. A negative quadratic effect (P < 0.05) of phase (2 to 5) on the concentration of plasma Ca was observed, whereas plasma P increased (quadratic; P < 0.05) from phases 2 to 5. However, there was no interaction or effect of diet formulation principle or phytase inclusion on any carcass characteristics measured. In conclusion, STTD Ca to STTD P ratios can be used in diet formulation for growing-finishing pigs without affecting growth performance or carcass characteristics and phytase inclusion ameliorates bone resorption caused by low dietary Ca and P.

Effect of Bacterial or Fungal Phytase Supplementation on the Performance, Egg Quality, Plasma Biochemical Parameters, and Reproductive Morphology of Laying Hens.

Simple SummaryThe present study shows that 5000 FTU/kg dietary supplementation with bacterial (E. coli) or fungal (Aspergillus niger and Trichodermareesei) sources of phytase with less available phosphorus is capable of maintaining productive efficiency, reproductive morphology, and egg quality of laying hens. Eggshell consistency was increased while yolk cholesterol was decreased as a result of diets supplemented with bacterial or fungal phytase. All in all, our results clarify that feeding laying hens bacterial and fungal phytase at 5000 FTU/kg can be effective to replace inorganic phosphorus commercially.Catalytic and physicochemical properties of microbial phytase sources may differ, affecting phosphorus (P) release and subsequently the productive and reproductive performance of layers. The current study aimed to evaluate the impact of bacterial and fungal phytase sources on layer productivity, egg production, biochemical blood indices, and reproductive morphology. For this purpose, 360 Bovans brown hens at 42 weeks of age were randomly allocated into 4 experimental groups, each with 15 replicates of 6 hens. The first group (control) was fed a basal diet with 4.6 g/kg available P. In contrast, the second, third, and fourth groups were fed diets treated with 3.2 g/kg available P, supplemented with either 5000 FTU/kg of bacterial E. coli (QuantumTM Blue 5G), fungal Aspergillus niger (VemoZyme® F 5000 Naturally Thermostable Phytase (NTP)), or fungal Trichodermareesei (Yemzim® FZ100). Dietary supplementation of bacterial and fungal phytases did not affect the productive performance or egg quality criteria, except for increased shell weight and thickness (p < 0.05). Serum hepatic function biomarkers and lipid profiles were not altered in treated hens, while calcium and P levels were increased (p < 0.05) related to the controls. Ovary index and length, and relative weight of oviduct and its segments were not influenced. The contents of cholesterol and malondialdehyde in the yolks from treated birds were lower compared to control hens, while calcium and P content increased (p < 0.05). Conclusively, bacterial and fungal phytase sources can compensate for the reduction of available P in layers’ diets and enhance shell and yolk quality without affecting productive performance, and no differences among them were noticed.

Response of Broiler Chicken to Microbial Phytase: Effects on Phytin-Phosphorus, Serum Biochemistry and Carcass Characteristics

Response of Broiler Chicken to Microbial Phytase: Effects on Phytin-Phosphorus, Serum Biochemistry and Carcass Characteristics

Measurement of total tract retention of phosphorus in several feedstuffs of plant origin for broiler chickens: effect of microbial phytase

An experiment was conducted to compare the true total tract retention of phosphorus (P) in soybean meal, canola meal, cottonseeds meal, peanut meal, corn distiller’s dried grains with soluble (DDGS), wheat bran, wheat grain, and wheat shorts with or without phytase addition. A total of 576 male Arbour Acres broilers aged 23 days of similar live weight were randomly assigned into 16 treatments with 6 replicates each and 6 birds in each replicate. Sixteen diets were designed by combining 2 factors that include 8 ingredients and phytase level (0 or 1000 FTU/kg). Dietary P was only provided by the ingredient to be tested. A purified P-free diet was prepared to determine endogenous P loss (EPL). The retainability of P was evaluated by collecting an excreta trial. The results showed that basal EPL was 97.45 mg/DMI. The true retainability of P in soybean meal, canola meal, cottonseed meal, and DDGS was 53.90%, 53.22%, 54.73%, and 49.45%, respectively, much higher than peanut meal (42.76%), wheat bran (38.26%), wheat grain (36.77%), and wheat shorts (36.95%). Phytase significantly increased apparent or true retainability of P (p < .05). Phytase showed the greatest improvement of retainability of P for wheat ingredients (wheat shorts 41.35%; wheat grain 41.34%; wheat bran 35.94%) and soybean meal (31.52%), followed by canola meal (23.07%), cottonseed meal (14.43%), peanut meal (11.51%), and DDGS (10.23%). The retainable P equivalent of 1000 FTUs of microbial phytase corresponding to ingredients was between 0.4 g (DDGS and peanut meal) and 1.3 g (wheat bran). HIGHLIGHTS Phytase significantly increased apparent or true retainability of P in feed ingredients of plant origin. Phytase showed the greatest improvement of retainability of P for wheat ingredients, more than 30%. The retainable P equivalent of 1000 FTUs of microbial phytase corresponding to different ingredients was between 0.4 and 1.3 g.

EFFECT OF PHYTASE ENZYME AND CITRIC ACID ON PRODUCTIVE PERFORMANCE, NUTRIENT RETENTION AND TIBIA BONE OF BROILER CHICKS FED LOW AVAILABLE PHOSPHORUS DIET

The study investigate the effect of feeding low available phosphorus (AP) diet supplemented with three levels of microbial phytase (MP) and /or three levels of citric acid (CA) on broiler performance, tibia bone and nutrient retention. Four hundred day- old Ross broiler chicks were randomly allocated into ten treated groups, with four replicates of 10 birds each. The chicks were fed ten different diets as normal phosphorus 0.45% AP (positive control, PC) and nine groups with phosphorus deficient diets 0.25% AP (negative control, NC) supplemented with three CA levels as 0%, 1% or 2% and / or MP levels 0, 500 and 1000 FTU/Kg. The results indicated that supplementation of MP and /or CA into NC diet significantly improved body gain of chicks. Feed intake significantly increased due to adding 1% CA and MP levels into NC diet. Feed conversion ratio improved due to supplementing MP or CA into NC diet. There is no significant effect on tibia width and breaking strength by adding MP and/or CA into NC diet. Adding MP into NC diet significantly improved tibia length, weight, and ash content while, citric acid affected significantly at the first stage of growth only. Blood phosphorus increased significantly by supplementing MP into NC diet at the 5th week of age, while blood calcium was not affected significantly by MP and/or CA. Tibia calcium of chicks fed NC diet was higher than those fed PC diet or NC diet enriched with MP and/or CA. Tibia phosphorus did not response clearly for adding MP or CA into NC diet. Nitrogen and calcium retention of chicks fed NC were significantly lower than those fed PC or NC diet supplemented with 1000 FTU/kg MP and CA. Phosphorus retention of chicks fed NC diet was significantly similar for those fed PC or NC diets supplemented with MP and/or CA. It can be concluded that adding MP at 500 FTU/kg level with 1% CA into NC diet was effectiveness to improve body weight gain and tibia bone characteristics as like as those fed PC or NC diet enriched with 1000 FTU/kg MP.

In Vitro Characterization of a Novel Consensus Bacterial 6-Phytase and One of its Variants

Background:: Microbial phytases are added to animal feed to hydrolyze phytic acid (myoinositol hexakisphosphate, IP6) and phytate (salt of phytic acid) increasing phosphorus bioavailability. Novel phytases with enhanced bio-efficacy are being developed. Objective:: To characterize the biochemical and enzymatic properties of a novel consensus bacterial 6- phytase and its variant (PhyG), produced in Trichoderma reesei. Methods:: The in vitro specific activity, kinetic parameters, pH-activity profiles (relative to pH5.5), IP6 degradation, hydrolysis products and phosphate release of the phytases were determined using sodium phytate substrate. Melting point (Tm) was determined by differential scanning calorimetry and thermostability assessed by measuring residual activity at different temperatures. In vivo effects of PhyG supplementation at 0 to 1,000 FTU/kg on ileal IP6 digestibility and IP ester concentrations were determined in piglets. Results:: Both phytases exhibited pH optima of 3.5-4.5, high relative activity over a wide pH range (pH2.0-5.0), and substantial relative activity at pH1.5. At pH3.0, the specific activity of the PhyG variant was 1487 U/mg protein and at pH3.5 the kinetic constants were 240 μM (Km) and 1873 s-1 (Kcat). The hydrolysis of IP6 by both phytases was rapid. The major initial hydrolysis product was DLI( 1,2,3,4,5)P5, designating the phytases as bacterial 6-phytases (EC 3.1.3.26). Hydrolysis occurred at the D-3 (L-1) position in ~30% of instances, indicating a dual-specificity. Conclusion: Both phytases showed high thermostability compared to wild type and existing commercial bacterial 6-phytases; PhyG exhibited 95% residual activity after 20 min incubation at 85.4ºC (pH5.5), Tm50 of ~93.2ºC and Tm of 98.8ºC. In vivo, PhyG at 1,000 FTU/kg achieved an ileal digestibility of IP6 of 89.3%.

Performance, blood profile and microbial characteristics of broiler chicken fed phytase supplemented diets

Phytate is an anti-nutritional factor found in grains which limits the availability of essential minerals in monogastric nutrition as they lack enzymes to break it down. Its effect on performance, nutrient retention and availability of many nutrients including the macro elements and trace minerals have been documented in many studies in different animal species with conflicting results. Thus, this study was conducted to evaluate the performance, blood metabolites and microbial population in broiler chicks fed graded levels of phytase enzyme at 0, 250, 500, 750 and 1000FTU/kg of the experimental diet in a 56-day feeding trial. One hundred and ninety-five, one-day-old Arbor acre chicks were randomly allotted into five dietary treatments in a completely randomized design and the treatment had three replicates with 13 birds each. Data were collected on performance characteristics weekly while on day 56, blood was collected at the jugular vein of two birds per replicate for haematological and serum biochemical parameters. Consequently, two birds per replicate were also sacrificed and excised for jejunum and ileum microflora assay. Result for the performance characteristics showed no significant (P&gt;0.05) differences in final bodyweight, daily weight gain, feed intake and feed conversion ratio. Initial body weight ranged from 36.08±0.78-40.13±3.57g/bird, final body weight ranged from 2192.86±28.87- 2466.81±117.40g/bird and the Feed conversion ratio also ranged from 2.78-3.21. Also, there were no significant (P&gt;0.05) differences observed in the haematological and serum biochemical parameters but numerical differences exist. Packed cell volume had values between 21.33-26.00% while haemoglobin also had values ranging from 7.11-8.67g/100mL. However, significant (P&lt;0.05) differences exist in the ileum while no significant (P&gt;0.05) differences were found in jejunum tissues. For Aspergillus flavus, 59.4±5.1cfu/mL was significantly (p&lt;0.05) higher than 8.4±3.0cfu/mL for the ileum tissue while the jejunum tissue had values ranging from 4.2±1.80-16.8±6.00mL which were not significantly (P&gt;0.05) different. In addition, significant (p&lt;0.05) differences were observed for the ileum and jejunum tissue for Escherichia coli. The ileum tissue had significant values that ranged from 3.3±0.9-24.6±4.8mL while the jejunum also had significant values that ranged from 4.5±0.3-27.9±5.7mL. In conclusion, the use of microbial phytase had no influence on the performance of broilers and blood metabolite but has effect on the microflora of broiler chicken.

A novel consensus bacterial 6-phytase variant completely replaced inorganic phosphate in broiler diets, maintaining growth performance and bone quality: data from two independent trials

Total replacement of dietary inorganic phosphate (Pi) by a novel consensus bacterial 6-phytase variant (PhyG) in phytate-rich diets (>0.3% phytate-P) was investigated in 2 trials using growth performance and bone quality as outcome measures. Both trials utilized a completely randomized design with 5 dietary treatments across 4 phases: starter (0–10 d), grower (10–21 d), finisher 1 (21–35 d), and finisher 2 (35–42 d). Treatments comprised a nutritionally adequate positive control (PC) diet containing monocalcium phosphate and 4 experimental diets (IPF1, IPF2, IPF3, and IPF4), all containing no added Pi and reduced in Ca by 0.2 to 0.3% units vs. PC. IPF1contained PhyG at 1,000 FTU/kg (all phases); IPF2 contained PhyG at 1,000 FTU/kg (all phases) and was additionally reduced in digestible AA, ME, and sodium (−0.2 to −0.4% points, −74 kcal/kg, –0.04% points, respectively, vs. PC); IPF3 contained PhyG at 3,000 FTU/kg in starter, 2,000 FTU/kg in grower, and 1,000 FTU/kg in finisher phases; and IPF4 contained xylanase (2,000 U/kg) and PhyG (2,000 FTU/kg in starter, 1,500 FTU/kg in grower, and 1,000 FTU/kg in finisher phases) and was additionally reduced in ME (–71 kcal/kg vs. PC). Ross 308 broilers were used (trial 1: n = 1,200 mixed sex; 24 birds per pen × 10 replicates; trial 2: n = 1,300 males; 26 birds × 10 replicates). During all phases in both trials, all IPF treatments maintained or improved BW, ADG, ADFI, FCR and BW-corrected FCRc and bone quality parameters vs. PC. vs. PC, treatment IPF3 increased ADG during starter phase (+10.8%) and reduced overall FCRc (−12 points, P < 0.05) in Trial 1, and increased overall ADG (+4.4%), day 35 and day 42 BW (+3.5%, +4.9%), and reduced overall FCRc (−11 points) in Trial 2 (P < 0.05). IPF4 produced equivalent performance to IPF3 (both trials). These are the first data to demonstrate total replacement of Pi by microbial phytase during an entire growth cycle in broiler diets.