Phytase For Broilers Research Articles

Long story from past to present: calcium, phosphorus, and phytase

Abstract Calcium (Ca) and phosphorus (P), two main elements, have vital physiological and metabolic roles in animal bodies. Accurate comprehension of the interaction of these two elements and their value in various resources helps to obtain their optimal formulation in poultry diets. Hence, in previous studies, the hormonal axes controlling Ca and P homeostasis have been primarily investigated. However, to estimate Ca and P requirements in modern broiler chickens, in addition to growth performance, other parameters such as Ca and P digestibility, bone strength, and excretion into the environment should also be considered. Since a large amount of P in poultry feed ingredients is bound to phytate, phytases are added to poultry diets to release the P from phytate. However, many nutritionists need clarification on what dose of dietary phytase is required to release the maximum phytate P and how phytase activity will be optimized. Therefore, the present review study has attempted to explore the factors that affect the digestibility of different resources of Ca and P. In addition, the effect of excess dietary Ca on phytase activity and studies related to super dosing of phytase in broilers are provided. Finally, the values of phytate P in standard poultry feed ingredients and the latest update of the studies on determining Ca and P requirements are summarized.

Renal expression of Ca and P transporters: contrasting responses to dietary Ca and microbial phytase in broilers and growing pigs.

Enhanced dietary Ca intake linearly increases intestinal Ca absorption in pigs, but not in broilers, suggesting potential differences in whole body Ca homeostasis. To determine the role of kidney in Ca homeostasis in these species, we varied in growing pigs in experiment (Exp) 1, the dietary Ca content 2.0 vs. 9.6 g/kg and phytase 0 vs. 500 FTU/kg, in broilers, in Exp 2 the dietary Ca/retainable P from 1.3 to 2.8 and phytase 0 vs. 1000 FTU/kg, and in Exp 3 dietary Ca/P from 0.50 to 1.75. Increasing dietary Ca reduced renal mRNA expression of Ca-related transporters (TRPV5, TRPV6, CaBP-D28k, NCX1) and tight junctions (CLDN-12 and -16) in pigs, indicating Ca reabsorption was reduced to maintain Ca homeostasis. In broilers (Exp 2), high dietary Ca increased renal TRPV6, CaBP-D28k and CLDN-2 mRNA, indicating an increased capacity for Ca reabsorption. Moreover, the effect of dietary Ca was enhanced by inclusion of dietary phytase in pigs but reduced in broilers. Furthermore, increasing dietary Ca upregulated PiT-1 while phytase downregulated XPR1 mRNA expression in pigs; in broilers dietary Ca downregulated renal mRNA expression of NaPi-IIa, PiT-1, PiT-2 and XPR1, while phytase downregulated NaPi-IIa but upregulated PiT-2 and XPR1 mRNA expression. In Exp 3, Ca/P effect on transporter mRNA expression was largely consistent with Exp 2. In conclusion of this study, together with previously measured data about Ca and P homeostasis, in pigs the kidneys play a more regulatory role in Ca homeostasis than in broilers where the intestine is more important for regulation.

Approaches to determine the efficiency of novel 3-phytase from Klebsiella pneumoniae and commercial phytase in broilers from 1 to 14 d of age

This study aimed to evaluate the effects of a laboratory 3-phytase (the expression of the phyK gene, Lab-Phy) and a commercial 6-phytase (Quantum Blue 40 P, Com-Phy) alone and in combination (corn-soy-based diets) in broilers. A total of 400, day-old Ross 308 male broilers were randomly assigned to 5 treatments with 10 replicate cages (8 chicks/cage) for a 14-day trial. Experimental treatments included the positive control (0.95% Ca and 0.48% nonphytate phosphorus (nPP), PC), negative control (0.90% Ca and 0.22% nPP, NC), and NC which was supplemented with Lab-Phy 250 FTY/kg and Com-Phy 250 FTY/kg alone or in combination of Lab-Phy 125 FTY/kg and Com-Phy 125 FTY/kg. The inclusion of Lab-Phy in the NC diet significantly improved the P and Ca content in the tibia compared to the NC group. Moreover, the inclusion of Com-Phy alone and in combination with Lab-Phy in the NC diet significantly increased the P and Ca content in the tibia compared to the Lab-Phy. The mRNA expression of NaPi-IIb was upregulated in the duodenum by the reduction of nPP and downregulated by the inclusion of any phytase, whereas other nutrient transporters were not influenced by the reduction of nPP or the addition of phytase in the small intestine mucosa. Broilers receiving the NC diet obtained the lowest body weight (BW) and body weight gain (BWG) at 8 to 14 and 1 to 14 d of age. The NC group showed the lowest villi height and surface area, Newcastle disease (ND) antibody titer, and digestibility of nutrients compared to the PC group at 14 d of age. Supplementing the NC diet with the Lab-Phy and Com-Phy individually, or in combination tended to improve BW, BWG, tibia characteristics, villi characteristics, ND, and retained CP and P, and apparent ileal digestibility of CP, P, methionine, and threonine. The present research indicated that the studied traits by the combination of phytases were slightly better than the average of the 2 individually, suggesting there might be some value in combining the laboratory and commercial phytases.

Use of Zn concentration in the gastrointestinal tract as a measure of phytate susceptibility to the effect of phytase supplementation in broilers

Zinc (Zn) is the most vulnerable cation to complexation with phytate. An experiment was conducted to evaluate the potential of measurements of Zn concentration in the gastrointestinal tract as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers. Ross 308 broilers (n = 180) were fed one of 5 experimental diets with differing phytase activity levels, analyzed at 605, 1150, 1804, 3954, and 5925 U/kg. Broiler performance and Zn concentration, pH, and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum were analyzed at d 21 post hatch. Phytate susceptibility to phytase degradation was determined in vivo and in vitro by measuring total phytate-P hydrolyzed in the tract or in conditions that mimicked the tract, respectively. Phytase activity level had a significant (P < 0.05) impact on Zn concentration and phytate hydrolyzed in the gizzard and ileum, but not in the duodenum. Strong relationships were observed between the amount of phytate hydrolyzed and Zn concentration in the gizzard in birds fed the diets with 1804 U/kg or higher levels of phytase. Phytate and phytase effects could therefore potentially be evaluated by measuring Zn concentration in the gizzard. Susceptible phytate levels measured in vivo and in vitro were almost identical in the diet with phytase activity of 5925 U/kg, but in the diets with lower phytase activity levels the in vitro assay overestimated the amount of P released. There were strong relationships between in vivo susceptible phytate level and pH and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum and Zn concentration in the gizzard and ileum. This illustrates that phytate susceptibility directly effects mineral availability in the gastrointestinal tract. Measurements of Zn concentration in the gastrointestinal tract, particularly in the gizzard, can potentially be used as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers.

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.

Effect of formaldehyde inclusion on phytase efficiency in broilers

SUMMARY Phytase and formaldehyde-based additives (FBA) are routinely used in broiler nutrition. Phytases hydrolyze phytate, the storage form of P in plants, making organic sources of P more digestible by poultry; FBA are also used to decrease the incidence of Salmonella contamination in feeds. Though phytase activity recovered in the feed is the most common way to measure dietary phytase inclusion, FBA reduce the analyzed phytase activity in the feed. The objective of this trial was to evaluate the effect of a FBA on the efficiency of phytase in broilers. One-day-old chicks (n = 630) were allocated to 14 treatments in a 7 × 2 factorial arrangement of treatments consisting of a positive control formulated to meet nutrient requirements or a negative control with reduced available phosphorus and calcium. The negative control diet was supplemented with 5 different phytases according to supplier recommendations (enhanced Escherichia coli Quantum phytase at 500 U/kg; wild-type E. coli Finase EC at 500 U/kg; fungal Finase P at 500 U/kg; coated fungal Ronozyme NP at 1,500 U/kg; and a coated wild-type E.coli Phyzyme TPT at 500 U/kg) with or without inclusion of an FBA (Salmex, 3 kg/t) with 5 replicates per treatment and 9 birds per replicate. At d 20, animal performance was determined by feed intake and BW gain and mortality-corrected feed conversion was calculated. All birds were euthanized and left tibias were collected and weighed for ash and determination of Ca and P. Analyzed phytase activity of the feeds containing an enhanced E. coli and a wild-type E. coli were reduced with FBA inclusion. Body weight gain and tibia weight, ash, ash concentration, ash Ca and P, and P concentration were reduced when animals were fed a low-available P diet. Phytase supplementation improved all these response variables, regardless of FBA inclusion. In conclusion, FBA inclusion may negatively affect phytase activity recovered in the feed but has no effect on phytase effectiveness in vivo.

Energy and protein levels in diets containing phytase for broilers from 22 to 42 days of age: performance and nutrient excretion

This study was conducted in order to evaluate the influence of different levels of metabolizable energy and crude protein in diets formulated according to the ideal protein concept with phytase supplementation on performance and nutrient excretion of broilers from 22 to 42 days age. It was used 1,500 Coob lineage broilers at 22 days of age and with initial weight of 833 ± 7g, distributed in completely randomized design in a 3 × 3 + 1 factorial scheme composed of three levels of correct apparent metabolizable energy (2,950; 3,100 and 3,250 kcal/kg), three levels of crude protein (14, 16 and 18%) and a control treatment, totaling ten treatments with six repetitions of 25 birds each. All diets, with the exception of the control, were supplemented with phytase. For determination of excretion of pollutants, it was used 180 broilers from the same lineage at 35 days of age,placed in metabolic cages, with ten treatments each one with six repetitions and three birds per experimental unit. The protein and energy levels in diets containing phytase influenced feed intake, weight gain, feed conversion and excretion of nitrogen, phosphorus, calcium, potassium, copper and zinc by the birds. The corrected apparent metabolizable energy level in the diets for broilers in the studied period must be increased up to 3,250 kcal/kg of metabolizable energy and the levels of crude protein, calcium and phosphorus must be reduced down to 18, 0.70 and 0.31%, respectively, provided that supplemented with amino acids and phytase to improve the performance and to reduce excretion of pollutants by birds.

The Effect of Calcium Carbonate Particle Size and Solubility on the Utilization of Phosphorus from Phytase for Broilers

A twenty-eight day floor pen experiment was carried out using 1680 Cobb-500 male day old chicks to evaluate the impact of feeding different particle sizes of calcium carbonate (CaCO ) on broiler performance 3 and tibia ash. The experiment consisted of 8 treatments with 6 replications per treatment to test 8 different CaCO particle sizes. The corn-soybean meal based diets contained 21.5% CP, 3025 kcal ME kg , 0.78% 3 1 Ca, 0.20% Non-phytate P (NPP) with 500 FTU kg of Danisco Phyzyme XP added. The average particle sizes 1 of CaCO (along with % solubility) tested were 28 (74.4), 137 (56.4), 299 (47.0), 388 (53.0), 519 (46.7), 760 3 (45.3), 796 (42.2) and 1306 (43.4) µm. Significantly (p 70.0%) limits PP hydrolysis to provide available P for growth and bone 3

Efficacy of an Escherichia coli Phytase in Broilers Fed Adequate or Reduced Phosphorus Diets and Its Effect on Carcass Characteristics

Five experiments (EXP) were conducted to assess the efficacy of an Escherichia coli phytase compared with 2 commercially available fungal phytases. In EXP 1 and 2, male broiler chicks were fed experimental diets that included a P-deficient control (0.13% available P; 0.88% Ca) alone or with graded levels of KH(2)PO(4) (0, 0.05, 0.10, or 0.15%) or phytase at levels of 250, 500, 1,000, 2,000, or 4,000 phytase units/kg of E. coli phytase (EXP 1 and 2), fungal phytase 1 (EXP 2), or fungal phytase 2 (EXP 2). In EXP 1 and 2, weight gain and tibia ash (mg/chick and %) responded linearly (P < 0.05) to inorganic P addition. In EXP 2, each level of E. coli phytase released more P than either fungal phytases 1 or 2, whether based on tibia ash weight (mg/chick) or percentage. In EXP 3, 4, and 5, dietary treatments containing adequate or deficient levels of P were fed with or without supplemental E. coli phytase. In EXP 3, weight gain and tibia ash were reduced (P < 0.05) by P deficiency, but gain and tibia ash of chicks fed E. coli phytase (250, 500, or 1,000 phytase units/kg) did not differ (P > 0.05) from that of chicks fed the P-adequate diet. In addition, carcass yield of broilers fed E. coli phytase was not reduced (P > 0.05). In EXP 4, E. coli phytase effectively supported weight gain, tibia ash, breast yield, and leg yield compared with birds fed the P-adequate diet, but clavicle breakage during processing was increased in birds fed E. coli phytase. In EXP 5, E. coli phytase again effectively supported weight gain, and no differences (P > 0.05; compared with the P-adequate diet) were noted for clavicle ash, diameter, or breaking strength. No differences (P > 0.05) in bone breakage during processing were noted among treatments. These results indicate that the addition of E. coli phytase to P-deficient broiler diets improves growth, bone, and carcass performance and is more effective at releasing phytate-bound P than the other phytase products that were tested.

Evaluation of the Nutrient Matrix Values for Phytase in Broilers

Microbial phytase has been shown to increase the availability of Ca, P, ME, and amino acids (AA) in diets for broilers. However, much more research has been conducted on the Ca and P effects than on the ME and AA effects. Therefore, 2 experiments were conducted to evaluate the effect of phytase on the release of ME and AA from corn-soybean meal diets for broilers. Experiment 1 was a battery study that lasted for 14 d and included diets adequate in all nutrients, diets deficient in ME and AA, and these later 2 diets with and without added phytase. Experiment 2 was a floorpen study that lasted 42 d and included diets with reduced levels of ME and AA with added phytase. Growth performance, meat quality, and tibia ash were not affected by using the ME and AA values for phytase. Total P, soluble P, and inorganic soluble P in the litter were reduced when phytase was added to the diets. These data indicate that ME and AA values for phytase can be used in diet formulations for broilers with no loss in growth or yield performance, but a decrease in the P content of the litter will be observed.

Improvement of phosphorus availability by microbial phytase in broilers and pigs

Techniques have been developed to produce microbial phytase for addition to diets for simple-stomached animals, with the aim to improve phosphorus availability from phytate-P in plant sources. The activity of the crude microbial phytase showed pH optima at pH 5.5 and 2.5. The enzyme was able to degrade phytate in vitro in soya-bean meal, maize and a liquid compound feed for pigs. When microbial phytase was added to low-P diets for broilers the availability of P increased to over 60% and the amount of P in the droppings decreased by 50%. The growth rate and feed conversion ratio on the low-P diets containing microbial phytase were comparable to or even better than those obtained on control diets. Addition of microbial phytase to diets for growing pigs increased the apparent absorbability of P by 24%. The amount of P in the faeces was 35% lower.