Phytase Inclusion Research Articles

Impacts of age and calcium on Phytase efficacy in broiler chickens

A total of 648 straight-run hatchling Heritage 56M × fast feathering Cobb 500F broiler birds were used to determine the effects of Ca concentration and age on phytase efficacy. Corn and SBM based diets with 0.19% non-phytate P were prepared with three Ca (6.5, 8.0 and 9.5 g/kg) concentrations. A 6-phytase55Danisco Animal Nutrition, DuPont Industrial Biosciences, Marlborough, UK was added on-top at 0, 500 or 1000 FTU/kg at each Ca concentration, resulting in a total of 9 treatments. Broiler birds were fed the diets for 2 d either from 7 to 9 (6 birds/replicate) or 19 to 21 (3 birds/replicate) d of age, and ileal content was collected from every bird at the end of each feeding period to determine apparent ileal digestibility coefficient (AID). Age effect was determined by comparing responses between birds fed from 7 to 9 and 19 to 21 d of age. There was no interaction between Ca and phytase on AID P regardless of age. Increasing Ca from 6.5 to 9.5 g/kg resulted in 12 (0.58 vs. 0.51) and 11% (0.64 vs. 0.57) reduction in AID P, in 9-d-old and 21-d-old birds, respectively (P < .05). Compared to birds fed diets without phytase, AID P was 100 and 155% greater in 9 d old birds fed 500 and 1000 FTU phytase/kg diets, respectively (P < .05). Similar but lesser improvement in AID P was also seen in 21 d old birds, with 63 and 76% improvement as a result of 500 and 1000 FTU/kg phytase inclusion, respectively (P < .05). Despite similar pattern in response to Ca and phytase, the degree of dietary impact and efficacy of phytase was affected by age of birds. In the absence of phytase, detrimental effect of Ca was more apparent in 9 d old than 21 d old bird, where greater difference in AID P was seen when Ca increased from 6.5 to 9.5 g/kg. With phytase inclusion, differences in AID P between 9 and 21 d old birds were reduced, which was more apparent with higher phytase and Ca inclusion. Net improvement of digestible P for 500 and 1000 FTU phytase/kg was 1.55 and 2.42, 1.45 and 1.72 g/kg, respectively for 9 and 21 d old birds. It is clearly shown that, even though birds at different ages responded to Ca and phytase similarly, the detrimental impact of Ca and benefit of phytase inclusion was greater in younger than older birds.

Subsequent somatic axis and bone tissue metabolism responses to a low-zinc diet with or without phytase inclusion in broiler chickens.

Zinc is required for normal bone development and cartilage formation. The purpose of this study was to assess the effect of with adding organic Zn (alone or phytase inclusion) at the reduced dose to growing male Ross 308 chickens on somatic axis and bone tissue metabolism. 200 one-day old broilers were divided into the negative control group fed diet without Zn or phytase inclusion, positive control group receiving Zn in the 100% of daily recommended dose from ZnO, and two experimental groups fed diet introduced Zn in 25% of daily recommendation as a glycine chelate (Zn-Gly) with or without phytase inclusion (500 FTU·kg-1). Supplemental organic Zn increased bone Zn and Mg content, serum IGF-1, growth hormone and leptin concentration. Additional phytase inclusion increased body weight gain, blood plasma Ca, Fe, Zn and osteocalcin concentration and tibia ash percentage when compared to the Zn-deprived control. Bone geometry, yield and ultimate strengths were enhanced in both organic Zn supplemented groups, and the overall mechanical strength parameters of bone were better in these groups than in the positive control group supplemented with standard dose of inorganic Zn. Also marked improvements in the thickness of articular and the growth plate cartilages as well as real bone volume and thickness of metaphyseal trabeculae were achieved in all broilers fed Zn-supplemented diet irrespective of phytase inclusion, however, the highest cancellous bone mass and the best trabecular structure were noted after ZnO supplementation. In concludion, although dietary organic Zn given to growing broilers in 25% of daily recommended dose improved general bone properties and mechanical strength, the obtained results do not allow to unambiguously state that organic Zn supplementation at this level, even after phytase inclusion, is sufficient for proper bone development.

Effect of the Phytase Inclusion in Broiler Breeder Diets on Fecal and Egg Characteristics

Effect of the Phytase Inclusion in Broiler Breeder Diets on Fecal and Egg Characteristics

Impacts of dietary calcium, phytate, and phytase on inositol hexakisphosphate degradation and inositol phosphate release in different segments of digestive tract of broilers

A total of 720 straight-run Heritage 56 M × fast feathering Cobb 500F broiler chickens was fed from 11 to 13 d of age to determine the impacts of dietary calcium (Ca), phytate phosphorus (PP), and phytase concentrations on inositol phosphate (IP3–6) profile in different digestive tract (GI) segments. The experiment was a 2 × 2 × 3 randomized block design with 2 Ca (0.7 and 1.0%) and 2 PP (0.23 and 0.34%) concentrations and 3 doses of Buttiauxella sp. phytase (0, 500, and 1,000 FTU/kg). The experiment was replicated in time (block) with 3 replicates per treatment (Trt) of 10 birds per block. Concentrations of IP3–6 in the crop, proventriculus (Prov) plus (+) gizzard (Giz), and distal ileum, as well as the ileal IP6 and P disappearance were determined at 13 d of age. The detrimental impact of Ca on IP6 and P disappearance was observed only in the ileum, where 11% reduction in both IP6 and P disappearance was seen when Ca increased from 0.7 to 1.0% (P < 0.05). Higher IP5 and IP6 concentrations were seen in both the crop and Prov+Giz at 0.34% PP as compared to birds fed to 0.23% PP diets, regardless of Ca or phytase (P < 0.05), whereas IP3 and IP4 concentrations were not affected by PP (P > 0.05). Inclusion of phytase, at both 500 and 1,000 FTU/kg, resulted in lower IP6 and the accumulation of lower IP ester (IP3–5) concentrations in all GI segments (P < 0.05). Improved IP6 and P disappearance was seen as a result of phytase inclusion, despite the degree of improvement affected by PP (P < 0.05). On average, 5.5 and 6.7 times improvement in IP6 was observed with 500 and 1,000 FTU phytase/kg inclusion, respectively, resulting in 41 and 64% greater P digestibility, respectively. In conclusion, phytase can effectively degrade IP6 to lower esters and increase P utilization. However, the efficacy of phytase can be affected by diet Ca and PP concentrations.

Effects of phytase inclusions in diets containing ground wheat or 12.5% whole wheat (pre- and post-pellet) and phytase and protease additions, individually and in combination, to diets containing 12.5% pre-pellet whole wheat on the performance of broiler chickens

Each of eight dietary treatments was offered to seven replicates (six birds per cage) of male Ross 308 chicks from 7 to 28days post-hatch. The diets contained 741g/kg wheat incorporated as ground (3.2mm hammer-mill screen) wheat or 125g/kg whole wheat included in diets, either pre- or post-pelleting. In Experiment 1 of the study, ground grain, pre-pellet and post-pellet whole grain diets were offered with and without phytase as a 3×2 factorial array of treatments. The effects of dietary treatments on gizzard and pancreas weights, bone mineralisation, excreta dry matter, growth performance, nutrient utilisation, digestibility coefficients and disappearance rates of starch and protein (N) in four small intestinal segments were determined. Post-pellet whole grain addition significantly increased gizzard weight by 12.5% (18.17 versus 16.15g/kg; P<0.001). Pre- and post-pellet whole grain additions improved FCR (P<0.10) by 1.40% and 2.28%, respectively. Exogenous phytase significantly enhanced weight gain by 4.76% (1519 versus 1450g/bird; P<0.001) and FCR by 1.99% (1.332 versus 1.359; P<0.03) irrespective of the context. Significant interactions between grain and phytase treatments were observed for energy utilisation parameters. However, pre- and post-pellet whole grain additions to non-supplemented diets significantly improved AMEn by 0.31MJ (11.89 versus 11.58MJ/kg; P<0.04) and 0.48MJ (12.06 versus 11.58MJ/kg; P<0.001), respectively. Post-pellet whole grain addition to non-supplemented diets significantly improved AME (13.49 versus 12.99MJ/kg; P<0.001) and ME:GE ratios (0.79 versus 0.77; P<0.003). Phytase addition significantly improved AME in ground grain and pre-pellet whole grain diets by 0.43MJ and 0.30MJ, respectively. Phytase addition improved AMEn by 0.49MJ in ground grain diets but this was not significant and otherwise did not influence AMEn. In Experiment 2, phytase and protease, individually and in combination, were included in diets containing 12.5% pre-pellet whole wheat as a 2×2 factorial treatment array. There was a significant interaction (P<0.015) for weight gain following phytase and protease additions to pre-pellet whole grain diets where phytase significantly increased weight gain by 6.91% (1548 versus 1448g/bird). Protease supplementation alone numerically increased weight gain, but in combination with phytase, numerically decreased weight gain. Phytase improved FCR by 2.15% (1.319 versus 1.348; P<0.01) and protease improved FCR by 1.41% (1.324 versus 1.343; P<0.05), but in combination, both feed enzymes improved FCR by 3.52% (1.317 versus 1.365; P<0.005) relative to the negative control. It is noteworthy that in the first experiment, whole wheat inclusions did not significantly influence starch digestibility but phytase inclusions increased distal ileal starch digestibility by 5.10% (0.948 versus 0.902; P<0.05) in pre-pellet and by 3.85% (0.943 versus 0.908; P<0.05) in post-pellet whole grain treatments.

Effects of graded levels of an Escherichia coli phytase on growth performance, apparent total tract digestibility of phosphorus, and on bone parameters of weanling pigs fed phosphorus-deficient corn-soybean meal based diets

An experiment was conducted to evaluate the efficiency of a novel Escherichia (E.) coli phytase on improving growth performance, calcium (Ca) and phosphorus (P) digestibility, and bone ash concentration of weanling pigs fed P-deficient corn-soybean meal based diets. Sixty weanling pigs with an initial body weight of 11.2±1.2kg were randomly allotted to 1 of 6 dietary treatments with 10 replicate pigs per treatment. The dietary treatments were: 1) positive control (PC), 2) negative control (NC), 3) NC+250 phytase units (FTU)/kg diet, 4) NC+500 FTU/kg diet, 5) NC+1000 FTU/kg diet, and 6) NC+2500 FTU/kg diet. Pigs were fed phase I diets during the initial 6days and phase II diets from day 7–27. At the end of the experiment, all pigs were euthanized to collect the 3rd and 4th metacarpals from each front foot. Results indicated that in both phase I and II, pigs fed the NC diet had reduced (P<0.05) apparent total tract digestibility (ATTD) of P compared with pigs fed the PC diet. However, inclusion of graded levels of E. coli phytase to the NC diet increased (linear and quadratic, P<0.01) the ATTD of P. No differences were observed in the ATTD of Ca or the ATTD of dry matter as E. coli phytase inclusion increased in the diets. Pigs fed the PC diet had greater (P<0.05) fat-free dried bone weight (g), bone ash weight (g), bone ash concentration (g/kg), bone Ca (g), and bone P (g and g/kg) and greater (P<0.05) average daily gain (ADG), average daily feed intake (ADFI), and gain: feed ratio (G:F) during phase II and during the overall experimental period than pigs fed the NC diet. Graded levels of E. coli phytase linearly and quadratically increased (P<0.05) fat-free dried bone weight (g), bone ash weight (g), bone ash (g/kg), bone Ca (g), and bone P (g). Inclusion of E. coli phytase also increased (linear, P<0.05) final body weight, ADG, ADFI and G:F during phase II and during the entire experimental period. No differences were observed between diets supplemented with 1000 or 2500 FTU/kg of E. coli phytase for fat-free dried bone (g), bone ash weight (g), bone ash (g/kg), bone Ca (g and g/kg), bone P (g) or final BW, ADG, ADFI, or G:F during phase II or during the overall experimental period. In conclusion, adding up to 1000 FTU/kg of the novel E. coli phytase to P-deficient diets increased growth performance and P utilization in weanling pigs.

Available phosphorus reduction in weaned piglets’ diets containing phytase combined with butyric and benzoic acids

This study aimed to evaluate the reduction of available phosphorus (Pa) in the diet of weaned piglets using phytase combined with butyric and benzoic acids. A total of 120 piglets with initial weight of 6.7 ± 0.02 kg were used in a randomized block design with six treatments: control; reduction of 0.15% Pa (Pa red); Phytase + Pa red; Phytase + butyric acid + Pa red; Phytase + benzoic acid + Pa red; Phytase + butyric acid + benzoic acid + Pa red; five replicates, with four animals each. The experimental diets had no influence on the fecal scores, Escherichia coli count, or the pH of the digestive tract. An improved villus:crypt ratio was found when the combination of phytase with butyric and benzoic acids was used. The histomorphometry of the jejunum and of the ileum showed no differences with respect to villus height, crypt depth, and villus:crypt ratio. The bones of the piglets fed with a diet containing reduced levels of available phosphorus showed less resistance to fracture. The levels of calcium in the raw bones were lower in the piglets that received a diet containing phytase and butyric acid. Reduced phosphorus deposition was observed in the bones of animals that received the diet containing phytase, butyric acid, and benzoic acid. It is concluded that the inclusion of phytase and butyric and benzoic acids, and their combination, in the diet of weaned piglets does not affect the pH of the stomach, duodenum, jejunum, ileum, cecum, and colon, and does not change the frequency of diarrhea or the E. Coli count. The association of butyric and benzoic acids with phytase in the diet of piglets after weaning improves the villus:crypt ratio of the duodenum. The use of phytase (1000 UF/kg) allows the formulation of diets for weaned piglets with a 0.15% reduction in the level of available phosphorus without damaging the concentration of calcium and phosphorus in the bones and without altering bone resistance.

Phytase dose effects in practically formulated diets that vary in ingredient composition on feed manufacturing and broiler performance

Considering approaches to efficiently produce broiler chickens, an experiment was conducted to describe the manufacturing and feeding effects of a corn, soybean meal, and wheat based diet with varying levels of corn distillers dried grains with solubles (DDGS) and commercial phytase. Treatments were arranged in a 3 × 2 factorial randomized complete block design varying in phytase (zero, 1,000, and 6,000 FTU/kg) and DDGS inclusion (zero or 5%). Phytase inclusion decreased dietary non-phytate phosphorous (nPP) and total Calcium (Ca) in formulation by 0.12 and 0.1%, respectively. Diets were steam conditioned at 82°C for 10 s, extruded through a 4.7 × 38 mm pellet die, and fed as crumbles (starter and grower) or pellets (finisher). Ten replicate pens of straight-run Hubbard × Cobb 500 chicks consumed one of 6 dietary treatments for 38 days. Phytase improved feed conversion ratio (FCR) in the starter period (P = 0.05), but benefits were not apparent in the grower or finisher periods. Phytase and formulation main effects interacted to affect overall FCR (P = 0.05), demonstrating a 0.05 decrease in FCR when birds were fed a diet containing a super-dose of phytase and without DDGS relative to diets containing a super-dose of phytase and DDGS. The DDGS likely provided reduced nutrient availability relative to their nutrient values used for diet formulation or provided non-starch polysaccharides (NSP) at a level that decreased bird performance. Based on tibia ash measures, performance improvement associated with the super-dose of phytase was likely associated with reducing phytate phosphorus gastrointestinal irritation rather than meeting bird phosphorus requirement.

&lt;b&gt;Phytase in diets with crude protein levels for commercial layers

The aim of this study was to evaluate the action of the phytase enzyme in diets formulated with variations in the crude protein content on performance and egg quality of commercial layers. A total of 336 commercial layers were housed at eight birds per cage in a 3 × 2 factorial arrangement with seven replicates. Treatments consisted of four crude-protein levels (17, 15, and 13%) and two enzyme levels (0 and 500 FTU kg-1 diet), distributed in a completely randomized design. Feed intake, egg production, feed conversion per dozen eggs and per kilogram, egg weight and mass, specific gravity, eggshell thickness, and Haugh unit were measured over five 28-day periods. The performance of commercial layers fed the diet containing 13% crude protein worsened, irrespective of phytase addition. However, at 15% crude protein, phytase inclusion did not affect feed conversion or egg weight. Inclusion of phytase leads to equal egg-quality and performance results at the dietary crude protein levels of 17 and 15%. The crude protein content of 13%, with or without phytase, is not recommended for the diet of brown-egg layers.

Effects of exogenous phytase supplementation on phosphorus metabolism and digestibility of beef cattle.

Objectives were to determine interactions between phytase inclusion and dietary P concentration on P utilization by beef cattle fed a starch-based diet. Six ruminally-fistulated steers (BW = 750 ± 61 kg) were allotted to a 6 × 6 Latin square design with a 3 × 2 factorial arrangement of treatments. Factors included phytase inclusion, at 0, 500, or 2,000 phytase units (FTU)/kg of diet DM, and dietary P concentrations, at 0.10% and 0.30% of total diet DM. Feed ingredients, fecal samples, and orts were composited within period, lyophilized and ground. Samples were analyzed for NDF, ADF, CP, fat, ash, total P, and other minerals. Data were analyzed using the MIXED procedure of SAS with animal as the experimental unit. The CORR procedure was used to compare blood and urinary P concentrations. There were no treatment interactions (P ≥ 0.30) for any parameter measured. There were no main effects (P ≥ 0.45) of phytase inclusion on DMI, total fecal output, apparent DM digestibility, water intake, or urinary output. Steers fed 0.10% P had decreased (P < 0.01) DMI and total fecal output, but increased (P < 0.01) apparent DM digestibility compared with steers fed 0.30% P. Although N intake and retention were not affected by treatment, steers fed the 0.10% P diet tended (P = 0.10) to absorb more N compared with steers fed 0.30% P; and, steers fed the 0.10% P diets excreted more N in the urine (P = 0.02) and less N in the feces (P < 0.01) compared with steers fed the 0.30% P diets. Steers fed the 0.10% P diets also consumed 70.1% less (P < 0.01) total P each day, and excreted 51.9% less (P < 0.01) P in feces and 94.6% less P in the urine (P < 0.01) compared with steers fed 0.30% P. Excretion of water-soluble P in the feces was greater (P < 0.01) on a g/d basis for steers fed 0.30% P when compared with steers fed 0.10% P. However, the proportion of total fecal P excreted as water-soluble P increased (P < 0.05) by 23.0% in steers fed 0.10% P compared with steers fed 0.30% P, regardless of phytase inclusion level. There was no effect of dietary phytase concentration on blood or urinary (P ≥ 0.27) P concentrations. Blood P concentration was positively correlated (r = 0.60; P < 0.01) to urinary P concentration when steers were fed 0.10% P; however, when steers were fed 0.30% P, there was no correlation (r = 0.36; P = 0.16) between blood and urine P. Regardless of dietary P concentration, phytase supplementation did not increase calculated P absorption or retention.

The effect of poultry litter biochar on pellet quality, one to 21 d broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility

Feeding poultry litter biochar (PLB), a product resulting from litter gasification, could decrease diet cost, maintain broiler growth performance, and decrease land application of manure. Past research observed improved pellet quality and mineral availability with dietary inclusions of 6 to 7% PLB; however, broiler performance was decreased, likely due from toxic-heavy-metal content (e.g., 99 ppm arsenic) and increased digesta viscosity of the particular PLB. The objective of the current study was to assess lower dietary inclusions of PLB, with decreased toxic-heavy-metal content, on descriptive feed manufacture, broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility (AIAAD). Treatments were arranged as a Diet Formulation x Phytase Addition factorial in a randomized complete block design with 8 replications per treatment. Four dietary formulations were produced: positive control (PC) with 0.45% non phytate phosphorus (nPP), negative control with 0.23% nPP, and 2 or 4% PLB with 0.45% nPP. Phytase was either included at 9,500 ftu/kg or withheld. There were 8 treatments total. Contrasts comparing PC and 2 or 4% PLB also were conducted. Diets were pelleted and crumbled prior to feeding. Positive and negative control formulations and phytase addition affected bird performance as expected. Birds fed 2% PLB had increased FCR and birds fed 4% PLB had decreased LWG when compared to PC (P < 0.05). However, these performance deficiencies were corrected with phytase inclusion. Birds fed diets with PLB had similar tibia measures compared to the PC. No significant main effects, interactions, or contrast comparisons were observed for viscosity data. The incorporation of PLB into formulations without phytase increased diet AIAAD of some amino acids relative to the corresponding PC (P < 0.05). A lower toxic-heavy-metal PLB product (e.g., 22 ppm arsenic) provided available minerals and amino acids to diets, but performance similar to PC necessitated the addition of phytase.

Xylanase, protease and superdosing phytase interactions in broiler performance, carcass yield and digesta transit time.

The interaction of xylanase, protease and superdosing (1,500 FTU/kg) phytase in a 2 × 2 × 2 factorial arrangement was studied in broilers fed sorghum-based diets. A total of 2,800 one-day-old unsexed Ross 308 chicks were housed in 56 pens with 50 birds per pen, with or without inclusion of xylanase, protease and phytase, totaling 8 treatments and 7 replicates per treatment. Body weight (BW) and feed intake (FI) were measured at 21 and 42 days of age, and mortality corrected feed conversion ratio (FCR) was calculated for each period and cumulatively. Tibia ash and carcass yield were determined in 2 birds per replicate at 21 and 42 days of age, respectively. Digesta transit time was determined at 21, 28, 35 and 42 days of age using 5 birds per replicate. Results showed that superdosing phytase increased BW and FI at 42 days of age (P < 0.05) and xylanase improved FCR (P < 0.05). Xylanase and phytase also positively influenced carcass yield and breast weight, respectively. Overall, inclusion of superdosing phytase increased transit time when included in a diet containing xylanase, and no change with protease inclusion. In conclusion, the beneficial effects of xylanase, protease and superdosing phytase in broiler performance were not additive. This limitation is likely not related to the lack of efficacy of any one of the individual enzymes but to a limitation of the bird to respond additively to successive additions of enzymes.

Evaluation of increasing levels of a microbial phytase in phosphorus deficient broiler diets via live broiler performance, tibia bone ash, apparent metabolizable energy, and amino acid digestibility

The objective was to investigate increasing concentrations of an evolved microbial phytase on male broiler performance, tibia bone ash, AME, and amino acid digestibility when fed diets deficient in available phosphorus (aP). Experiment 1 evaluated the effects of phytase during a 21 d battery cage study and Experiment 2 was a 42 d grow-out. Experiment 1 included six treatments; negative control (NC) with an aP level of 0.23% (starter) and 0.19% (grower), two positive controls (PC) consisting of an additional 0.12% and 0.22% aP (PC 1 and PC 2), and the NC supplemented with three levels of phytase (250, 500, and 2,000 U/kg). The NC diet reduced (P < 0.05) FC, BW, and bone ash. Phytase increased (P < 0.05) BW with 2,000 U/kg phytase yielding similar results to the PC2, and improved FCR and increased bone ash was observed at all phytase levels. Amino acid digestibility coefficients were increased (P < 0.05) with phytase at 250 U/kg. Phytase at all rates increased (P < 0.05) AME to levels similar level as PC diets. Linear regression analysis indicated average P equivalency values for BW and bone ash of 0.137, 0.147, and 0.226 for phytase inclusion of 250, 500, and 2000 U/kg, respectively. Experiment 2 included a PC consisting of 0.45%, 0.41%, and 0.38% aP for the starter, grower, and finisher, respectively; NC with reduced aP of 0.17%; and phytase at 500 and 2,000 U/kg. Phytase increased BW (P < 0.05) compared to the NC as 2,000 U/kg phytase resulted in further BW increases compared to the PC (starter and grower). Phytase improved FCR to levels comparable to the PC, with supplementation at 2,000 U/kg resulting in improvements beyond the PC in the starter phase. Amino acid digestibility coefficients were increased with phytase at 2,000 U/kg to levels comparable to that of the PC. These data confirm that the inclusion of phytase improves broiler performance and bone mineralization in aP reduced diets and levels beyond the traditional 500 U/kg can result in further improvements.

Dose-dependent effects of a microbial phytase on phosphorus digestibility of common feedstuffs in pigs.

ObjectiveThe objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller’s dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat.MethodsTwo cohorts of 36 pigs each (initial body weight = 78.5±3.7 kg) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of TiO2 as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential p≤0.001) with the inclusion of phytase for all ingredients.ResultsBasal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients.ConclusionVariations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.

Effects of zinc oxide and microbial phytase on digestibility of calcium and phosphorus in maize-based diets fed to growing pigs.

An experiment was conducted to test the hypothesis that inclusion of Zn at a pharmacological level in diets fed to pigs affects apparent total tract digestibility (ATTD) of Ca and P and standardized total tract digestibility (STTD) of Ca. The second hypothesis was that inclusion of microbial phytase increases the ATTD of Ca and P and the STTD of Ca regardless of the concentration of Zn in the diet. Fifty-six growing barrows (15.4 ± 1.9 kg average BW) were allotted to a randomized complete block design with 7 dietary treatments and 8 pigs per treatment. A maize-based basal diet was formulated with either 0 or 2,400 mg/kg Zn from ZnO and 0, 1,000, or 3,000 units of phytase (FTU) per kilogram. A Ca-free diet was used to determine basal endogenous losses of Ca. Experimental diets were fed for 13 d, and feces were collected from the feed provided from d 6 to 11 using the marker-to-marker approach; urine was also collected from d 6 to 11. Retention of Ca, ATTD of Ca, and STTD of Ca increased ( < 0.01) as the concentration of phytase in the diet increased and were less ( < 0.01) if ZnO was used than if no ZnO was added to the diet. Retention of P and the ATTD of P increased ( < 0.0001) as the concentration of phytase increased in the diet, but the increase was greater if ZnO was not added than if ZnO was added to the diet (interaction, < 0.05). In conclusion, pharmacological levels of Zn reduced Ca and P digestibility and retention, but this effect was partly ameliorated by the inclusion of phytase in the diets. Inclusion of microbial phytase increased the ATTD and STTD of Ca in diets and also the ATTD of P.

Effect of a Buttiauxella phytase on production performance in growing/finishing pigs fed a European-type diet without inclusion of inorganic phosphorus

SummaryThe effect of a Buttiauxella phytase, in a dose range of 0-1000 FTU/kg in feed, on production performance in growing/finishing pigs fed European type wheat, corn, barley and SBM based diet was determined. Five dietary treatments were tested including a positive control (PC), a negative control (NC) without inorganic P and with reduced Ca (–0.12%) and metabolisable energy content (–0.14 MJ ME/kg) or NC supplemented with Buttiauxella phytase (Axtra® PHY, Danisco Animal Nutrition, DuPont Industrial Biosciences, Marlborough, UK) at 250, 500 or 1000 FTU/kg respectively. A total of 100 pigs (mean initial BW of 30 kg, Topig x Pi, 10 weeks of age) were used, with 20 replicates per treatment (50% gilts and 50% barrows). Pigs were individually housed in pens and randomly allocated on the basis of body weight (BW) and gender to the five treatments. Feed, in mash form, and water were offered ad libitum. Basal diets had an intrinsic phytase level of approximately 300 and 440 FTU/kg in NC grower and NC finisher diets respectively. Mean average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for the feeding phases of 30–85 kg (grower), 85–125 kg (finisher) on trial and for overall period. During the grower phase, increasing phytase dose resulted in a linear increase in ADG. Phytase inclusion at 250, 500 and 1000 FTU/kg improved ADG by 3.5, 7.2 and 8.1% respectively compared to NC and by 0.8, 4.5 and 5.3% respectively compared to those fed the PC. Performance in the finisher phase, overall period and slaughter parameters were not different between dietary treatments. The data showed that it was beneficial to increase phytase dose up to 1000 FTU/kg in grower pigs up to 85 kg BW. In the finisher phase, in pigs with BW above 85 kg, 500 FTU/kg was sufficient to replace inorganic P and maintain performance and carcass characteristics comparable to pigs fed the PC.

Phytase inclusions of 500 and 2000 FTU/kg in maize-based broiler diets impact on growth performance, nutrient utilisation, digestive dynamics of starch, protein (N), sodium and IP6 phytate degradation in the gizzard and four small intestinal segments

The objective was to investigate the effects of 500 and 2000FTU/kg phytase inclusions in maize–based diets with appropriately reduced nutrient specifications in comparison to a positive control diet. Diets were offered to Ross 308 broiler chickens from 7 to 28days post-hatch and growth performance, nutrient utilisation parameters, sodium, starch and protein (N) digestibility coefficients were obtained in four small intestinal segments and IP6 phytate degradation coefficients were determined in the gizzard and in four small intestinal segments. The transition from positive control to negative control diets compromised weight gains, FCR and toe ash by 10.3%, 6.57% and 11.5%, respectively. However, 2000FTU/kg phytase supplementation completely restored these parameters. At 500FTU/kg phytase significantly increased starch digestibility coefficients by 12.7% (0.879 versus 0.780) in the distal jejunum and by 4.41% (0.947 versus 0.907) in the proximal ileum and significantly increased starch disappearance rates in all four small intestinal segments. Significant increases in protein (N) digestibility and disappearance rates were limited to the proximal ileum where 500FTU/kg phytase increased protein (N) digestibility coefficients by 6.08% (0.785 versus 0.740). Phytase, at both inclusions, significantly increased the recovery of sodium in the three anterior small intestinal segments. Interestingly, sodium digestibility coefficients were correlated (P=0.051 − <0.001) with starch and protein (N) digestibility coefficients in all four small intestinal segments. The greatest IP6 degradation of 95.5% was observed in the gizzard from 2000FTU/kg phytase. However, surprisingly high gizzard IP6 degradation rates were observed in both non-phytase supplemented diets. In contrast, phytate degradation was far more pronounced in the negative control than the positive control diet in four small intestinal segments. This phytate degradation may be to the consequence of an up-regulation of endogenous mucosal phytase activity generated by the phosphorus deficient diet coupled with the lower calcium concentration facilitating mucosal phytase activity. Weight gain was correlated with phytate degradation in the gizzard (r=0.789; P<0.001) to a more significant extent than in the four small intestinal segments. Consideration is given to the possibility that phytase may be enhancing intestinal uptakes of glucose via Na+-dependent transport systems.

Endogenous losses and true digestibility of phosphorus in rice bran with or without phytase determined with piglets

ABSTRACT: The aim of this study was to determine endogenous losses and true total digestibility of phosphorus (P) in piglets fed with diets containing rice bran (RB), and supplemented or not with phytase. The experiment was divided into three periods of 12 days each, seven for adaptation and five for total feces collection, with an interval of three days between periods. Twelve barrows with average body weights of 13.40±1.00kg at 46 days of age were distributed among six treatments consisting of diets formulated with three levels of RB (5%, 10%, and 20%) with or without the addition of 750FTUkg-1 of phytase. The amount of total daily feed was divided into four daily meals and water was available ad libitum. The method of total feces collection was used with ferric oxide as the fecal marker. The total consumption of P of RB origin was 0.37, 0.85 and 1.73gd-1 for concentrations of 5%, 10% and 20% of RB, respectively. Both RB and phytase levels had an effect on the apparent digestibility of P in RB. Results of the regression analysis of ingested P originating from the RB and absorbed P indicated endogenous losses of 527mg of Pkg-1 of dry matter intake, independent of phytase. Additionally, the true digestibility of P in RB was 47%, and it was not influenced by the inclusion of phytase. We concluded that the addition of 750FTU of phytase does not affect endogenous losses or the true digestibility of P in RB.

Effects of production area and microbial phytase on the apparent and standardized total tract digestibility of phosphorus in soybean meal fed to growing pigs.

An experiment was conducted to determine if the area in which soybeans are grown influences the concentration of P, phytate, and macro- and microminerals in the soybean meal (SBM) produced from the beans and, therefore, also influences the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P in SBM. The second objective was to test the hypothesis that inclusion of microbial phytase will increase the ATTD and STTD of P in SBM regardless of where the beans were grown. Twenty sources of SBM were procured from crushing facilities located in different regions of the United States that were separated into 3 zones: 1) the northern growing area (Michigan, Minnesota, and South Dakota), 2) the eastern growing area (Georgia, Illinois, Indiana, and Ohio), and 3) the western growing area (Iowa, Missouri, and Nebraska). For each source of SBM, 2 diets based on cornstarch and SBM were formulated; one of these diets contained no microbial phytase and the other diet contained 500 units/kg of microbial phytase. Two hundred growing barrows (16.90 ± 1.79 kg initial BW) were individually placed in metabolism crates and allotted to a randomized complete block design with 40 diets and 5 replicate pigs per treatment. Feces were collected for 4 d after a 4-d adaptation period using the marker-to-marker procedure. Results indicated that there were no differences in concentration of Ca, P, phytate, and macro- and microminerals among SBM from the different zones. However, there was a tendency ( = 0.055) for an increase in concentration of nonphytate P in SBM from the western growing area (0.25%) compared with SBM from the northern growing area (0.23%) and the eastern growing area (0.23%). There were no differences in feed intake, absorbed P, ATTD of P, STTD of P, Ca intake, Ca output, or ATTD of Ca for pigs fed SBM from the 3 zones. However, there was a tendency (P = 0.066) for an increase in P intake and P output from pigs fed SBM from the western growing area compared with pigs fed SBM from the northern growing area. There was an increase ( < 0.05) in absorbed P, ATTD and STTD of P, and ATTD of Ca if microbial phytase was included in the diets, but the quantity of P and Ca that was excreted in the feces decreased ( < 0.001) if microbial phytase was used. Overall, no differences in ATTD and STTD of P exist among SBM produced in different areas of the United States, but microbial phytase will increase the digestibility of P in SBM.

The influence of meat-and-bone meal and exogenous phytase on growth performance, bone mineralisation and digestibility coefficients of protein (N), amino acids and starch in broiler chickens.

The objective of this study was to examine the influence of meat-and-bone meal (MBM) and phytase inclusion on growth performance, bone mineralisation and apparent digestibility coefficients of nutrients in broiler chickens offered wheat-based diets. The feeding study comprised 7 dietary treatments: positive control (PC, 9.0% Ca and 4.5% available phosphorous [AvP] in starter, 7.0% Ca and 3.5% AvP in finisher); negative control (NC, 7.2% Ca and 3.0% AvP in starter, 5.2% Ca and 2.0% AvP in finisher) diets incorporating a 3 × 2 factorial array of 3 MBM inclusions (0, 60, 120 g/kg) and 2 levels of phytase supplementation (0 and 1,000 FYT/kg). Each treatment was allocated to 6 replicated pens with 30 birds per pen in an environmentally-controlled deep litter facility. A total of 1,260 one-day-old male Ross 308 chicks were offered starter diets from 1 to 14 days post-hatch and finisher diets from 15 to 36 days post-hatch. There were significant (P < 0.05) interactions between MBM inclusions and phytase supplementation on weight gain and feed intake in starter diets. Phytase significantly increased weight gain in diets without MBM and did not influence weight gain in diets with 60 and 120 g/kg MBM. Collectively, increasing MBM inclusion significantly reduced weight gain in starter diets (P < 0.0001). There were dietary interactions (P < 0.01) on toe ash where phytase significantly improved toe ash in diet without MBM and did not influence toe ash in the other two groups of negative control diets. There were no dietary treatment interactions on apparent ileal digestibility coefficients of starch and protein except that diets without MBM had significantly (P < 0.01) lower ileal starch digestibility and diets with 120 g/kg MBM had significantly (P < 0.0001) lower ileal protein digestibility. No dietary influence on ileal fat digestibility was observed. There were dietary interactions on ileal digestibilities of isoleucine, valine and glycine. Phytase significantly increased glycine digestibility in diets with 60 and 120 g/kg MBM but not in diets without MBM. Including 120 g/kg MBM significantly (P < 0.01) depressed apparent digestibility coefficients of 13 ex 16 amino acids in the distal ileum. This study demonstrated the negative impacts of MBM on amino acid digestibility and growth performance. Also, responses to phytase were more pronounced in diets without MBM, which may have been due to their relatively lower available P and higher phytate concentrations in comparison to diets containing MBM.