Escherichia Coli-derived Phytase Research Articles

Effect of an Escherichia coli-derived phytase and a carbohydrase-protease cocktail derived from Bacillus spp. on performance, digestibility, bone mineralization and gut morphology in broilers fed different nutrient density diets.

Enzyme combinations, particularly phytase (PHY) with various carbohydrases and proteases, are utilized in commercial broiler production to enhance nutrient and energy bioavailability. A feeding study was undertaken to determine whether the efficiency of an Escherichia coli-derived PHY and a feed enzyme complex (FEC) derived from Bacillus spp. containing carbohydrase and protease as main activities in broiler chickens is dependent on diet quality. A total of 900 male one-day-old broiler chickens (Ross 308) were assigned to a 2×3 factorial arrangement of the treatments with 2 different nutrient density diets, standard nutrient diet (SN diet) and a low-nutrient diet (LN diet; -100kcal/kg for AMEn and -5% for crude protein [CP] and limiting amino acids), and 3 enzyme treatments (control [no enzymes], PHY and PHY+FEC). Each treatment group was composed of 6 replicates of 25 birds each. The LN diet caused a decrease in performance index, tibia length and diameter, tibia calcium content and jejunal villus surface area (VSA). The interaction effects between diet and enzyme supplementation were observed (p<0.05) on overall average daily gain (ADG), performance index, tibia ash content and jejunal villus height (VH) and VSA, with the favourable benefits of PHY+FEC treatment being more pronounced in the LN diets. Regardless of dietary nutrient density, supplementation with PHY alone or combined with FEC enhanced (p<0.05) final body weight, overall ADG and jejunal villus height (VH)/crypt depth, with the highest values observed in the PHY+FEC group. The PHY+FEC treatment also improved (p<0.05) overall feed conversion ratio, apparent ileal digestibility of dry matter, organic matter, CP, and energy, and tibia phosphorus content compared to the control treatment. The results indicate that the simultaneous addition of PHY and FEC to the LN diets improved the growth rate, bone mineralization and gut morphology.

Determination and validation of available phosphorus equivalency of Escherichia coli-derived phytase in broiler diets

The objective of this experiment was to determine and validate the available phosphorus (AP) equivalency of Escherichia coli -derived phytase (ECP) in broiler diets. A total of 960 eight-d-old broiler chicks were subjected to 8 dietary treatments with 10 replicates. The positive control (PC) diet contained recommended amounts of calcium (Ca) and AP, whereas the negative control (NC) diet was formulated to contain 0.76% calcium and 0.10% AP. The remaining 6 diets included varying levels of AP from monosodium phosphate (MSP) or ECP. Nonlinear regression analysis indicated that AP equivalency values of 500 and 1,000 FTU/kg ECP were 0.986 and 1.589 g/kg, respectively. These values were validated in a subsequent growth trial. A total of 2,000 eight-d-old broiler chicks were randomly allotted to 1 of 5 dietary treatments with 8 replicates. Five treatments included negative control diet 1 (NC1, highly deficient in AP and Ca), negative control diet 2 (NC2, deficient in AP and Ca), phytase diet 1 (P1, NC1 + 1,000 FTU/kg ECP), phytase diet 2 (P2, NC2 + 500 FTU/kg ECP), and positive control diet (PC, recommended concentrations of AP and Ca). Results indicated that birds fed diets supplemented with 500 or 1,000 FTU/kg ECP had similar growth performance and tibia characteristics compared with those fed PC diets. In conclusion, AP equivalency values of 0.986 and 1.589 g/kg AP determined for 500 and 1,000 FTU/kg ECP, respectively, can be applicable in commercial broiler diets.

Efficacy and phosphorus equivalency values of two bacterial phytases (Escherichia coli and Citrobacter braakii) allow the partial reduction of dicalcium phosphate added to the diets of broiler chickens from 1 to 21 days of age

The objective of this study was to determine the efficacy and the phosphorus equivalency of two bacterial phytases (Citrobacter braakii-derived phytase or genetically-modified Escherichia coli phytase) in the diets of broiler chickens from 1 to 21days of age. A total of 2100 male broiler chickens were randomly distributed in 10 treatments with 10 replicates of 21 chicks each. A basal diet was formulated containing 1.8g per kg of non-phytate phosphorus and 9g per kg of total calcium (T1). For treatments 2–4, dicalcium phosphate was added to give 0.9, 1.8, or 2.7g per kg of additional inorganic phosphorus. The treatments from 5 to 7 received 500, 1000, or 2000 phytase units of Citrobacter braakii (FYT) per kg while the treatments from 8 to 10 received 250, 500, or 1000 phytase units of Escherichia coli (FTU) per kg. Increasing levels of inorganic phosphorus from dicalcium phosphate at 0.9, 1.8, and 2.7g per kg improved (P<0.05) feed intake by 52, 71, and 80%; weight gain by 41, 75, and 32%; tibia ash weight by 64, 156, and 185%; and tibia phosphorus by 110, 323, and 378%, respectively. Increasing levels of Citrobacter braakii-derived phytase at 500, 1000, and 2000 FYT per kg contributed to a significant improvement (P<0.05) of 52, 55, and 65% for feed intake; 37, 56, and 65% for weight gain; 52, 87, and 133% for tibia ash weight; and 96, 173, and 273% for tibia phosphorus, respectively. Increasing levels of Escherichia coli-derived phytase at 250 to 500, and 1000 FTU per kg increased (P<0.05) feed intake by 50, 61, and 70%; weight gain by 49, 60, and 76%; tibia ash weight by 80, 103, and 164%; and tibia phosphorus by 128, 198, and 330%. Linear regression equations (P<0.05) were used to estimate phosphorus equivalency values of the two phytases. The Citrobacter braakii- and Escherichia coli-derived phytases can be used in the diets of broiler chickens from 1 to 21days of age to partially reduce the addition of dicalcium phosphate as a phosphorus source. The supplementation of 500, 1000, and 2000 phytase units of Citrobacter braakii per kg were determined to be equivalent to the average addition of 0.625, 1.091, and 2.024g of inorganic phosphorus from dicalcium phosphate per kg in broiler diets, respectively. The supplementation of 250, 500, and 1000 phytase units of Escherichia coli per kg were determined to be equivalent to the average addition of 0.763, 1.307, and 2.395g of inorganic phosphorus from dicalcium phosphate per kg in broiler diets, respectively.

Histomorphology and small intestinal sodium-dependent glucose transporter 1 gene expression in piglets fed phytic acid and phytase-supplemented diets1

An experiment was conducted to determine the effect of dietary phytic acid (PA) and phytase supplementation on small intestinal histomorphology and Na-dependent glucose transporter 1 (SGLT1) gene expression in piglets. Twenty-four piglets with an average initial BW of 7.60 ± 0.73 kg were randomly assigned to 3 experimental diets, to give 8 piglets per diet. The diets were a casein-cornstarch-based diet that was supplemented with 0 or 2% PA, or 2% PA (as Na phytate) plus an Escherichia coli-derived phytase at 500 phytase units/kg. The basal diet was formulated to meet the 1998 NRC energy, digestible AA, mineral, and vitamin requirements for piglets. After 10 d of feeding, the piglets were killed to determine small intestinal histomorphology and small intestinal SGLT1 gene expression. Phytic acid supplementation did not affect (P > 0.1) villus height (VH) and the VH-to-crypt depth (CD) ratio, but did decrease (P < 0.05) CD in the jejunum. Phytase supplementation did not affect (P > 0.1) VH, CD, and the VH-to-CD ratio. Phytic acid supplementation reduced SGLT1 gene expression in the duodenum, jejunum, and ileum by 1.1-, 5.4-, and 2.4-fold, respectively. Phytase supplementation increased SGLT1 gene expression in the jejunum by 2.6-fold, but reduced SGLT1 gene expression in the duodenum and ileum by 2.0- and 4.0-fold, respectively. In conclusion, PA reduced CD in the jejunum and SGLT1 gene expression in the duodenum, jejunum, and ileum, whereas phytase supplementation increased the expression of SGLT1 in the jejunum. The reduced SGLT1 gene expression by PA implies that PA reduces nutrient utilization in pigs partly through reduced expression of SGLT1, which is involved in glucose and Na absorption. The increased expression of SGLT1 in the jejunum by phytase supplementation implies that phytase alleviated the negative effects of PA partly through increased expression of SGLT1.

Phytase supplementation improved growth performance and bone characteristics in broilers fed varying levels of dietary calcium

An experiment was conducted to investigate the effect of dietary Ca level on the efficacy of phytase. A total of 288 male Ross × Ross 708 broilers with initial and final BW of 37 and 705 g, respectively, were used in brooder batteries from 0 to 21 d posthatch. Each treatment had 8 replications with 6 broilers/replicate pen. All diets were corn-soybean meal based and formulated to contain 1.26% total Lys. The treatments were positive control with 0.45% nonphytate P and 1% Ca and a negative control with 0.20% nonphytate P with 0.67, 1.00, or 1.33% Ca fed with or without 500 phytase units of Optiphos (Escherichia coli-derived phytase; JBS United Inc., Sheridan, IN). Increasing Ca from 0.67 to 1.33% linearly decreased (P ≤ 0.003) ADG, ADFI, bone breaking strength, bone weight, tibia ash weight, and percentage tibia ash; however, quadratic effects were found for ADFI, G:F, percentage tibia ash, and mortality (P ≤ 0.09). Phytase supplementation increased (P < 0.001) ADG, ADFI, bone breaking strength, bone weight, ash weight, and percentage tibia ash and decreased (P = 0.054) mortality. The increase in ADG, ADFI, bone weight, ash weight, and percentage tibia ash (P ≤ 0.026) and decrease in mortality (phytase × Ca linear; P = 0.058) from phytase supplementation was greater in broilers fed the higher levels of Ca. Calcium utilization was linearly decreased (P < 0.002) with increasing Ca. Phosphorus digestibility and utilization were increased with increasing levels of Ca (P ≤ 0.002); however, P utilization decreased at 1% Ca and increased at 1.33% (quadratic; P < 0.070). Phytase supplementation increased Ca utilization (P < 0.024), P digestibility (P < 0.001), and P utilization (P < 0.029). However, the increase in P digestibility (phytase × Ca; P < 0.021) was greater at the lower levels of Ca whereas P utilization (phytase × Ca; P < 0.001) was greater at 1.33% Ca with phytase supplementation. The results of this research indicate that dietary Ca level, within the ranges used in this experiment, does not negatively affect the efficacy of phytase.

Corn Expressing an Escherichia Coli-Derived Phytase Gene: Comparative Evaluation Study in Broiler Chicks

The efficacy of corn expressing an Escherichia coli- derived gene (corn-based phytase; CBP) and an E. coli-derived microbial phytase (expressed in Pichia pastoris) sprayed onto a wheat carrier (Quantum) was comparatively evaluated in two 14-d broiler chicken studies. In experiment 1, a total of 288 seven-day-old male broiler chicks were grouped by weight into 8 blocks of 6 cages, with 6 birds per cage, and used to measure growth performance, bone mineralization, and nutrient utilization. In experiment 2, a total of 192 seven-day-old male broiler chicks were used, with 4 birds per cage. Six dietary treatment groups were randomly allotted to the cages within each of 8 blocks. The corn-soybean meal-based diets used in each study consisted of a positive control adequate in P and Ca; a negative control (NC) low in P and Ca (no added inorganic P); the NC supplemented with 3,630, 36,300, or 363,000 phytase units (FTU) of CBP/kg; and the NC + 3,630 FTU of Quantum/kg. Growth performance and bone mineralization criteria were reevaluated in the second broiler study. Data from the 2 experiments were combined because there was no diet × experiment interaction and analyzed as a randomized complete block design. Weight gain decreased (P < 0.05) with a reduction in dietary P and Ca in the NC diet. Weight gain, feed efficiency, and percentage of tibia ash of birds fed 3,630 FTU/kg of either CBP or Quantum phytase were not different. There was a quadratic response (P < 0.01) to CBP supplementation of the NC diets in weight gain of the broiler chicks. Feed intake increased quadratically (P < 0.01) with CBP supplementation of the NC diets, but CBP supplementation of the NC diets did not affect feed efficiency. Tibia ash of birds fed the positive control diet was greater (P < 0.01) than that of birds fed the NC diet. There was a quadratic response (P < 0.01) to CBP supplementation of the NC diets in tibia ash of the broiler chicks. Birds fed supplemental phytase had greater (P < 0.01) ileal and total tract P and Ca digestibility than birds fed the NC diet. Data from the study suggest that E. coli phytase expressed in corn is efficacious in P-deficient broiler chick diets for the improvement of growth performance and indices of P utilization, which would minimize the need for supplemental P in broiler diets.

Effects of Phytate and Phytase on the Performance and Immune Function of Broilers Fed Nutritionally Marginal Diets

The effects of phytate and phytase on broiler performance and cellular and humoral immunity was assessed by using 504 Cobb 500 female broilers fed nutritionally marginal diets. At 1 d of age, the chicks were randomly allocated to 6 treatments in a 2 × 3 factorial arrangement including 2 levels of phytate P (0.22 or 0.44%) and 3 dose rates of an Escherichia coli-derived phytase [0, 500, or 1,000 phytase units (FTU)/kg of feed]. Both low- and high-phytate diets were corn and soy based with the same nutritional specifications (AME 2,900 kcal/kg, CP 21.00%, Ca 0.78%, and nonphytate P0.28%), differing only in the concentration of phytate P. The immune status of birds was measured at 14, 21, and 28 d of age. The results revealed that phytase improved feed intake, BW, and feed conversion ratio (P < 0.05), whereas high dietary phytate depressed bird performance (P < 0.05). There was no interaction between phytate and phytase on bird performance. Feeding phytase increased the percentages of erythrocyte rosette-forming cells and erythrocyte-antibody complement cells by 3.03 and 1.83% at d 21, and by 2.76 and 2.20% at d 28, respectively (P < 0.05). The percentages of CD4+ CD8+ T lymphocyte subsets were also increased by phytase (P < 0.05), without affecting the ratio of CD4+ and CD8+. The levels of intestinal secretory IgA were improved with phytase at d 14, 21, and 28 (P < 0.05). Antibodies against Newcastle disease virus vaccine were enhanced at d 21 and 28 in the high-phytate diets with phytase addition (P < 0.05). Increasing the phytase dose to 1,000 FTU/kg did not improve immune function further than 500 FTU/kg. The results suggest that application of phytase in nutritionally marginal diets could enhance lymphocyte numbers and the seral and mucosal antibodies of 1- to 28-d-old broilers, suggesting that both phytate and phytase may have a role in gastrointestinal health and immune competence.

Effects of dietary phytase on performance and nutrient metabolism in chickens

1. A broiler growth study was conducted to compare the effect of different concentrations of an Escherichia coli-derived phytase on performance, apparent metabolisable energy (AME), nitrogen (N), amino acid and mineral metabolisability, sialic acid excretion and villus morphology when fed to broiler chickens. 2. Female Ross 308 broilers (480) were reared in floor pens from 0 to 28 d of age. All birds were fed on nutritionally complete starter (0 to 21 d of age) and grower diets (21 to 28 d of age) with the exception that they were low in P (28 and 23 g/kg available P, respectively). These maize–soy diets were supplemented with 0, 250, 500 or 2500 phytase units (FTU)/kg feed. 3. Between 21 and 28 d of age, two birds from each floor pen were selected, and each pair placed in one of 32 metabolism cages (two birds per cage). Feed intake was recorded and excreta collected for the last 2 d of the feeding period, and AME, N, amino acid and mineral metabolisability coefficients and endogenous losses were determined following a total collection procedure. 4. Feed intake and weight gain increased in a linear manner in response to phytase dose, with an average increase of approximately 11·7 and 13·5%, respectively, compared with chickens fed on the low-P diet. Birds given diets with 2500 FTU weighed 6·6% more and had a 2·4% higher feed conversion efficiency (FCE) than those fed on diets containing 500 FTU. 5. Enzyme supplementation increased the intake of AME and metabolisable N by 10·3 and 3·9%, respectively, principally through increases in feed intake. Birds given enzyme-supplemented diets also improved their intake of metabolisable amino acids and P by approximately 14 and 12·4%, respectively, compared with birds fed on the control diet. Enzyme supplementation did not affect ileal villus morphometry of the birds. †Dr O. Oduguwa is visiting scientist from University of Agriculture, PMB 2240, Abeokuta, Nigeria.

Corn expressing an Escherichia coli-derived phytase gene: A proof-of-concept nutritional study in pigs1

Two experiments were conducted to investigate the concept that the addition of corn expressing an Escherichia coli-derived gene (corn-based phytase; CBP) to a P-deficient diet would improve growth performance and P utilization in pigs. An E. coli-derived microbial phytase (expressed in Pichia pastoris) sprayed onto a wheat carrier (Quantum) was included for comparison. In Exp. 1, forty-eight 10-kg pigs were blocked by BW into 6 blocks and allotted to 8 dietary treatments such that the BW among dietary treatments was similar and given free access to feed for 28 d. The dietary treatments were a negative control (NC) with no inorganic P supplementation; NC + 2, 4, or 6 g of monosodium phosphate/kg; NC + 16,500, 33,000, or 49,500 phytase units (FTU) of CBP/kg; and NC + 16,500 FTU of Quantum/kg. In Exp. 2, twenty-four 13-kg barrows were assigned to the NC, NC + 16,500 or 33,000 FTU of CBP/kg, or NC + 16,500 FTU of Quantum/kg, in a nutrient- and energy-balance study consisting of 5 d of adjustment and 5-d collection periods. The total collection method was used to determine nutrient and energy balance. Addition of CBP to the low-P NC diet linearly increased (P < 0.01) ADG, G:F, and plasma P concentration of pigs during the 28-d study. There was no difference in ADG, G:F, or plasma P concentration between pigs fed the CBP or Quantum phytase at 16,500 FTU/kg. Weight gain, G:F, and plasma P concentration of pigs increased (P < 0.01) with monosodium phosphate supplementation, confirming P deficiency of the NC diet. Linear improvements (P < 0.05) in DM digestibility and energy retention were observed with CBP supplementation of the NC diet. Although there were linear (P < 0.01) and quadratic (P < 0.05) increases in N digestibility, N retention was unaffected by CBP supplementation of the NC diet in growing pigs. Phosphorus and Ca digestibilities and retentions improved linearly and quadratically (P < 0.01) with the addition of CBP to the NC diet. There was no difference in digestive utilization of P or Ca between pigs fed CBP and Quantum phytase at 16,500 FTU/kg. The data showed that the addition of a corn expressing an E. coli-derived gene to a P-deficient diet improved growth performance and indices of P utilization in pigs, and corn expressing phytase was as efficacious as Quantum phytase when supplemented in P-deficient diets for weanling pigs.

Efficacy and equivalency of an Escherichia coli-derived phytase for replacing inorganic phosphorus in the diets of broiler chickens and young pigs1

Two studies were conducted to determine the efficacy of an Escherichia coli-derived phytase (ECP) and its equivalency relative to inorganic phosphorus (iP) from monosodium phosphate (MSP). In Exp. 1, one thousand two hundred 1-d-old male broilers were used in a 42-d trial to assess the effect of ECP and iP supplementation on growth performance and nutrient digestibility. Dietary treatments were based on corn-soybean meal basal diets (BD) containing 239 and 221 g of CP, 8.2 and 6.6 g of Ca, and 2.4 and 1.5 g of nonphytate P (nPP) per kg for the starter and grower phases, respectively. Treatments consisted of the BD; the BD + 0.6, 1.2, or 1.8 g of iP from MSP per kg; and the BD + 250, 500, 750, or 1,000 phytase units (FTU) of ECP per kg. Increasing levels of MSP improved gain, gain:feed, and tibia ash (linear, P < 0.01). Increasing levels of ECP improved gain, gain:feed, tibia ash (linear, P < 0.01), apparent ileal digestibility of P, N, Arg, His, Phe, and Trp at d 21 (linear, P < 0.05), and apparent retention of P at d 21 (linear, P < 0.05). Increasing levels of ECP decreased apparent retention of energy (linear, P < 0.01). Five hundred FTU of ECP per kg was determined to be equivalent to the addition of 0.72, 0.78, and 1.19 g of iP from MSP per kg in broiler diets based on gain, feed intake, and bone ash, respectively. In Exp. 2, forty-eight 10-kg pigs were used in a 28-d trial to assess the effect of ECP and iP supplementation on growth performance and nutrient digestibility. Dietary treatments consisted of a positive control containing 6.1 and 3.5 g of Ca and nPP, respectively, per kg; a negative control (NC) containing 4.8 and 1.7 g of Ca and nPP, respectively, per kg; the NC diet plus 0.4, 0.8, or 1.2 g of iP from MSP per kg; and the NC diet plus 500, 750, or 1,000 FTU of ECP per kg. Daily gain improved (linear, P < 0.05) with ECP addition, as did apparent digestibility of Ca and P (linear, P < 0.01). Five hundred FTU of ECP per kg was determined to be equivalent to the addition of 0.49 and 1.00 g of iP from MSP per kg in starter pigs diets, based on ADG and bone ash, respectively.

Influence of an Escherichia coli-Derived Phytase on Nutrient Utilization in Broiler Starters Fed Diets Containing Varying Concentrations of Phytic Acid

The influence of an Escherichia coli-derived phytase, on nutrient utilization was investigated in broilers fed starter diets containing different concentrations of phytate. The study was conducted as a 3 × 4 factorial arrangement of treatments with 3 concentrations of phytic acid (10.4, 11.8, and 13.6 g/kg; equivalent to 2.8, 3.3, and 3.8 g of phytate P/kg) and phytase (0, 500, 750, and 1,000 FTU/kg). One unit of phytase (FTU) is defined as the quantity of enzyme that releases 1 μmol of inorganic phosphorus/min from 0.00015 mol/L of sodium phytate at pH 5.5 at 37°C. The dietary phytic acid concentrations were manipulated by the inclusion of rice bran. Increasing dietary concentrations of phytic acid resulted in reductions (P < 0.01) in AME. Phytase additions tended to increase AME (P = 0.07), regardless of dietary phytate concentrations. Apparent ileal digestibility coefficients of protein and most amino acids were influenced by phytate (P < 0.05 to 0.001) and phytase (P < 0.001). Phytase improved ileal protein and amino acid digestibility at all phytate concentrations, but the trend in responses to increasing phytase additions was different at different phytate concentrations as shown by significant phytate × phytase interactions (P < 0.01 to 0.001). At the lowest phytate concentration, the ileal digestibility coefficients increased with increasing phytase supplementation. At the medium and high phytate concentrations, the greatest responses were observed at 500 FTU/kg of phytase, with little improvement attributable to further additions. Ileal digestibility of P was lowered (P < 0.01) by increasing phytate concentrations and increased (P < 0.001) with increasing additions of phytase. A significant phytate × phytase interaction (P < 0.05) was also observed, where the improvements in P absorption with added phytase were found to be greater at high phytate concentrations. These data demonstrate the anti-nutritive effects of phytic acid and the potential of microbial phytase to improve energy utilization and the availability of P and amino acids in broilers fed starter diets.

Phytase activity along the digestive tract of the broiler chick: A comparative study of an Escherichia coli-derived and Peniophora lycii phytase

Residual activity of an Escherichia coli-derived phytase and a commercially available Peniophora lycii phytase along the digestive tract of broiler chicks was compared in order to evaluate their relative resistance to hydrolysis in the digestive tract. Seventy-two 7-d-old male broiler chicks were grouped by weight into six blocks of three cages with four birds per cage. Three corn-soybean meal-based diets were randomly assigned to cages within each block. The three diets were a low P diet containing 3.9 g P kg-1 diet; and low P diet plus either E. coli-derived phytase or the P. lycii phytase at 1000 units kg-1 of feed. The chicks were fed experimental diets from 8 to 22 d of age. At the end of the study, chicks were killed and the contents of the crop, proventriculus and gizzard, jejunum and ileum were collected, freeze-dried, ground and analyzed for phytase activity. Escherichia coli-derived phytase had more residual activity at the proventriculus and gizzard, jejunum and ileum when compared with the P. lycii phytase (P &lt; 0.0001). The E. coli-derived phytase may be more resistant to hydrolysis in the digestive tract when compared with the P. lycii phytase. Key words: Broiler chick, Escherichia coli phytase, residual phytase activity

The efficacy of an Escherichia coli-derived phytase preparation.

Five experiments were conducted to evaluate the effect of an Escherichia coli-derived phytase on phytate-P use and growth performance by young pigs. The first experiment involved time course, pH dependence, and phytase activity studies to investigate the in vitro release of P from corn, soybean meal, and an inorganic P-unsupplemented corn-soybean meal negative control diet. In Exp. 2, which was designed to determine the efficacy of the E. coli-derived vs. fungal phytase-added diets at 0, 250, 500, 750, 1,000, or 1,250 FTU/kg (as-fed basis; one phytase unit or FTU is defined as the quantity of enzyme required to liberate 1 micromol of inorganic P/min, at pH 5.5, from an excess of 15 microM sodium phytate at 37 approximately C) and a positive control diet, eight individually penned 10-kg pigs per diet (12 diets, 96 pigs) were used in a 28-d growth study. The third experiment was a 10-d nutrient balance study involving six 13-kg pigs per diet (four diets, 24 pigs) in individual metabolism crates. In Exp. 4, eight pens (four pigs per pen) of 19-kg pigs per treatment were used in a 42-d growth performance study to examine the effect of adding the E. coli-derived phytase to corn-soybean diets at 0, 500, or 1,000 FTU/kg (as-fed basis) and a positive control (four diets, 128 pigs). In Exp. 5, six 19-kg pigs per treatment were used in a 10-d nutrient balance study to investigate the effects of the E. coli-derived phytase added to diets at 0, 250, 500, 750, or 1,000 FTU/kg (as-fed basis) and a positive control diet (six diets, 36 pigs). The in vitro study showed that the E. coli-derived phytase has an optimal activity and pH range of 2 to 4.5. Inorganic phosphate release was greatest for soybean meal, least for corn, and intermediate for the negative control diet. Dietary supplementation with graded amounts of E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain, feed efficiency, and plasma Ca and P concentrations in 10-kg pigs in Exp. 2. Phytase also increased P digestibility and retention in the 13-kg pigs in Exp. 3. In Exp. 4, dietary supplementation with E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain and feed efficiency of 19-kg pigs. Supplementation of the diets of 19-kg pigs with the E. coli-derived phytase also improved Ca and P digestibility and retention in Exp. 5. In the current study, the new E. coli-derived phytase was efficacious in hydrolyzing phytate-P, both in vitro and in vivo, in young pigs.