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Cobb 400, male broilers (n = 4,752) were housed in 12 pens/diet and 33 birds/pen. There were 3 levels of phytate P (0.24, 0.345, or 0.45%) and 4 phytase doses (0, 500, 1,000 or 2,000 phytase units (FTU)/kg) to evaluate the influence of phytate and phytase dose on apparent ileal digestibility (AID) and digestible nutrient intake. Diets were formulated with reduced Ca (0.22%), available P (0.20%), energy (80 to 120 kcal/kg) and amino acids (1 to 5%). On day 21, digesta was collected from 8 birds/pen. Prediction equations determined the linear or non-linear influence of phytate P, log phytase dose, and the interaction. The AID of amino acids, Ca or P and digestible amino acid or Ca intake were influenced by linear or nonlinear phytate P × log phytase dose (P < 0.0001). Increasing the dietary phytate P from 0.24 to 0.345 or 0.45% was predicted to reduce the AID of amino acids in a non-linear manner by an average of 6 to 7 percentage points, respectively. This corresponded to a non-linear decrease in digestible amino acid intake of an average of 80 to 90 mg/D. The negative effect of increasing dietary phytate P from 0.24 to 0.45% on AID was greatest for cysteine (−14 percentage points), aspartic acid or glycine (−9 percentage points) and lowest for methionine, tryptophan, serine, or glutamic acid (−5 percentage points). The predicted digestible intake of lysine (−120 mg/D), aspartic acid (−180 mg/D), or glutamic acid (−290 mg/D) were reduced in birds fed diets containing 0.345% vs. 0.24% phytate P. Phytase supplementation was predicted to increase the AID of amino acids, Ca, or P in a non-linear-log or log-linear manner at all levels of phytate P, with the greatest response at higher doses of phytase in diets containing 0.345 or 0.45% phytate P. The effect of phytase on digestible nutrient intake was less clear. Prediction equations can be useful to determine the influence of phytase and phytate P on AID and digestible nutrient intake in broilers. [ABSTRACT FROM AUTHOR]

Cobb 400, male broilers (n = 4,752) were fed one of 12 diets, with 12 pens/diet and 33 birds/pen. Treatments consisted of 3 levels of phytate P (0.24, 0.345, or 0.45%) and 4 doses of phytase (0, 500, 1,000, or 2,000 phytase units (FTU)/kg). Diets were formulated with reduced Ca (0.22%), available P (0.20%), energy (80 to 120 kcal/kg), and amino acids (1 to 5%) when compared with breed requirements. Prediction equations suggested feeding dietary phytate P > 0.275, 0.295, or 0.319% reduced feed intake (FI) and body weight gain (BWG) and increased feed conversion ratio, respectively, from day 0 to 21. Supplementing phytase at 561, 1,285, or >2,000 FTU/kg resulted in the maximum FI, BWG, or feed efficiency, respectively. From day 0 to 42, maximum BWG or feed efficiency were achieved at phytate P concentrations <0.281 or 0.25%, respectively. Supplementing phytase at 449 or 2,000 FTU/kg maximized BWG or feed efficiency, respectively. Tibia ash weight, percent or Ca concentration were maximized at phytate P concentrations <0.24, 0.296, or 0.24%, respectively and phytase supplementation at 822 or >2,000 FTU/kg maximized tibia ash weight or percent respectively. In the absence of phytase, phytate (IP6) concentration in the gizzard was greatest in birds fed 0.45% phytate P and phytase supplementation between 1,132 to 1,285 FTU/kg resulted in the lowest IP6 concentration in the gizzard. There was no effect of dietary phytate P on the concentration of phytate esters (IP5 or IP4) in the gizzard, which were minimized at 1,208 FTU/kg of phytase. In the absence of phytase, the concentration of phytate ester (IP3) or inositol in the gizzard was greatest in birds fed 0.345% phytate P and phytase supplementation at ∼500 FTU/kg minimized IP3, whereas 2,000 FTU/kg maximized inositol, except in birds fed 0.45% phytate P, which was maximized at 202 FTU/kg of phytase. Prediction equations can be useful to determine the influence of phytase and phytate P on broiler performance, phytate degradation and bone ash. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate phytase, phytase + xylanase, or phytase + xylanase + protease in diets deficient in Ca, available phosphorus (avP), energy, and amino acids. Lohman Indian River, straight-run broilers (n = 2,304 and 4,752 in experiments 1 and 2, respectively) were fed one of eight diets: (1) nutrient adequate control (PC), (2) negative control (NC) 1 with reduced Ca and avP, (3) NC1 + 1,500 FTU/kg phytase, (4) NC2 with reduced Ca, avP and energy, (5) NC2 + 1,500 FTU/kg phytase + 16,000 BXU/kg xylanase, (6) NC3 with reduced Ca, avP, energy, and amino acids, (7) NC3 + 1,500 FTU/kg phytase + 16,000 BXU/kg xylanase, (8) NC3 + 1,500 FTU/kg phytase + 16,000 BXU/kg xylanase + 15,000 U/kg protease. Reducing Ca, avP, energy, and amino acids significantly reduced body weight gain (BWG) and feed efficiency in a sequential fashion, with birds fed NC3 having a significantly higher FCR compared with birds fed NC1 or the PC. In both experiments, supplementation with phytase, phytase + xylanase, or the combination of phytase + xylanase + protease significantly improved BWG and FCR comparable to the PC. However, there was no difference in BWG or FCR between birds fed phytase + xylanase or phytase + xylanase + protease. Results indicate that supplementation of phytase + xylanase restored the BWG and FCR of the birds fed reduced Ca, avP, energy, and amino acid diets, and supplementation of protease to diets containing phytase and xylanase needs further investigation. [ABSTRACT FROM AUTHOR]

Two experiments of the same design were conducted to determine the influence of phytase on performance and apparent ileal digestibility (AID) of amino acids in broilers fed graded concentrations of digestible sulfur amino acids (dgM+C). Cobb 400 male broilers were allocated to 1 of 10 diets consisting of 5 basal diets formulated at 75, 82, 89, 96, or 103% of the Cobb 400 dgM+C requirements for each feeding phase. Phytase was included in each basal diet at 0 or 2,000 FTU/kg. In experiment 1, 33 birds/pen from hatch to day 42 were fed a 2-phase feeding program with 10 replicate pens/diet. In experiment 2, there were 26 birds/pen from hatch to day 21 and 8 replicate pens/diet. Data were analyzed as a 5 × 2 factorial and means separated using orthogonal contrasts. In experiment 1, overall (hatch to day 42) feed intake (FI) decreased (linear, P < 0.05), body weight gain (BWG) increased (quadratic, P < 0.05), and feed conversion ratio (FCR) was improved (quadratic, P < 0.05) as dgM+C increased to ≥96% in the diet. Phytase increased (P < 0.05) BWG and improved (P < 0.05) FCR, regardless of the percent dgM+C in the diet. In experiment 2, overall (hatch to day 21) BWG increased (quadratic, P < 0.05), and FCR was improved (quadratic, P < 0.05) as dgM+C increased to ≥96% in the diet. Phytase increased FI (P < 0.05) and BWG (P < 0.05) and improved FCR (P < 0.05), regardless of the percent dgM+C in the diet. In the absence of phytase, the AID of all amino acids was greatest (quadratic, P < 0.05) in birds fed between 89 and 96% dgM+C. However, in the presence of phytase the AID of all amino acids was greatest (quadratic, P < 0.05) in birds fed 82% dgM+C and greater at all levels of dgM+C than birds fed diets without phytase (dgM+C × phytase, P < 0.05). In conclusion, phytase improved AID of all amino acids and improved growth performance regardless of the level of dgM+C in the diet. [ABSTRACT FROM AUTHOR]

Three experiments were conducted to evaluate eight neutral and six acid proteases on growth performance and apparent ileal amino acid digestibility (AID) of poults (Experiment 1) or chicks (Experiments 2 and 3). Two basal diets were formulated: a nutrient adequate positive control (PC), which met or exceeded the nutrient requirements for poults (Experiment 1) or chicks (Experiments 2 and 3) and a negative control (NC) formulated to achieve 85% (Experiments 1 and 2) or 80% (Experiments 3) of the requirement for protein and amino acids. Phytase was included in all diets to provide 500 phytase units (FTU)/kg and xylanase was included in all diets to provide 10,000 (Experiments 1 and 2) or 16,000 (Experiments 3) xylanase units (BXU)/kg. Proteases were supplemented in the NC diet at an equivalent amount of enzyme protein to create 16 experimental diets. There were five birds/pen and 10 replicate pens per treatment in each experiment. In experiment 1, birds fed the PC diet gained more (P < 0.05) than birds fed the NC. There were no differences in growth performance in birds fed the PC or NC in experiments 2 or 3. In all three experiments, birds fed the NC supplemented with neutral protease 1 had reduced (P < 0.05) feed intake (FI) or body weight gain (BWG) and increased (P < 0.05) feed conversion ratio (FCR) compared with birds fed the NC. Birds fed the NC diet supplemented with neutral protease 3, 7 (Experiment 1), or acid protease 4 (Experiment 3) had increased (P < 0.05) FCR and birds fed neutral protease 6 (Experiment 2) had reduced (P < 0.05) BWG compared with birds fed the NC. Apparent ileal amino acid digestibility was improved (P < 0.05) with protease supplementation to the NC diets (Experiment 1 or 3), but this was dependent on the protease and the amino acid. In conclusion, novel protease supplementation improved AID of amino acids but this was not reflected in improvements in growth performance of poults or chicks. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate phytase supplementation on growth, phytate degradation, and the gene expression of myo-inositol transporters in 21-day old broilers. Ross 308, male broilers (n = 240) were assigned to one of four diets, with 10 pens/diet and six birds/pen from day one to 21. The diets consisted of a negative control (NC) formulated to meet or exceed Ross 308 nutrient requirements, with the exception of calcium (Ca) and available P (avP), which were reduced by 0.16 and 0.15%, respectively. The NC diet was supplemented with 0, 500, 1,500, or 4,500 units/kg of phytase (FTU) to create four experimental diets. On day 21, all birds per pen were euthanized to obtain digesta and tissue samples for phytate degradation and gene expression. Data were analyzed as an analysis of variance using the fit model platform in JMP v 13.0. The model included phytase and significant means were separated using orthogonal linear and quadratic contrasts. Phytase supplementation increased gain (linear, P < 0.05). Phytate (iP6; quadratic, P < 0.05), phytate ester (iP5, iP4, iP3; quadratic, P < 0.05), and inositol (linear, P < 0.05) concentration in the gizzard was influenced by phytase supplementation. Phytate concentration decreased (linear, P < 0.05), iP5 or iP4 concentration increased and then decreased (quadratic, P < 0.05), and inositol concentration increased (quadratic, P< 0.05) in the ileal digesta as phytase supplementation increased in the diet. There was a tendency for the gene expression of the H+-dependent myo-inositol transporter, HMIT, to increase (linear, P < 0.05) in the ileum as phytase dose increased. Gene expression of the sodium-dependent myo-inositol transporter, SMIT2, increased in the jejunum (quadratic, P < 0.05) as phytase dose increased. Intestinal alkaline phosphatase expression increased (linear, P < 0.05) in the ileum as phytase supplementation increased in the diet. The influence of phytase on phytate, phytate esters, and inositol may influence intestinal alkaline phosphatase activity and the gene expression of myo-inositol transporters in the small intestine. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate how the addition of microbial phytase influenced growth performance, bone mineralization, tissue P content, apparent digestibility and retention, and inositol phosphate (IP) concentrations in broilers fed diets with varying mineral matrices from 2 to 23 d of age. At 2 d of age, chicks were randomly allotted to receive 1 of 6 experimental diets arranged as a 3 x 2 factorial of mineral matrix [control diet with 1.0% Ca and 0.5% non-phytate phosphorus (NPP); mineral matrix 1 with 0.84% Ca and 0.35% NPP; and mineral matrix 2 with 0.77% Ca and 0.29% NPP] and phytase supplementation (0 or 1,500 FTU/kg). Feed intake was influenced (quadratic, P = 0.012) by the mineral matrix, but no interaction or main effect of phytase were observed. Phytase increased (P = 0.011) BW gain regardless of the mineral matrix applied. Feed efficiency was not influenced (P > 0.05) by mineral matrix, phytase, or their interaction. Phytase increased bone ash content differentially across matrices (interaction, P < 0.01), and tibia P content was lowest in birds fed matrix 2 and highest in the control (linear, P < 0.05). Concentrations of P in muscle, spleen, and liver were not affected by treatment. An interactive effect (P < 0.01) was observed for apparent ileal digestibility (AID) of P, where phytase increased AID in matrix 1. An interactive effect (P < 0.01) was observed for apparent retention of P and Ca, where phytase reduced P and Ca retention in the control diet. A main effect (P < 0.01) of mineral matrix was observed for AID of Ca, with birds fed matrix 1 having the lowest AID of Ca compared with control and matrix 2 treatments. Phytase influenced (P < 0.05) IP concentrations differently across matrices. Overall, phytase and the mineral matrix, either as main effects or in an interactive manner, influenced growth performance, apparent nutrient digestibility and retention, bone and IP concentration responses in broiler chicks. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the influence of dietary Ca concentrations (Experiment 1) and a combination of dietary Ca and non-phytate phosphorus (NPP) to create distinct Ca-to-NPP ratios (Experiment 2) in corn-soybean meal diets fed to broiler chickens from 2 to 23 d of age. In Experiment 1, dietary treatments consisted of 7 concentrations of Ca (0.4, 0.6, 0.8, 1.0, 1.2, 1.4, or 1.6% of the diet; 7 treatments total), and NPP concentrations were maintained at 0.3%. Increasing the dietary Ca concentration while maintaining 0.3% NPP elicited linear reductions (P < 0.01) in overall growth performance and tibia ash. Dietary effects also were observed for apparent retention of P and Ca, which decreased (P < 0.05) linearly or quadratically for birds receiving dietary treatments with Ca concentrations greater than 0.6%. In Experiment 2, diets were formulated to contain 3 concentrations of Ca (0.4, 1.0, or 1.6% of the diet) with NPP concentrations either constant at 0.45% or adjusted to maintain a dietary Ca-to-NPP ratio of 2:1 (6 treatments total). Growth performance was not influenced by Ca concentration or the Ca-to-NPP ratio. Tibia break force was lower (P < 0.01) in birds fed diets containing 0.4% Ca, regardless of the NPP concentration. Tibia ash increased (P < 0.01) as the dietary Ca concentration increased. Neither the dietary Ca nor NPP concentrations affected nitrogen retention (P > 0.05). Upon maintaining a constant 2:1 Ca-to-NPP ratio, P and Ca retention decreased (P < 0.01) at the highest Ca concentration. In conclusion, imbalanced Ca and NPP adversely influenced growth performance and nutrient retention of broilers, indicating the concentrations of Ca and NPP required to maximize bone structure and function may be higher than those required for performance. [ABSTRACT FROM AUTHOR]

The aim of the study was to observe the effects of dietary available phosphorus (aP) and calcium (Ca), with regular or super doses of phytase, on phytate hydrolysis and subsequent influences on broiler growth performance and nutrient utilization. In a 2 × 3 factorial design, 384 Ross-308 broilers were allocated to one of 6 dietary treatments with 8 replicates in a randomized complete block design for 21 days. Diets were nutritionally adequate (positive control, PC) or marginally deficient in aP and Ca (negative control, NC), with 0, 500 or 1,500 FTU/kg phytase. Bird and feed weights were recorded on d 0 and 21, excreta were collected on d 19 and 20, and gizzard and ileal contents were collected on d 21. Body weight gain (P < 0.01) increased linearly with phytase in the PC and quadratically in the NC. There was an interactive effect on ileal DM, N, and P utilization, increasing quadratically with phytase supplementation in the NC, but there was no phytase influence in the PC (P < 0.05). Phytase linearly increased copper (P < 0.001) and linearly decreased Ca (P < 0.05) utilization in the ileum. Phytase decreased ileal (IPx, inositol x-phosphate) IP6 and IP5 and increased inositol (quadratic, P < 0.001) but had no effect on IP4 or IP3. The influence of the dietary aP was more apparent on the hydrolysis of phytate and phytate esters after the ileum, with increasing (linear and quadratic, P < 0.05) IP4 and IP3 content in the excreta of birds fed the NC or PC when phytase was added. Phytate hydrolysis improves the growth potential of birds fed NC diets, allowing them to match the growth performance of birds fed PC diets and improve nutrient utilization. These results indicate that dietary Ca and aP concentrations can be reduced when phytase is supplemented. It also may be beneficial to apply the enzyme nutrient matrix to other nutrients in the diet to maintain an optimal balance of nutrients in the digesta. [ABSTRACT FROM AUTHOR]