Nonphytate Phosphorus Requirement Research Articles

Assessment of Non-Phytate Phosphorus Requirements of Chinese Jing Tint 6 Layer Chicks from Hatch to Day 42

We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn–soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1–14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15–42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1–14 and 15–42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1–14 and 15–42 d birds, respectively, to optimize P utilization without affecting performance.

Dietary non-phytate phosphorus requirements for optimal productive and reproductive performance, and egg and tibial quality in egg-type duck breeders

Optimal dietary non-phytate phosphorus (NPP) is essential in poultry to maximise productive and reproductive performance, along with indices of egg and bone quality. This study aimed to establish the NPP requirements of egg-type duck breeders aged from 54 to 80 weeks on the following traits: egg production, egg incubation, egg quality, tibial characteristics, reproductive organ, plasma indices, and the expression of genes related to phosphorus absorption. Longyan duck breeders aged 54 weeks (n = 300) were randomly allotted to five treatments, each containing six replicates of 10 individually caged birds. Birds were fed corn-soybean meal-based diets containing 0.18, 0.25, 0.32, 0.38, and 0.45% NPP/kg for 27 weeks. The tested dietary NPP levels did not affect egg production or egg quality indices. The hatchling weight of ducklings increased (quadratic, P < 0.01) as dietary NPP level increased, and the highest value occurred with 0.25% NPP. The number of large yellow follicles (LYF), and the relative weights of LYF and ovary showed linear and quadratic responses to dietary NPP levels; the lowest number and relative weight of LYF occurred with 0.38% NPP, and the lowest ovarian weight was obtained with 0.25% NPP. There were no differences in tibial length, breaking strength, and mineral density in response to dietary NPP levels. In contrast, tibial content of Ca increased (linear, P < 0.01) with dietary NPP levels increasing from 0.18 to 0.45%, and the tibial content of P increased at 0.32% NPP and the higher dietary NPP levels. Plasma concentration of P showed a quadratic (P < 0.05) response to the dietary NPP levels, where the highest value was seen at 0.38% NPP. In conclusion, dietary NPP levels from 0.18 to 0.45% had no effects on egg production, and egg and tibial quality of duck breeders. The duck breeders fed a diet with 0.25% NPP showed the highest hatchling weight of their offspring, while those fed 0.38% NPP had the lowest number and relative weight of LYF. These results indicated that the diet with 0.25% NPP can be used in egg-type duck breeders to improve the hatchling weight of their offspring, without adverse effects on their productivity. The regression model indicated that the maximal hatchling weight of ducklings was obtained from duck breeders fed the diet with 0.30% NPP.

Minimum phosphorus requirements for laying hen feed formulations

The objective of this contribution was to summarize from scientific literature the optimal concentration of nonphytate phosphorus (NPP) in feed for laying hens. The considered studies were one meta-analysis from 2012 and original studies published since then. Dietary treatments in the studies included variation in supplementation with mineral P sources and phytase. The studies investigated different periods of production and varied in duration but data were insufficient to analyze such factors in a systematic way. No study showed a positive effect on performance and eggshell when the NPP concentration was increased above 2.2 g NPP/kg of feed without the use of phytase. At such level, no consistent impairment of various bone quality traits were found but only few studies on bone quality traits were published. Overall, the data suggested that not more than 2.2 g NPP/kg of feed is needed for laying hens in different stages of production. This value can be reduced when phytase is added to the feed. Such reduction may differ depending on factors such as phytate content of the feed and phytase dosage. However, data are insufficient for calculating precise values of reduction. While phytate degradation in laying hens was markedly increased by phytase supplementation in several studies, effects of phytase supplementation on performance and bone traits in laying hens were less conclusive probably because the hens were supplied more than their NPP requirement. Transition to a system based on digestible P for laying hens similar to broiler chickens may support more precise P nutrition and more sustainable egg production in the future.

Determination of non-phytate phosphorus requirement for slow-growing feather-frizzled broilers from 1 to 21 days of age

The influence of dietary non-phytate phosphorous (NPP) on growth performance, carcass characteristics, bone quality and serum parameters were investigated to determine the NPP requirement of slow-growing feather-frizzled broilers aged from 1 to 21 days. A total of 480 1-day-old indigenous slow-growing male feather-frizzled broilers were assigned to 1 of 6 treatments with 8 cage replicates of 10 birds each using a completely randomized design. They were fed with corn-soybean meal-based basal diet (containing 0.13 % of NPP) supplemented with 0.00 %, 0.08 %, 0.16 %, 0.24 %, 0.32 %, and 0.40 % of inorganic phosphorus (CaHPO4.2 H2O), respectively. The experimental diets contained a constant 0.90% calcium. Results showed that body weight gain, feed intake, eviscerated carcass ratio, tibia breaking strength, tibia and toe ash or phosphorous concentrations, femoral strength and serum inorganic phosphorous concentration were affected (P < 0.010) by dietary NPP level, and showed significant quadratic responses (P < 0.030) to dietary NPP levels. The estimates of dietary NPP requirements were 0.25–0.36 % based on the best fitted broken-line or quadratic models (P < 0.029) of the above performance, serum and bone parameters. In conclusion, the NPP requirements would be about 0.25 % to obtain the optimum growth performance and carcass yield, and 0.36 % to meet bone development and P metabolism for such slow-growing feather-frizzled broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.

Requirement of Non-Phytate Phosphorus in 1- to 28-Day-Old Geese Based on Growth Performance, Serum Variables, and Bone Characteristics

The standard of dietary non-phytate phosphorus (NPP) requirement is important for geese production. However, limited reports remain an obstacle to the NPP requirement of geese. We aimed to evaluate the NPP requirement in geese based on the effects of NPP levels on growth performance, serum variables, and bone characteristics in 1–28-day-old geese. One-day-old male Jiangnan White Geese (n = 360) were randomly divided into five groups. Five corn-soybean diets were used in these groups, with NPP levels at 0.18%, 0.28%, 0.39%, 0.47%, 0.59% in the feed, respectively. The average body weight, serum phosphorus (P) content, tibia strength, tibia P content, and femoral skim weight were significantly reduced, by 0.18%, compared with 0.28–0.59%. These variables had significant linear fit (p &lt; 0.001) between the levels of 0.18% and 0.58%. The estimated requirement of NPP for goslings is between 0.28% and 0.35%, based on the broken-line model, using the above indicators. In conclusion, the dietary NPP requirement for 1–28-day-old geese should be no less than 0.35% to ensure normal growth performance and bone development, based on body weight gain, serum P content, and skeletal variables.

Non-phytate phosphorus requirements of egg laying pullets from 0 to 3 weeks of age and carryover effects of phosphorus deficiency at 6, 9, 12, and 18 weeks of age

The objectives were to determine the non-phytate phosphorus ( nPP ) requirement in 0 to 3-wk-old laying hen pullets using body weight ( BW ), mortality corrected feed conversion ratio ( FCRm ), tibia ash expressed as weight ( TAW ) and percentage ( TAP ), and total body bone mineral content ( BMC ) and to understand the longer term effects of early phosphorus deficiency on pullets over time. Hy-Line W36 pullets were distributed across 42 cages resulting in 7 dietary treatments (0.15, 0.22, 0.29, 0.36, 0.43, 0.49, and 0.53% nPP and 1.0% Calcium) fed across 6 replicate cages of 30 chicks. After 3 wk, all birds were switched to common corn-soybean meal diets that contained 0.49, 0.48, 0.45, 0.48% nPP and 1.0, 1.0, 1.0, 2.5% Ca from 3–6, 6-12, 12–15, 15–18, respectively. Pullets were euthanized at 3, 6, 9, 12, and 18 wk of age for BMC and tibia ash determination. Linear and quadratic broken-lines were used to estimate nPP requirements of 0 to 3-wk-old pullets. The nPP requirement was 0.31% nPP for BW; 0.27% nPP for FCRm; 0.31% for TAP; 0.31% for TAW; 0.32% for BMC using linear broken line analysis. Low concentrations of dietary nPP fed over the 0 to 3 wk period reduced BW at 6 wk ( P ≤ 0.05), but after 9 wk no response criteria were different among the dietary nPP treatments ( P > 0.05). These data indicate that the nPP requirement for pullets from 0 to 3 wk is between 0.27 and 0.32% nPP dependent on response criteria used, and that there are few to no long-term effects of low phosphorus feeding when pullets are provided an adequate nPP diet over time.

Response of modern broiler chickens to dietary calcium and phosphorus levels below recommendations

This study was carried out to investigate the effects of reduced dietary calcium (Ca) and non-phytate-phosphorus (NPP) levels on performance, carcase yield and bone mineralisation of modern broilers. 11,200 one-day-old chicks (Ross-308) were divided into 7 treatments and 8 replicates with standard recommended level and six different levels of Ca and NPP reduction with completely randomised block design. Treatments were divided into following diets; T1: ross recommended control, T2: 94%, 95% and 91% as percentage of T1, T3: 94%, 95% and 83% as percentage of T1, T4: 94%, 91% and 83% as percentage of T1, T5: 94%, 91% and 77% as percentage of T1, T6: 94%, 86% and 83% as percentage of T1 and T7: 94%, 86% and 77% as percentage of T1 for starter, grower and finisher periods, respectively. Results showed that, the Ca and NPP reduction (T2–T7) through starter period did not significantly (p>.05) affect performance but when considered whole period, quadratically (p<.05) improved body weight gain (BWG), feed conversion ratio (FCR) and European Production Efficiency (EPEF). In line with, Ca and NPP intakes were decrease linearly and quadratically with Ca and NPP reducing in diet and higher intakes at T1 resulted in impaired BWG and FCR. On the other hand, carcase parameters and tibia mineralisation were not significantly affected by the reductions. In conclusion, Ca and NPP requirements of Ross 308 broilers seem to be lower than the Aviagen 2014 and 2019 recommendations and reducing almost 20% Ca and NPP intake of broilers is possible, especially after starter period, to maintain performance without any negative effect on bone development. Highlights Excessive dietary Ca and P feeding have potential deleterious effects on broilers. Dietary Ca and NPP reduction improved growth performance, without impairment bone characteristics. Especially after starter period, Ca and NPP reduction, by keeping the dietary levels as 0.90:0.45, 0.75;0.38 and 0.60;0.30% for starter, grower and finisher phase respectively, seems enough for Ross-308.

Modelling and optimizing of calcium and non-phytate phosphorus requirements of male broiler chickens from 1 to 21 days of age using response surface methodology

The skeleton is the main site of P and Ca deposition; therefore, accurate estimation of Ca and P requirements is necessary to maintaining health and optimum performance of broiler chickens. A response surface methodology (RSM) using a central composite design (CCD) was used for evaluating and optimizing of Ca and non-phytate P (NPP) requirements of broiler chickens for optimal performance, ileal nutrient digestibility and bone mineralization from 1 to 21 days of age. A total of 750 one-day-old male broiler chickens (Ross 308) were randomly distributed into 50 cages including 9 treatments, each replicated 5 times (except central treatment with 10 replicates) and 15 birds in each cage by CCD. The dietary Ca levels of 4.3, 5.6, 8.6, 11.7 and 13.0 g/kg and NPP of 2.5, 2.9, 4.0, 5.0 and 5.4 g/kg were used for nine treatments of CCD. The results indicated that the linear and quadratic effects of NPP, quadratic effects of Ca and Ca × NPP were significant for average weight gain (AWG, P < 0.05), average feed intake (AFI, P < 0.05), feed conversion ratio (FCR, P < 0.05) and Ca and P apparent ileal digestibility (AID, P < 0.05); however, the linear effect of Ca was significant only for FCR (P < 0.05). On the other hand, tibia and toe ash were affected by NPP (linear and quadratic, P < 0.01) and Ca (quadratic, P < 0.01). The second-order polynomial regression model was significant for AWG (R2 = 0.93, P < 0.001), AFI (R2 = 0.88, P < 0.001), FCR (R2 = 0.78, P < 0.001), AID of Ca (R2 = 0.78, P < 0.001) and P (R2 = 0.88, P < 0.001), tibia ash (R2 = 0.86, P < 0.001) and toe ash (R2 = 0.85, P < 0.001). The multi-objective optimization indicated that broiler chickens from 1 to 21 days of age need 7.03 and 4.47 g/kg of Ca and NPP, respectively, to achieve optimal AWG, FCR, tibia and toe ash. However, the dietary Ca and NPP levels can be reduced to 6.57 and 3.95 g/kg with a slight negative impact on performance and bone mineralization, respectively. In conclusion, the findings indicate that using multi-objective optimization model such as RSM provides more information regarding optimum Ca and NPP requirements of broiler chickens, considering the complex interaction between these two minerals. While the NPP levels are in line with current recommended requirements, Ca levels are considerably lower and suggest that current recommended Ca requirements may be in excess of the needs of the broiler.

Non-phytate phosphorus requirement for male broilers subjected to two calcium supply regimens from 8 to 21 days of age under thermoneutral environment conditions

The purpose of this study was to determine the non-phytate phosphorus (nPP) requirement for male broiler subjected to two calcium supply regimens from 8 to 21 d of age, based on performance and bone mineralization. Birds were distributed in a complete randomized 4 × 2 factorial design with four nPP concentrations: 0.25, 0.35, 0.45 and 0.55%, and two Ca supply regimens: Ca fixed at 9.0 g/kg of diet (CaF) or varying together with the nPP concentrations tested keeping a fixed Ca:nPP ratio (CaV), with 8 battery cages/treatment and 9 birds/battery cage. Feed intake (FI), body weight gain (BWG) and Ca:P ratio deposited in the dry defatted tibia (TibCa:TibP) were quadraticaly increased by the increasing nPP concentrations, regardless of the Ca supply regimen adopted (p&lt;0.01). The nPP levels tested also influenced FCR and TibAsh, which presented a quadratic and linear response when CaF and CaV diets were used, respectively, and TibP and TibCa, which presented a quadratic response with both Ca supply regimen, CaF and CaV diets. Also, CaV diets provided a 2.86 and 5.02% higher FCR (p&lt;0.05) and TibCa (p&lt;0.01), respectively, when compared to CaF diets. Therefore, nPP nutritional requirement for male broilers reared at thermoneutral conditions from 8 to 21 d of age that provided better performance and bone mineralization were, respectively, 0.480 and 0.459% with CaF and 0.550% with CaV diets, indicating that, under thermoneutral conditions, CaV diets negatively affected growth performance of broilers, while positively affecting bone mineralization especially when low nPP levels are applied.

THE EFFECTS OF PHYTASE SUPPLEMENTATIONS IN PREDICTING THE NON-PHYTATE PHOSPHORUS REQUIREMENT OF BROILERS IN STARTER PHASE

This study was aimed to observe the requirements of non-phytate phosphorus (NPP) with phytase supplementation in starter phase broiler. A total number of 1000 broiler (500 males and 500 females) were divided into 5 dietary treatments for 21 days rearing period. The treatment diets (P1-P5) were basal diets with 0.67% Calcium (Ca) and 60 FTU phytase that combined with NPP at different levels, i.e.: 0.420% (P1); 0.345% (P2); 0.270% (P3); 0.195% (P4); 0.120% (P5). The basal diet was a corn-soybean based diet that contained 0.097% Ca and 0.124% Phosphorus (P). The data were subjected to a one-way ANOVA using complete randomized design. Response variables that observed in current study were: feed intake, nett gain, feed convertion ratio, average body weight, mortality and toe ash. Measurement of responses due to the reduction of NPP supplementation on average body weight and toe ash were then followed subsequently by generating equation for quadratic curve y = ax2+bx+c to determinate the NPP requirement. Determination of the maximum response was done through ymaks = -b/2a. Results showed that based on average body weight, estimation of NPP requirement with phytase supplementation were 0.317% for the 0-10 days; 0.314% for the 11-21 days; and 0.315% for the the 0-21 days rearing periods. Based on toe ash content, estimation of NPP requirement with phytase supplementation was 0.990% (toe) for the 21 days rearing period. This study was aimed to observe the requirements of non-phytate phosphorus (NPP) with phytase supplementation in starter phase broiler. A total number of 1000 broiler (500 males and 500 females) were divided into 5 dietary treatments for 21 days rearing period. The treatment diets (P1-P5) were basal diets with 0.67% Calcium (Ca) and 60 FTU phytase that combined with NPP at different levels, i.e.: 0.420% (P1); 0.345% (P2); 0.270% (P3); 0.195% (P4); 0.120% (P5). The basal diet was a corn-soybean based diet that contained 0.097% Ca and 0.124% Phosphorus (P). The data were subjected to a one-way ANOVA using complete randomized design. Response variables that observed in current study were: feed intake, nett gain, feed convertion ratio, average body weight, mortality and toe ash. Measurement of responses due to the reduction of NPP supplementation on average body weight and toe ash were then followed subsequently by generating equation for quadratic curve y = ax2+bx+c to determinate the NPP requirement. Determination of the maximum response was done through ymaks = -b/2a. Results showed that based on average body weight, estimation of NPP requirement with phytase supplementation were 0.317% for the 0-10 days; 0.314% for the 11-21 days; and 0.315% for the the 0-21 days rearing periods. Based on toe ash content, estimation of NPP requirement with phytase supplementation was 0.990% (toe) for the 21 days rearing period.

Dietary non-phytate phosphorus requirement of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age

An experiment was conducted to investigate the effect of dietary non-phytate phosphorus (NPP) level on growth performance, bone characteristics and phosphorus metabolism-related gene expressions, so as to evaluate the dietary NPP requirement of broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age. A total of 540 day-old Arbor Acres male chicks were randomly allocated to one of nine treatments with six replicate cages of 10 birds per cage in a completely randomized design, and fed a basal corn-soybean meal diet (containing 0.08% of NPP) supplemented with 0.10, 0.15, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50% of inorganic phosphorus in the form of CaHPO4·2H2 O, respectively. Each diet contained the constant calcium content of about 1.0%. The results showed that daily weight gain, serum inorganic P, tibia bone strength, tibia ash percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage, middle toe BMC and BMD were affected (P < 0.0001) by dietary NPP level, and increased linearly (P < 0.0001) and quadraticly (P < 0.004) as dietary NPP levels increased. The gene expression of type IIb sodium-phosphate cotransporter (NaPi-IIb) in the duodenum was affected (P < 0.03) and decreased linearly (P < 0.002) as dietary NPP levels increased. Dietary NPP requirements estimated based on fitted broken-line models (P < 0.0001) of the sensitive indices including daily weight gain, tibia bone strength, tibia ash percentage, tibia BMC and BMD as well as middle toe ash percentage were 0.34∼0.39%. The results from this study indicate that tibia BMC and BMD might be new, sensitive, and noninvasive criteria to evaluate the dietary NPP requirements of broilers, and the dietary NPP requirement is 0.39% for broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age.

An optimal dietary non-phytate phosphorus level of broilers fed a conventional corn–soybean meal diet from 4 to 6 weeks of age

It is imperative to evaluate precise nutrient requirements of animals in order to optimize productivity and minimize feed cost and nutrient excretions. The current non-phytate phosphorus (NPP) recommendation for broilers is based on the papers published 30 years ago. However, today’s commercial birds are quite different from those before 30 years. Therefore, the present experiment was conducted with growing male broiler chickens to evaluate an optimal dietary NPP level of broiler chickens fed a conventional corn–soybean meal diet from 4 to 6 weeks of age. The 1-day-old chicks were fed corn–soybean meal diet containing 0.39% NPP from 1 to 3 weeks of age. At 22 days of age, 360 birds were selected and randomly allotted by BW to one of 10 dietary treatments with six replicate cages of six birds per cage for each treatment. Birds were fed the P-unsupplemented corn–soybean meal basal diet and the basal diet supplemented with inorganic P as CaHPO4·H2O ranging from 0.00% to 0.45% with 0.05% increment from 4 to 6 weeks of age. The dietary NPP levels were 0.09%, 0.14%, 0.20%, 0.24%, 0.30%, 0.34%, 0.38%, 0.45%, 0.49% and 0.54%, respectively, and the dietary Ca level was fixed at 0.90% for all treatments. The results showed that average daily gain, serum inorganic P concentration, tibia bone strength, tibia ash percentage and P percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage and P percentage, middle toe BMC, total body BMC and BMD were affected (P<0.0001) by dietary NPP level, and increased linearly (P<0.0001) and quadratically (P<0.003) as dietary NPP levels increased. Optimal dietary NPP levels estimated based on fitted broken-line models (P<0.0001) of the above indices are 0.21%, 0.29%, 0.29%, 0.29%, 0.29%, 0.31%, 0.29%, 0.30%, 0.27%, 0.29% and 0.28%, respectively. It is suggested that the total body BMC and BMD, and middle toe ash P and BMC might be new, sensitive and non-invasive criteria to evaluate the dietary NPP requirements of broilers. The optimal dietary NPP level would be 0.31% for broiler chickens fed a conventional corn–soybean meal diet from 4 to 6 weeks of age.

Nonphytate Phosphorus Requirement and Efficacy of a Genetically Engineered Yeast Phytase for Yellow Broilers at 22- to 42-d-Old Age

An experiment was conducted to investigate the requirement of nonphytate phosphorus (nPP) and efficacy of a genetically engineered yeast phytase (PHY A) for Lingnan yellow broilers from 22- to 42-d-old age. A total of 1 320 1-d-old male chicks were randomly divided into 11 dietary treatment groups, which consisted of 4 replicate floor pens with 30 birds per pen. The control group (treatment 1) was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation. Dietary levels of nPP were 0.16, 0.24, 0.32, 0.40, 0.48, and 0.56%, respectively, for treatments 2 to 7, through addition of dicalcium phosphate (chemistry grade) to the basal diet. Diets of treatments 8 to 11 were supplemented with PHY A at 200, 400 and 600 U kg −1, a commercial phytase product (PHY B) at 400 U kg −1 level, respectively. The birds in 0.32–0.56% nPP groups gained more than those of the other groups ( P<0.05). The nPP supplementation significantly improved feed intake ( P<0.05). The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds ( P<0.05). The level of 0.48% nPP was required for optimum tibia development. The additions of PHY A at 400 and 600 U kg- 1 level and PHY B all significantly improved ADG ( P<0.05), ADFI ( P<0.05), and dry defatted tibia weight ( P<0.05). Similarly, the percentage of tibia ash was increased by 600 U kg −1 PHY A supplementation ( P<0.05). The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%. The phosphorus equivalency value of PHY A was estimated as 685 U kg- 1 for male yellow broilers of 22- to 42-d-old age.

Non-phytate phosphorus requirements and efficacy of a genetically engineered yeast phytase in male lingnan yellow broilers from 1 to 21 days of age

This experiment was conducted to investigate the requirement of non-phytate phosphorus (nPP) and efficacy of a genetically engineered yeast phytase in performance and tibia characteristics by male Lingnan Yellow broilers from 1 to 21 days of age. A total of 2640 1-day-old male chicks were randomly allotted to one of 11 dietary treatments, which consisted of six replicate floor pens with 40 birds per pen. All treatments had the same levels of all nutrients except for phosphorus and phytase. The control group (treatment 1) was fed the basal diet without dicalcium phosphate or phytase supplementation. Dietary concentrations of nPP were 0.11%, 0.19%, 0.27%, 0.35%, 0.43%, 0.51% and 0.59% respectively for treatments 1, 2, 3, 4, 5, 6 and 7, through addition of dicalcium phosphate (chemistry grade) to the basal diet. Diets 8-11 were supplemented with a genetically engineered yeast phytase 250, 500, 750 U/kg and a commercial phytase product 500 U/kg in basal diet respectively. The results showed that 0.46% and 0.51% nPP were required for maximum body-weight gain and optimum tibia development indicators respectively. However, 0.59% nPP had a negative effect on bird growth. The equivalency value of the genetically engineered yeast phytase was estimated to be 874 U/kg to liberate 0.1% nPP.

Interaction between dietary calcium and non-phytate phosphorus on growth performance and bone ash in early White Pekin ducklings

A 4 × 5 factorial experiment containing four non-phytate phosphorus (NPP) levels (2.0, 3.0, 4.0, 5.0 g/kg) and five calcium (Ca) levels (4.0, 6.0, 8.0, 10.0, 12.0 g/kg) was conducted to evaluate the interaction between dietary Ca and NPP on growth performance and bone ash in White Pekin ducklings from hatch to 14 days of age. A total of 1280 one-day-old male White Pekin ducklings were assigned to twenty experimental treatments, each containing 4 replicate pens with 16 birds per pen, and these birds were raised with feed and water provided ad libitum. At 14 days of age, weight gain, feed intake, feed/gain and tibia ash of each treatment were measured. In the current study, the interaction between dietary Ca and NPP significantly influenced weight gain, feed intake, feed/gain, and tibia ash but the overall effects of these two minerals on these parameters except tibia ash were not significant. The weight gain, feed intake and tibia ash decreased (P<0.01) as dietary Ca increased from 4.0 to 12.0 g/kg at the lowest NPP level (2.0 g/kg) but these adverse effects could be alleviated or reversed at other dietary NPP from 3.0 to 5.0 g/kg. Considering the significant interaction between dietary Ca and NPP, the quadratic response surface regression analysis was used to predict the Ca and NPP requirements of ducklings. According to this regression analysis, the predicted requirements of Ca and NPP for maximum weight gain and minimum feed/gain were 8.06 and 4.03 g/kg, 7.96 and 3.79 g/kg, respectively.

Utilização de nutrientes em frangos alimentados com dietas suplementadas com fitase e níveis reduzidos de fósforo não-fítico

Avaliaram-se a digestibilidade ileal, retenção de nutrientes e valores de energia metabolizável aparente (EMA) de dietas suplementadas com fitase e níveis reduzidos de fósforo não-fítico (FNF) para frangos de corte. Foram utilizados 330 pintos machos em delineamento em blocos ao acaso e esquema fatorial 2 x 3 com dois níveis de fitase (0 e 25U/kg) e três níveis de FNF (100, 85 e 70% das exigências da ave), totalizando seis tratamentos com cinco repetições de 11 aves cada. Não houve efeito da interação FNF vs fitase e dos níveis de FNF ou fitase sobre a retenção de matéria seca e de fósforo, e a interação FNF vs fitase foi significativa para retenção de proteína bruta e coeficiente de digestibilidade ileal da matéria seca. A suplementação com fitase, independente dos níveis de FNF, melhorou o coeficiente digestibilidade ileal da proteína bruta, do cálcio e do fósforo. A retenção de cálcio e a redução dos níveis de FNF diminuíam a metabolização da energia bruta das dietas com 85 e 70% das exigências de FNF. Dietas com nível de 70% das exigências de FNF, suplementadas com fitase, podem ser usadas para frangos de corte sem prejuízos à digestibilidade ileal e retenção da matéria seca, proteína bruta, cálcio e fósforo e à metabolização da energia bruta.

Nonphytate Phosphorus Requirement and Phosphorus Excretion of Broiler Chicks Fed Diets Composed of Normal or High Available Phosphate Corn as Influenced by Phytase Supplementation and Vitamin D Source

Nonphytate Phosphorus Requirement and Phosphorus Excretion of Broiler Chicks Fed Diets Composed of Normal or High Available Phosphate Corn as Influenced by Phytase Supplementation and Vitamin D Source

Evaluation of Nonuniform Application of Phytase (Simulated) on Growth Performance and Bone Quality in Broiler Chicks

The postpellet application of phytase can be variable and can lead to high coefficients of variation (CV). Two trials were conducted to evaluate the effects of high CV of phytase application (simulated by feeding 2 to 4 times the recommended level of phytase fed every second, third, or fourth day), when added to a standard broiler diet deficient in nonphytate phosphorus (NPP) and fed to 0- to 21-d-old male broilers. A standard curve of graded levels of NPP was included in both trials to determine the NPP requirement. Weight gain, feed efficiency, tibia breaking strength, and percentage tibia ash were assessed in both trials. Trial 1 was designed to evaluate the effect of a high variation (103% CV; 23,000 phytase units (PTU)/kg fed every other day) of added phytase fed on alternate days compared with low variation of added phytase fed daily (0% CV; 11,500 PTU/kg fed daily) and to determine the optimal phytase inclusion level and the NPP requirement. Trial 2 was conducted to determine the maximum variation of phytase addition fed alternate days and reevaluate the NPP requirement. When tibia ash was used as the response criterion, the NPP requirement was determined to be 0.42% in both experiments, and the optimal phytase level was determined to be 14,630 PTU/kg feed. The results of these studies also suggest that feeding a high variation diet of added phytase (103% CV) was not detrimental to the parameters evaluated. Only when the CV exceeded 103% was bone quality negatively affected.

Phosphorus requirements of broiler chicks six to nine weeks of age as influenced by phytase supplementation

Two trials of similar design were conducted to determine the nonphytate phosphorus (NPP) requirements for broilers from 42 to 63 d of age in diets with or without phytase supplementation. Male broilers of a commercial strain were grown to 42 d on nutritionally complete diets with NRC (1994) recommended levels of Ca and NPP. At 42 d, the birds were placed on experimental diets and fed to 63 d. The experimental treatments consisted of a 2 x 6 factorial arrangement with two levels of phytase (0 or 800 U/kg) and six levels of NPP (0.10 to 0.35% in 0.05% increments). Body weight gain, feed conversion, and mortality were determined during the period. At 49, 56, and 63 d, excreta samples were taken, and samples of birds were killed for tibia ash determination. The lowest level of NPP, with or without phytase supplementation, was sufficient for maximum BW gain, feed conversion, and livability. Using nonlinear regression, levels of NPP needed to optimize tibia ash in the absence of phytase were 0.31 +/- 0.004%, 0.23 +/- 0.02%, and 0.22 +/- 0.029% at 49, 56, and 63 d, respectively. When diets were supplemented with 800 U/kg of phytase, the NPP requirement for optimum tibia ash was 0.15 +/- 0.049% at 49 d. At 56 and 63 d, no more than 0.10% NPP (lowest level tested) was sufficient to maximize tibia ash. Compared to current NRC (1994) recommendations, the application of these reduced dietary phosphorus levels could markedly reduce excreta excretion of phosphorus by broilers.

The effect of different levels of nonphytate phosphorus with and without phytase on the performance of four strains of laying hens

A 4 x 7 factorial experiment was conducted to determine the effect of different nonphytate phosphorus (NPP) regimens with and without phytase on performance of four strains of laying hens. The strains used were Babcock B300, DeKalb Delta White, Hy-Line W36, and ISA-White. The birds of T1 (Treatment 1), control diet, were fed a diet with 0.45% NPP for the entire experiment (20 to 63 wk of age). The birds of T2 were fed a NPP regimen of 0.25% for Phase 1 (20 to 35 wk of age), 0.2% for Phase 2 (36 to 51 wk of age), and 0.15% for Phase 3 (52 to 63 wk of age). The birds of T3 and T4 were fed a NPP regimen similar to T2 plus 150 or 300 units phytase/kg diet, respectively. The birds of T5 were fed a NPP regimen of 0.2, 0.1, and 0.1% for Phases 1, 2, and 3, respectively. The birds on T6 and T7 were fed a NPP regimen similar to T5, with 150 and 300 units phytase/kg diet, respectively. The criteria for evaluating the effect of dietary treatments were production performance, shell quality, bone ash, and total P excretion. Production traits were drastically reduced and mortality was drastically increased when the birds of T5 were fed a diet with 0.1% NPP during Phase 2 (36 to 51 wk of age). Increasing the NPP level of this treatment from 0.1 to 0.45% during Phase 3 restored the production traits almost to the control level during this phase of the experiment. The NPP regimen of 0.2-0.1-0.1% plus either level of phytase (T6 and T7) restored most of the traits for the entire experiment to the control level (T1), except egg production (EP) and the nonprolapse mortality. Bone ash also remained significantly lower than the control group with this NPP regimen plus the higher level of phytase (T7). Production traits were reduced, and nonprolapse mortality was increased due to the use of a NPP regimen of 0.25-0.2-0.15% without phytase (T2) for the entire experiment. The NPP regimen of 0.25-0.2-0.15% plus the lower level of phytase (T3) restored all the traits except EP to the control level for the entire experiment. The only treatment that maintained performance of all the strains comparable to their controls for the entire experiment was a NPP regimen of 0.25-0.2-0.15% plus the higher level of phytase (T4). Total P excretion of birds fed this NPP regimen was reduced by 55.6% as compared to the control group. The data generally indicated that the higher level of phytase was more effective than the lower level in restoring the performance of birds fed the low-P diets to the control level. Numerous interactions existed among strain x diet for various traits throughout the experiment, indicating the NPP requirement for maintaining production performance may be different among strains.