Dietary Levels Of Available Phosphorus Research Articles

Effect of 25-hydroxycholecalciferol supplementation with different dietary available phosphorus levels for broilers

ABSTRACT 1. Based on the hypothesis that 25-hydroxycholecalciferol (25-OH-D3) inclusion would optimise dietary mineral digestibility and ameliorate growth performance and bone mineralisation in available phosphorus (AvP) deficient-fed broilers, a trial was conducted to evaluate its effect on diets with different levels of AvP. 2. Broilers aged 1–21 d were randomly assigned one of the eight treatments, consisting of four dietary levels of AvP (0.45%, 0.42%, 0.39%, and 0.36%) and with or without supplementation with 25-OH-D3 at 69 μg/kg of feed. All diets contained 100 µg/kg of vitamin D3 (cholecalciferol). 3. The addition of 25-OH-D3 resulted in higher feed intake and body weight gain, and lower FCR (P < 0.05) compared to non-supplemented diets, whereas AvP levels had a quadratic effect only on feed intake. There were no interactions between treatment factors. 4. Increasing AvP levels linearly reduced the ileal digestibility of Ca and P (P < 0.01) and supplementing 25-OH-D3 increased both Ca and P ileal digestibility (P < 0.05), without any interactions observed for ileal digestibility. 5. There was an interaction, whereby 25-OH-D3 inclusion increased serum metabolites in broilers fed 0.36% to 0.42% AvP compared to the non-supplemented diets (P < 0.001), whereas, at 0.45% AvP, diets with or without 25-OH-D3 had similar results. 6. The P content in bone linearly increased in line with AvP levels (P < 0.05) and supplementation of 25-OH-D3 increased ash bone content (P < 0.001). 7. Broilers can benefit from 25-OH-D3 supplementation combined with cholecalciferol with regard to Ca and P utilisation and vitamin D status, allowing for a reduction of dietary AvP levels down to 0.36% without impairing growth performance or bone status.

A new approach for quantifying phosphorus requirement in Colossoma macropomum using CT scanning

Available phosphorus (AP) requirement for tambaqui (Colossoma macropomum) was evaluated using different response parameters, and CT scanning was used to determine the adequacy of dietary P along with bone mineralization data. A total of 192 tambaqui juveniles (17 ± 0.85 g) were stocked into 24 70 L-tanks using randomized block design (different floors) with six treatments (1.3, 2.4, 4.8, 6.3, 7.8 and 8.8 g kg−1 AP) and four replicates. Fish were fed ad libitum with six semi-purified diets containing graded levels of AP for 90 days. The dietary AP requirement was estimated using non-linear regression models. No mortality or apparent signs of P deficiency were observed. Increasing dietary AP levels improved all performance variables. Dietary P levels significantly affected bone density. The estimated P requirement for tambaqui was 6.3, 3.68, 5.0 and 6.91 g kg−1 diet for improved weight gain, bone density, vertebrae mineralization and carcass mineral deposition, respectively. CT scanning allowed the visualization of bone structures affected by P deficiency and could predict the P requirement based on vertebrae mineralization. Additionally, blood chemistry parameters were significantly affected by the dietary P level, except for serum calcium. Thus, the use of 6.3 g kg−1 AP in tambaqui diets can maintain normal growth and bone mineralization of juveniles from 17–150 g.

Available phosphorus as a reproductive performance enhancer for female Nile tilapia

This study was conducted to evaluate the effects of dietary available phosphorus (AP) on reproductive performance and bone mineralization of Nile tilapia (Oreochromis niloticus) female broodfish. Four isonitrogenous (35% crude protein), isocaloric (18MJ crude energy) diets were formulated to contain 1.1, 2.8, 4.9, and 6.7gkg−1 AP. The diets were fed to four groups of adult Nile tilapia (176.9±2.6g average body weight), 3 males and 9 females per aquarium, at 1% of their biomass for 26weeks. Spawning performance, including spawning frequency (SF), total eggs spawned per fish (TEF), inter spawning intervals (ISI), absolute fecundity (AF), and relative fecundity (RF) significantly improved with increasing dietary AP up to 6.7gkg−1. Based on the polynomial regression analysis of the SF, AF, and RF, the optimum dietary supplementation level of AP was determined to be 6.1, 6.5, and 6.1gkg−1 diet, respectively. Eggs produced from broodstock fed 6.7gkg−1 AP exhibited significantly higher hatchability than at other dietary AP levels. However, there were no differences in weight, diameter, and calcium and phosphorus composition of eggs produced by tilapia fed the experimental diets (P>0.05). Bone volume and densitometry also significantly improved with increasing dietary AP up to 6.7gkg−1. In conclusion, Nile tilapia were responsive to dietary available phosphorus supplementation with fish fed 6.5gkg−1 AP showing significantly enhanced spawning performance and bone mineralization.

Effect of low levels of dietary available phosphorus on phosphorus utilization, bone mineralization, phosphorus transporter mRNA expression and performance in growing pigs

ABSTRACTA study was conducted to examine the effects of different dietary levels of available phosphorus (aP) on P excretion, bone mineralization, performance and the mRNA expression of sodium-dependent P transporters in growing pigs. Sixty-day old growing pigs (n = 54) with an average initial BW of 19.50 ± 1.11 kg were randomly allocated to a control diet (C) containing 0.23% available phosphorus (aP), T1 containing 0.17% aP and T2 containing 0.11% aP. There were 6 pens per treatment with 3 pigs per pen. Body weight and feed intake were measured weekly. At the end of each week, one pig from each pen was housed in a metabolic crate for 24 h to collect fecal and urine samples and then sacrificed to obtain third metacarpal (MC3) bones and jejunal and kidney samples. Bones were scanned by Dual Energy X-ray Absorptiometry (DEXA). Fecal and urine samples were sub-sampled and analyzed for P content. The expression of P transporter mRNA in jejunum and kidney samples was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Data were analyzed using GLM procedure of the Statistical Analysis System (SAS Institute version 9.2). Pigs fed the T2 diet had reduced (P < 0.05) average daily gain (ADG) and gain to feed (G:F) compared to those fed the C diet during week 2. Overall, ADG and G:F were also reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C and T1 diets. Bone mineral density (BMD) and bone mineral content (BMC) were reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet throughout the experiment. At week 1, jejunal mRNA expression of Na (+)-dependent phosphate transporter 2 (SLC34A2) was increased (P < 0.01) in pigs fed the T2 diet compared to C diet. Renal mRNA expression of Na(+)-dependent phosphate transporter 1 (SLC34A1) and SLC34A3 were increased (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet at week 2 and was accompanied by lower (P < 0.05) urinary P in pigs fed the T2 diet during week 2 and week 3. In conclusion, growing pigs are highly sensitive to low dietary P as shown by reduced ADG, bone mineralization and urinary P level, but moderate reduction in dietary P up to 0.17% aP in the diet has the potential to reduce environmental pollution by reducing P concentration in swine manure and without compromising performance.

Dietary available phosphorus requirement of juvenile walking catfish,Clarias leather

A feeding trial was conducted to evaluate the optimum requirement of dietary available phosphorus (AP) for juvenile walking catfish, Clarias leather. Six practical diets were formulated to contain graded levels (2.2, 3.9, 5.5, 7.1, 8.8 and 10.4 g kg−1) of AP from dietary ingredients and monocalcium phosphate. Each diet was randomly fed to triplicate groups of fish with initial mean weight of 7.94 ± 0.08 g in floating cages (1.5 × 1.5 × 2.0 m) suspended in an earthen pond, and each cage was stocked initially with 60 fish. Fish were fed thrice daily (07:30, 13:00 and 17:30) to apparent satiation for 10 weeks. Both specific growth rate (SGR) and protein efficiency ratio significantly increased with increasing AP from 2.2 to 5.5 g kg−1 (P < 0.05) and then levelled off. Dietary AP levels significantly influenced whole-body protein, lipid and ash contents as well as condition factor and hepatosomatic index (P < 0.05). Whole-body and vertebrae phosphorus contents showed similar patterns as SGR in response to dietary AP content. Broken-line analyses based on SGR, phosphorus contents in the vertebrae and whole-body indicated the AP requirements were 5.8, 7.2 and 7.5 g kg−1, respectively.

Microbial phytase in finisher diets of White Pekin ducks: effects on growth performance, plasma phosphorus concentration, and leg bone characteristics

Two experiments (Exp.) were conducted to determine the growth response of White Pekin ducks to inclusion of microbial phytase in finisher diet. In Exp. 1, 1-d-old male ducks (240 total) were reared in litter-floor pens and fed regular starter diet until 3 wk of age. At 3 wk of age, ducks were randomly divided into six groups of 10 ducks each and each group was fed one of four diets. Three finisher diets containing 16% CP and 0.18% available phosphorus (AP) without supplemental P were formulated with microbial phytase (Natuphos) added at 0, 750, or 1,500 phytase units/kg of diet. The fourth diet was a control finisher diet that was supplemented with dicalcium phosphate (DCP) to supply dietary AP of 0.41%. Group BW and feed intake were measured weekly to assess growth response. At 6 wk of age, leg bones (tibia, femur, metatarsus) from five randomly selected ducks were removed and analyzed for bone characteristics. In Exp. 2, a total of 120 ducks reared as in Exp. 1 were randomly divided into six groups of five ducks each and fed one of four diets. A basal finisher diet was formulated to contain 16% CP and 0.18% AP. Monosodium phosphate was added to the basal diet to give dietary AP levels of 0.18, 0.27, and 0.36%. The fourth diet was the basal diet supplemented with microbial phytase (750 phytase units/kg of diet). Ducks were fed these diets from 3 to 6 wk of age. At the end of the study, ducks were bled by cardiac puncture and blood plasma was analyzed for P concentration. Leg bones from all ducks were removed and analyzed for bone characteristics as in Exp. 1. Feed intake increased linearly with increased level of dietary phytase, whereas the weight gain response was quadratic only during the last week of Exp. 1. In Exp. 2, there was a quadratic response for weight gain due to dietary AP. Weight gain due to phytase (750 units) was not different from ducks fed diets at 0 or 0.18% AP. Plasma P concentration increased linearly as dietary AP increased. Plasma P levels of ducks fed phytase were similar to those of ducks fed 0.18% AP but lower than in ducks fed 0.27% AP. Estimates of AP resulting from the addition of 750 units of phytase to basal diet were 0.05 and 0.07% based on plasma P concentration and weight gain, respectively. Using regression analysis, the AP due to phytase effect in the diet was estimated to range from 0.06 to 0.08%. Results suggest that phytase can be used in finisher diets similar to the one used in this study for ducks from 3 to 6 wk of age to improve growth performance and leg bone development similar to ducks fed diets supplemented with P from inorganic sources.

Available phosphorus requirements of food-size channel catfish ( Ictalurus punctatus) fed practical diets in ponds

A pond feeding experiment was conducted in which Year 2 channel catfish (average initial weight, 61 ± 5 g) were stocked in 400 m 2 earthen ponds (13950 fish ha −1) and fed an all-plant extrusion processed commercial type diet that contained 0.20, 0.27, 0.36, 0.44 and 0.60% available phosphorus from plant ingredients and monosodium phosphate. Availability of phosphorus in the basal diet and monosodium phosphate was determined by digestibility (net absorption) trials. All diets contained an inorganic calcium:available phosphorus ratio of 1:1. Each diet was fed to fish in four replicate ponds once daily to satiation throughout a 140 day growing season. Data for weight gain, feed conversion ratio, dressing percentage, serum phosphorus, serum alkaline phosphatase activity, bone ash, bone phosphorus, bone breaking strength, muscle composition and visceral fat were subjected to regression analysis to determine effects of the dietary levels of available phosphorus on these responses. There was no significant effect ( P > 0.10) of increasing dietary available phosphorus on weight gain, feed conversion, and dressing percentage. Serum phosphorus, bone ash, bone phosphorus, fat, moisture and protein contents of muscle and visceral fat showed significant linear responses ( P < 0.06) and serum alkaline phosphatase activity and bone breaking strength showed significant quadratic responses ( P < 0.04) with increasing concentrations of dietary available phosphorus. Broken-line analysis showed that maximum serum alkaline phosphatase activity and bone breaking strength were obtained at dietary available phosphorus concentrations of 0.25 and 0.31%, respectively. Data from this study indicated that an all-plant, commercial type diet with no phosphorus supplement, containing 0.20% available phosphorus, was sufficient for maximum weight gain by channel catfish grown to marketable size in ponds. Based upon alkaline phosphatase activity and bone strength, 0.3% available phosphorus is recommended for production diets for catfish grown in ponds. Increasing the dietary available phosphorus to higher concentrations appears to reduce muscle and visceral fat in intensively-fed, pond-grown channel catfish.

Effects of dietary calcium:available phosphorus ratio on calcium tolerance of broiler chickens

The effects of dietary levels of available phosphorus (AP) on calcium (Ca) tolerance of growing chickens were investigated in 3 experiments. In the first experiment, increasing dietary Ca to 21.2 g/kg with AP at 5 g/kg significantly reduced tibia P, plasma P and increased plasma total Ca concentration without any significant effect on performance. With dietary Ca at 25.7 g/kg and AP at 5 g/kg, growth and plasma P were reduced and plasma total Ca was increased, whilst Ca at 30 g/kg diet reduced growth, plasma P, tibia P and increased feed conversion ratio (FCR) and plasma total Ca. Increasing dietary AP to 10 g/kg diet with Ca level at 10.6 g/kg reduced growth and increased FCR without affecting any of the other parameters. Experiment 2 was a 3-dimensional composite design with a central basal diet having Ca and AP concentrations of 12.7 and 4.6 g/kg, The first dimension was 4 dietary concentrations of Ca from 15 to 30 g/kg; the second dimension was 4 dietary concentrations of AP from 6.3 to 12.4 g/kg; and the third dimension was 4 dietary Ca : AP combinations spanning the above ranges but with the Ca: AP ratio maintained at approximately 2.5 (i.e. 15.8 and 6.3; 20.5 and 8.2; 25.5 and 10.2; 30 and 12.1 g/kg for Ca and AP, respectively). A dietary Ca concentration of 25.4 g/kg increased FCR, whilst 30 g Ca/kg reduced growth and increased FCR. Dietary AP of 12.4 g/kg reduced growth and increased FCR. Growth and FCR were less affected when dietary Ca:AP ratio was kept constant at approximately 2.5 than when the ratio was altered by increasing either mineral alone. This relationship was used to develop a linear regression relationship between chicken growth and dietary Ca: AP ratio. In experiment 3, the effects of excessive dietary levels of Ca (12.7, 25.5 and 33.1 g/kg) and AP (9 and 13 g/kg) were investigated in sexed chickens in a factorial design. Ca at 33.1 g/kg significantly reduced growth, tibia P and plasma P, whilst FCR, plasma total Ca and excreta moisture were significantly increased. Dietary Ca at 25.5 g/kg reduced tibia P and increased excreta Ca. High dietary AP significantly reduced growth and tibia Ca and increased tibia ash, excreta moisture and excreta Ca. Significant interactions between dietary levels of Ca and AP were found for growth, tibia ash, excreta moisture and excreta Ca, and for tibia P and plasma total Ca. Significant interactions between sex and either dietary Ca or AP for tibia ash were found. A Ca x sex interaction was found for tibia P, excreta moisture and excreta P. It was concluded that high dietary levels of Ca (up to 21.2 g/kg) can be tolerated by growing chickens without any significant effect on performance, providing the corresponding level of AP is also high.

Influence of Phase Feeding Available Phosphorus on Egg Production Characteristics, Carcass Phosphorus Content, and Serum Inorganic Phosphorus Levels of Three Commercial Layer Strains

An experiment was conducted to obtain information on the concept of progressively decreasing dietary phosphorus levels (phase feeding) on the performance of three different commercial layer strains. Dietary available phosphorus (AP) levels of .15, .30, or .45% were fed continuously from 22 to 70 weeks of age. Concurrently, a diet containing .35, .25, and .15% AP was phase-fed during age intervals of 22 to 34, 34 to 50, and 50 t o 70 weeks, respectively. Dietary AP levels did not significantly affect egg production except the .15% AP level, which significantly reduced egg production when compared with the other three dietary AP treatments.Efficiency of feed utilization was significantly superior for hens phase-fed AP compared with hens fed the other AP treatments. There were no differences in egg weight or mortality due to dietary AP. Eggshells were significantly thicker when hens received .15% AP. The .15% AP and phase-fed regimen resulted in hens with significantly lower body weights at the end of the experiment. Hens fed .30% AP and phase-fed AP had significantly lower carcass ash and phosphorus levels. Serum phosphorus levels corresponded directly to dietary AP levels.There were no significant differences in egg production due to strain nor were there any strain by dietary treatment interactions that influenced production traits. Significant strain differences were noted in feed efficiency, egg weight, carcass ash, and carcass phosphorus.

Performance of Laying Hens Fed Various Phosphorus Levels Continuously or Phase Fed Decremental Phosphorus Levels

Two experiments were conducted to determine the influence of dietary phosphorus levels on performance of White Leghorn hens. In Experiment 1, dietary available phosphorus (AP) levels of .26, .36, .46, or .56% were fed continuously from 24 to 68 weeks of age. Concurrently, diets containing .46, .36, and .26% AP or .56, .46, and .36% AP were “phase fed” during the age intervals of 24 to 36, 36 to 48, and 48 to 68 weeks, respectively. Dietary AP levels of .16, .26, .36, and .46% were fed from 27 to 71 weeks in Experiment 2. Also, phosphorus was phase fed in this experiment at levels of .46, .36, and .26% AP or .36, .26, and .16% AP for ages 27 to 39, 39 to 51, and 51 to 71 weeks, respectively. No significant effects of dietary AP levels were observed in either experiment with respect to rate of egg production, feed efficiency, egg weight, eggshell thickness, changes in body weight, or mortality. In Experiment 1, rate of egg production, egg weight, and eggshell thickness of the hens fed .26% AP continuously were numerically less, and mortality was numerically greater, than those of hens fed higher AP levels. The percentage of ash and the quantities of phosphorus contained in carcasses (feather-free) at the end of Experiment 1 tended to be directly related to dietary AP level. Total carcass phosphorus of hens fed .26% AP continuously was reduced significantly as compared with all other treatment groups except for the hens fed .36% AP continuously. Neither concentration of carcass ash nor quantity of phosphorus in carcasses was affected consistently by dietary AP in Experiment 2.Assuming an average daily feed consumption of 95 to 100 g/hen, the results indicated that phase-feeding of dietary AP levels of .46, .36, and .26% and possibly .36, .26, and .16% during the age intervals of approximately 24 to 39, 39 to 51, and 51 to 71 weeks, respectively, will support high rates of egg production without excessive depletion of body phosphorus.