Studies on the Availability of Calcium Orthophosphates to Chickens and Turkeys

Evaluation of Phosphorus Digestibility from Monocalcium and Dicalcium Phosphate Sources and Comparison between Total Tract and Prececal Digestibility Standard Methods in Broilers

Simple Summary

Variations in phosphorous (P) digestibility as a function of methodology, phosphate source, physicochemical characteristics and commercial source were evaluated in broilers. Three methodologies and two phosphates (monocalcium phosphate, MCP, and dicalcium phosphate, DCP) from three different commercial sources were used in two experiments. In the first experiment, MCP and DCP were incorporated into a P-deficient diet at two levels of inclusion and P digestibility was evaluated using three methodologies of the regression method (total excreta, marker in excreta and prececal digestibility). In the second experiment, variations in P digestibility of six phosphate sources (three MCP and three DCP) were evaluated using the total collection method. The P digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies (p > 0.05). Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the three tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05.

Abstract

The objective of this study was to compare the total tract (total excreta and marker) and prececal methodologies to determine phosphorus (P) digestibility and to evaluate its variation as a function of the physicochemical characteristics of the inorganic phosphate used (monocalcium, MCP and dicalcium, DCP) from different commercial sources. A total of 176 1-day-old male broilers were used in two digestibility experiments. In Experiment 1, one MCP and one DCP were incorporated in the basal diet at two levels. In Experiment 2, MCP and DCP from three commercial sources were incorporated to the basal diet at one level. Physicochemical characteristics of inorganic phosphates were examined, as well. Additionally, bone mineralization and growth performance traits were investigated in both trials. The digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies, but differences between total tract and preceal methodologies were not statistically significant. Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the 3 tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05.

Estimation of Phosphorus and Nitrogen Waste in Rainbow Trout (Oncorhynchus mykiss, Walbaum, 1792) Diets Including Different Inorganic Phosphorus Sources

Simple Summary

Aquaculture effluents with high levels of phosphorus (P) and nitrogen (N) contribute to eutrophication in the aquatic ecosystem. The environmental impact of phosphorus and N aquaculture waste may be diminished by modifying diet ingredients that improve phosphorous (P) digestibility, and therefore, reduce the P in metabolic waste. The content of P in fishmeal is high (30 g/kg), but the inclusion of fishmeal in the diet is reducing due to its high costs and limited accessibility; therefore, the addition of an inorganic P source is necessary to ensure a satisfactory level of available P in fish diets. Consequently, the present study aimed to evaluate the effect of four different inorganic P sources on P digestibility and excretion in rainbow trout (Oncorhynchus mykiss), as one of the most relevant aquaculture species. Monosodium/monocalcium phosphate with 2% of sodium source presented a P digestibility similar to monoammonium phosphate, but with lower nitrogen and phosphorus excretion into the environment, which is advantageous from a nutritional, environmental and industrial point of view (biofilters and recirculation systems in fish farms).

Abstract

This study was conducted to evaluate the apparent availability and P and N excretion in rainbow trout (Oncorhynchus mykiss) using different inorganic phosphorus sources. With this goal, fish (153 ± 14.1 g) fed four inorganic P sources were assayed: monoammonium phosphate (MAP, NH₄H₂PO₄), monosodium/monocalcium phosphate (SCP-2%, AQphos+, NaH₂PO₄/Ca(H₂PO₄)₂·H₂O in proportion 12/88), monosodium/monocalcium phosphate (SCP-5%, NaH₂PO₄/Ca(H₂PO₄)₂·H₂O in proportion 30/70) and monocalcium phosphate (MCP, Ca(H₂PO₄)₂·H₂O). Phosphorus (P) digestibility, in diets that included MAP and SCP-2% as inorganic phosphorus sources, were significantly higher than for SCP-5% and MCP sources. In relation to the P excretion pattern, independent of the diet, a peak at 6 h after feeding was registered, but at different levels depending on inorganic P sources. Fish fed an MAP diet excreted a higher amount of dissolved P in comparison with the rest of the inorganic P sources, although the total P losses were lower in MAP and SCP-2% (33.02% and 28.13, respectively) than in SCP-5% and MCP sources (43.35% and 47.83, respectively). Nitrogen (N) excretion was also studied, and the fish fed an SCP-5% diet provided lower values (15.8%) than MAP (28.0%). When N total wastes were calculated, SCP-2% and SCP-5% showed the lowest values (31.54 and 28.25%, respectively). In conclusion, based on P and N digestibility and excretion, the SCP-2% diet showed the best results from a nutritional and environmental point of view.

Management of phosphorus nutrition of beef cattle grazing seasonally dry rangelands: a review

This review examines the effects of phosphorus (P) deficiency as a major constraint to productivity of cattle grazing rangelands with low-P soils. Nutritional deficiency of P may severely reduce liveweight (LW) gain of growing cattle (e.g. by 20–60 kg/annum) and the productivity of breeder cow herds as weaning rate, mortality and calf growth. In seasonally dry tropical environments, the production responses to supplementary P occur primarily during the rainy season when the nutritional quality of pasture as metabolisable energy (ME) and protein is high and pasture P concentration is limiting, even though the P concentrations are higher than during dry season. When ME and nitrogen of rainy-season pasture are adequate, then P-deficient cattle typically continue to gain LW slowly, but with reduced bone mineralisation (i.e. osteomalacia). In beef breeder herds when diet P is insufficient, cows with high bone P reserves can mobilise bone P reserves during late pregnancy and early lactation. Mobilisation may contribute up to the equivalent of ~7 g diet P/day (one-third of the P requirements) in early lactation, and, thus, allow acutely P-deficient breeders to maintain calf growth for at least several months until depletion of cow body P reserves. However, severe P deficiency in cattle is usually associated with reduced voluntary intake (e.g. by 20–30% per kg LW), severe LW loss and poor reconception rates. When P intake is greater than immediate requirements, breeders can replenish bone P. Replenishment in mature cows occurs slowly when ME intake is sufficient only for slow LW gain, but rapidly at ME intakes sufficient for rapid LW gain. Bone P replenishment also occurs in late-pregnant heifers even when losing maternal LW. Intervals of mobilisation and replenishment of body P reserves will often be important for P nutrition of beef breeder cows through annual cycles. Diagnosis of P deficiency in grazing cattle is difficult and must encompass estimation of both diet P intake and availability of P from body reserves. Cattle behaviour (e.g. pica, osteophagea), low soil P concentrations and low herd productivity provide valuable indicators. Some constituents of blood (plasma inorganic P, calcium, plasma inorganic P:calcium ratios and endocrine markers) are valuable indicators, but the threshold values indicative of P deficiency at various ME intakes are not well established. It is evident that knowledge of both the nutritional physiology and requirements for P provide opportunities to better manage P nutrition to alleviate production losses in low-input systems with beef cattle grazing rangelands.

Comparação de métodos "in vitro" para determinação da biodisponibilidade de fósforo

Avaliou-se a solubilidade do fósforo presente em seis fontes por meio da utilização de sete extratores. As fontes de fósforo foram: fosfato bicálcico (FB), fosfato monoamônico (MAP), fosfato supertriplo (FST), fosfato de rocha de Araxá (FRA), farinha de ossos calcinada (FOC) e farinha de ossos autoclavada (FOA). Os extratores foram: água, ácido cítrico nas concentrações de 2% (AC2), 10% (AC10), 20% (AC20) e 30% (AC30), ácido clorídrico na concentração de 0,5% (HCl) e o citrato neutro de amônio (CNA). O procedimento de laboratório foi padronizado independente do extrator utilizado. O fósforo presente no FB foi pouco solubilizado pela água (33,8%), além disso, o fósforo da FOC, da FOA e do FRA foi praticamente insolúvel nesse extrator. O HCl solubilizou o fósforo contido na FOC e no FRA da mesma forma e em níveis abaixo de 50% (42,7% e 42,9% respectivamente). O CNA solubilizou apenas 47,1% do fósforo presente na FOA e o fósforo da FOC e do FRA foi praticamente insolúvel nesse extrator. O AC2 solubilizou o fósforo presente na FOC e no FRA em níveis abaixo de 50% (38,7% e 20,8% respectivamente). Tanto o AC20 quanto o AC30 solubilizaram o fósforo presente no FRA acima de 50% (53,2% e 59,5%, respectivamente). O AC10 apresentou os resultados mais promissores como extrator para determinação indireta do valor biológico de fontes de fósforo de variadas origens, pois solubilizou o fósforo do FRA em um nível inferior a 50% (44,6%) e o fósforo das demais fontes em níveis que variaram de 82,2% a 100%.

Laboratory evaluations of feed-grade and agricultural-grade phosphates

Nine samples of pure, feed-grade (FP) and agricultural-grade (AP) phosphates were evaluated at seven laboratories (six in Brazil and one in the U.S.) for physical and chemical characteristics. Phosphates were one "standard" pure dicalcium phosphate; four FP, two dicalcium phosphates (FP-1 and FP-2) made in Brazil, one di-monocalcium phosphate (FP-3), and one defluorinated phosphate (FP-4) made in the U.S.; and four AP made in Brazil [single superphosphate (AP-1), triple superphosphate (AP-2) and monoammonium (AP-3), and thermomagnesium (AP-4) phosphates]. Average analytical values for FP and AP, respectively, were 3.3 and 6.3% moisture, 1.0 and 2.5% insoluble residue, 16.2 and 28.4% loss on ignition, 6.8 and 4.7 (pH), 1,028 and 1,023 g/L apparent density, 9.6 and 55.0% P solubility in water, 83.6 and 88.4% P solubility in 2% citric acid, and 85.2 and 97.0% P solubility in neutral ammonium citrate. Based on particle size, six products were classified as "fine," and three were classified as "irregular." Atomic absorption and plasma spectrometry determinations were performed for 31 essential and potentially harmful or radioactive minerals. The Na level was high in FP-4 (6.03%). Mineral concentrations were safe for all FP as compared with NRC standards. Levels in AP were toxic, exceeding the tolerance limits for F, Fe, Mg, and Ba, and were particularly high as compared with FP for S, Ti, and radioactive Th. The AP-1 was high in F, Ba, S, and Th; AP-2 and AP-3 were high in F and S; and AP-4 was high in F, Ba, Fe, Mg, Ti, and Th. X-ray diffraction assays detected impurities for all commercial samples and identified as major components CaHPO4*2H2O (standard phosphate), CaCO3 and CaHPO4 (FP-1, FP-2, and FP-3), Ca(H2PO4)2*H2O (FP-3), Na2Ca3Al2(PO4)2(SiO4)2 and Ca3(PO4)2 (FP-4), CaSO4*nH2O and (NH4)Fe3P6O20*(PO4)2 (AP-1), Ca(H2PO4)2*H2O and KFe3P6O20*10H2O (AP-2), (NH4)H2PO4 and CaSO4*nH2O (AP-3), and no definite molecular structure for AP-4, an amorphous product. The biological consequences of feeding animals a mineral source with no definite molecular structure, an amorphous product, is not known. A biological evaluation of all phosphates included in this article is being published as a separate report (Fernandes et al., 1999).

Biological evaluations of commercial dicalcium phosphates as sources of available phosphorus for broiler chicks

One thousand male Hubbard chicks were used in a 21-d study (10 birds per battery cage) to determine relative biological availability of phosphorus in seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate. Five samples were from established producers in Brazil and two from the U.S. Pure calcium phosphate dibasic dihydrate was used as the reference standard. Phosphates were added to the corn-soybean basal diet (22.5% CP; 0.4% total phosphorus) to provide 0.1, 0.2, and 0.3% supplemental phosphorus. The calcium level was 1.0% for all diets. Left tibias were removed for bone ash (BA) and bone strength (BS) determination. Body weight, feed intake (FI), BA, BS, and plasma phosphorus increased (P < 0.01) and plasma calcium and alkaline phosphatase decreased (P < 0.01) with increasing dietary phosphorus regardless of source. The availability of phosphorus for each test phosphate was determined by slope ratio, with BW, BA, and BS regressed on phosphorus added within each phosphorus source. A relative biological value (RBV) was calculated based on BW, BA, and gain:feed ratio. Availability based on BW ranged from 97.07 to 110.41%. When BA was the criterion, values were 80.32 to 107.84% and for BS were 79.34 to 110.52%. The RBV ranged from 97.55 to 100.60%. Phosphate sources did not vary greatly in phosphorus availability. Overall phosphorus availability averages were higher for BW (103%) and RBV (99%) and lowest for BA (96%) and BS (94%).

Chemical and physical evaluations of commercial dicalcium phosphates as sources of phosphorus in animal nutrition

Seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate, from five established producers in Brazil and two in the United States, were evaluated and compared with a purified grade calcium phosphate dibasic dihydrate used as a reference standard. All samples were submitted to a wide range of tests at seven laboratories. Each determination was performed at least at two different laboratories, except for moisture, insoluble residue, loss on ignition, and x-ray diffraction assays, obtained from one single laboratory. All phosphate samples studied were in compliance with the manufacturer's levels of guarantee, except for three samples that were slightly out of specification (Ca, P, and F). Particle size patterns were variable, allowing for a classification of two products as "coarse", three as "fine", and three as "irregular". Phosphorus solubility in 2% citric acid ranged from 85.9 to 97.6%, pH from 3.2 to 6.1, and apparent density from 572 to 967 g/L. Atomic absorption or plasma emission spectrometry concentrations (average parts per million) for Al (3,200), As (10), B (14), Ba (165), Bi (< .1), Cd (6), Cr (57), Co (11), Cu (28), Fe (7,515), Hg (< .2), Mg (11,300), Mn (367), Mo (6), Ni (25), Pb (17), Se (< .5), Sb (1.3), Th (19), U (51), V (134), W (< 5), and Zn (152) were safe for all phosphates as compared to NRC standards. X-ray diffraction detected CaCO3 and impurities for all commercial samples, dolomite for three phosphates. Monocalcium phosphate was found in four samples. Aluminum salts present were identified as the low solubility, low toxicity silicates, and phosphates.

Laying hens respond differently to high dietary levels of phosphorus in monobasic and dibasic calcium phosphate

A series of experiments were conducted to determine the relative acidogenicities of dietary chloride, phosphorus, and sulfate and their effects on shell quality. Calcium salts of these anions were added to a corn-soybean meal diet to provide supplemental levels of 150 to 450 meq/kg diet chloride, 150 to 600 meq/kg diet monobasic phosphate, 150 to 1,200 meq/kg diet dibasic phosphate, and 150 to 1,200 meq/kg diet sulfate. The results indicated that laying hens can safely tolerate up to 200 meq/kg diet supplemental chloride (.95% total chloride in the diet) and up to 450 to 600 meq/kg diet supplemental sulfate (2.16 to 2.88% added sulfate). Levels higher than these adversely affected shell quality and altered blood acid-base balance. Laying hens responded quite differently to phosphorus when it was supplied as monobasic or dibasic phosphate. Supplemental levels of 900 to 1,200 meq/kg diet dibasic phosphate (1.95 to 2.41% total phosphorus) did not have an adverse effect on performance and up to a supplemental level of 450 meq/kg diet (1.25% total phosphorus) did not affect shell quality. In contrast, performance was seriously impaired by a supplemental level of 150 meq/kg diet monobasic phosphate (1.02% total phosphorus in the diet). The results further indicated that phosphate in monobasic (but not in dibasic) form is a strong acidogenic anion and that most of its adverse effect on performance and shell quality can be ameliorated by alkaline salts of sodium or potassium bicarbonate. The relative acidogenicities of calcium salts of these acidic anions were as follows: phosphate (monobasic) > chloride > sulfate > phosphate (dibasic).

Bioavailability of phosphorus from various phosphates based on body weight and toe ash measurements

Two experiments involving 1,152 turkeys were conducted to determine the relative bioavailability of phosphorus of eight phosphates from commercial and experimental sources. The basal diet, composed of 52% dehulled soybean meal and 41% ground yellow corn, contained 1.48% calcium and .44% total phosphorus. Phosphorus from the eight sources was added to the basal diet at levels of .09, .18, or .27% to form 24 diets with a constant calcium content. Each diet was fed to one pen of eight males and eight females from 1 to 4 wk of age in the first experiment and to two pens (one of each sex) of 16 poults/pen from 0 to 4 wk of age in the second experiment. Measurements of percentage ash of the middle toe pooled from all poults within a pen and of average body weight at 4 wk of age provided similar relative phosphorus availability values. With the phosphorus in monocalcium phosphate as the standard set at 100%, phosphorus from two sources of dicalcium phosphate and one source of defluorinated phosphate were found not significantly different in bioavailability (95, 105, and 103%, respectively). Phosphorus in curacao phosphate was only 55% available and in the three experimental defluorinated phosphates, phosphorus was 81, 70, and 87% available. Significant differences in bioavailability between two samples greater than 13 and 18% were found when using toe ash and body weight measurement, respectively.

Availability of phosphorus from ammonium polyphosphate for growing chickens

Phosphorus from ammonium polyphosphate was equivalent in availability to that of other phosphate sources commonly used in broiler rations, and it was more available than that from reagent-grade tricalcium phosphate. Two three-week experiments conducted with broiler chickens showed that growth rate, feed efficiency, viability, and bone calcification were improved to a similar extent by adding an equivalent increment of phosphorus from dicalcium phosphate, defluorinated phosphate, or ammonium polyphosphate. The results of these experiments suggest that ammonium polyphosphate may be a useful phosphorus supplement for practical poultry rations.