Digestibility of calcium and digestible calcium from inorganic sources evaluated in swine by two methods

SUMMARY The objective of the study was to determine the digestible calcium from different sources by direct and indirect methods. Thirty castrated male pigs were used, distributed in randomized blocks, in six treatments: 1- Calcitic limestone; 2-Dicalcium phosphate powder 18%; 3- Dicalcium phosphate powder 20%; 4- Dicalcium microgranulated phosphate 18%; 5- Monodicalcium microgranulated phosphate 20%; 6- Monodicalcium microgranulated phosphate 21%, with six replicates and one animal per experimental unit. A basal diet was formulated to meet the nutritional requirements of the animals, except for calcium (0.06%) and the evaluated sources replaced the basal diet in order to provide 0.45% of total Ca. At the same time, two stool collection methods were evaluated: total collection and fecal indicator. The animals were housed in metabolism cages for 12 days to collect feces and urine to determine the calcium values used to estimate digestibility coefficients and digestible calcium. The total collection method and the faecal indicator method did not affect the true digestibility coefficient of calcium. The calcium digestibility of the microgranulated dicalcium phosphate 21% (MM21) was superior in comparison with the other calcium sources evaluated by the indirect method in the present study. The average values of true digestibility of the calcium sources, in percentage, were: calcitic limestone: 82.47; dicalcium phosphate powder 18%: 80.87; dicalcium phosphate powder 20%: 85.65; dicalcium microgranulated phosphate 18%: 81.65; monodicalcium microgranulated phosphate 20%: 84.15; and monodicalcium microgranulated phosphate 21%: 88.35. The two methodologies can be used to determine the digestibility of calcium.

The effect of particle size of commercial soybean meal on performance and nutrient utilization of broiler chicks

An experiment was conducted to determine the effects of soybean meal (SBM) particle size on broiler performance, particularly P utilization. This experiment utilized a 2 x 2 x 2 factorial design with the following variables: SBM particle size, P level, and diet type, either corn-SBM or semipurified. SBM was obtained from a processing plant before (geometric mean diameter 1,239 microm) and after (891 microm) hammer milling. The P levels were 0.5% total P for deficient diets and 0.7% total P for adequate P diets. The coarse SBM improved bone ash (P < 0.05), gain:feed ratios (P < 0.1), and plasma P levels (P < 0.1). The diets with 0.5% P resulted in overall poorer performance as 16-d BW was reduced, gain:feed ratio decreased, bone ash decreased, and rickets incidence increased. Chicks fed the semipurified diets also had lower 16-d BW, lower gain-to-feed ratio, and lower bone ash. There was a significant interaction between the diet type and the soy particle size when the corn-SBM meal diets were fed because the coarse SBM increased plasma P levels, whereas there was little effect when the semipurified diets were fed. There were also significant interactions observed between these variables on growth and gain:feed ratio in that the coarse SBM elicited a much more dramatic response when incorporated into the semipurified diets as opposed to the corn-SBM diets. The results suggest that large particle size soybean meal may be more efficiently utilized than fine particle size soybean meal.

Uso de Fosfato Bicálcico Granulado Sobre o Desempenho e Mineralização Óssea de Frangos de Corte

O objetivo do experimento foi avaliar os efeitos do tamanho da partícula do fosfato bicálcico (fina ou granulada) e dos níveis de fósforo total sobre o desempenho de frangos de corte e sobre os teores de cálcio, fósforo e magnésio dos ossos. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 3x2 com 3 níveis de fósforo total (0,5%; 0,6% e 0,7%) e duas granulometrias de fosfato bicálcico (fina e granulada). Foram utilizados 300 pintos de corte com um dia de idade, machos, da linhagem Cobb, alojados em baterias metálicas em 6 tratamentos com 5 repetições de 10 aves, totalizando 30 gaiolas dispostas em 6 baterias de 5 andares cada. Os resultados demonstraram que o uso do fosfato granulado resultou em melhor desempenho dos animais. Aves alimentadas com o nível de 0,5% de fósforo total apresentaram o pior desempenho, sendo que o nível de 0,6% proporcionou melhor desempenho das aves. As diferentes granulometrias do fosfato, não diferiram estatisticamente quanto a percentagem de matéria mineral, cálcio, fósforo e magnésio nos ossos.

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.

Effects of particle size on the biological availability of calcium and phosphorus in defluorinated phosphate for chicks

A total of 576 d-old, male, broiler chicks were used in two trials 1) to determine the range of Ca and P levels over which the response in bone characteristics is linear and 2) to determine the influence of particle size of defluorinated rock phosphate (DFP) on the bioavailability of Ca and P in DFP. Six treatments were used in Experiment 1 in which varying percentages of added Ca (.00, .06, .12, .24, .36, and .48%) and added P (.00, .05, .10, .20, .30, and .40%) were evaluated in a corn-soybean meal diet containing 23% CP, .47% Ca, and .39% P (.14% available P). Weight gain, feed intake, and tibia breaking strength increased (P less than .001) with increasing levels of dietary Ca and P. Treatments in Experiment 2 consisted of: 1) Diet 1, a corn-soybean meal basal diet (23% CP, .50% Ca, .46% P, .21% available P), 2) Diet 1 with .12% added Ca from calcium carbonate (CC) and .07% added P from monosodium phosphate (MSP), 3) Diet 1 with .24% added Ca from CC and .14% added P from MSP; and 4 to 8), Diet 1 with .24% added Ca and .14% added P from five particle sizes of DFP. Feed intake, weight gain, and tibia breaking strength and ash percentage increased linearly (P less than .01) and feed:gain ratio decreased quadratically (P less than .10) with increasing percentages of added Ca and P in Diets 1 to 3.(ABSTRACT TRUNCATED AT 250 WORDS)