Precaecal phosphorus digestibility of inorganic phosphate sources in male broilers

A review of calcium and phosphorus requirement estimates for gestating and lactating sows

Calcium (Ca) and phosphorus (P) are minerals involved in biological functions and essential structural components of the skeleton. The body tightly regulates Ca and P to maintain homeostasis. Maternal needs for Ca and P increase during gestation and lactation to support conceptus growth and milk synthesis. Litter size and litter average daily gain (ADG) have a large effect on Ca and P requirements for sows because as they increase, the requirements increase due to a greater need from the sow. The objective of this review was to summarize published literature on Ca and P requirements in gestating and lactating sows derived from empirical data and factorial models. A total of nine empirical studies and seven factorial models were reviewed for determining the Ca and P requirements in gestation. For lactation, there were six empirical studies and seven factorial models reviewed. Empirical studies determined requirements based on the observed effect of Ca and P on bone mineralization, sow and litter performance, and milk characteristics. Factorial models generated equations to estimate Ca and P requirements using the main components of maintenance, fetal and placental growth, and maternal retention in gestation. The main components for factorial equations in lactation include maintenance and milk production. In gestation, the standardized total tract digestible phosphorus (STTD P) requirement estimates from empirical studies range from 5.4 to 9.5 g/d with total Ca ranging from 12.9 to 18.6 g/d to maximize bone measurements or performance criteria. According to the factorial models, the requirements increase throughout gestation to meet the needs of the growing fetuses and range from 7.6 to 10.6 g/d and 18.4 to 38.2 g/d of STTD P and total Ca, respectively, on day 114 of gestation for parity 1 sows. During lactation, STTD P requirement estimates from empirical studies ranged from 8.5 to 22.1 g/d and total Ca ranged from 21.2 to 50.4 g/d. For the lactation factorial models, STTD P requirements ranged from 14.2 to 25.1 g/d for STTD P and 28.4 to 55.6 g/d for total Ca for parity 1 sows with a litter size of 15 pigs. The large variation in requirement estimates makes it difficult to define Ca and P requirements; however, a minimum level of 6.0 and 22.1 g/d of STTD P during gestation and lactation, respectively, appears to be adequate to meet basal requirements. The limited data and high variation indicate a need for future research evaluating Ca and P requirements for gestating and lactating sows.

Effect of replacing dicalcium phosphate with mono-dicalcium phosphate to supplement phosphorus on laying performance, phosphorus-calcium metabolism and bone metabolism of aged laying hens

The objective of this study was to evaluate the effect of replacing dicalcium phosphate (DCP) with mono-dicalcium phosphate (MDCP) to formulate low-phosphorus (P) diets on laying performance, egg quality, phosphorus-calcium metabolism, and bone metabolism of 69-78-week-old aged laying hens. Hy-Line Brown laying hens (n = 1,350, 69 weeks old) were randomly assigned to six treatments, each with five replicates of 45 hens. A corn-soybean meal-based diet was formulated to contain 0.12% non-phytate phosphorus (NPP), 3.81% calcium (Ca), and 1,470 FTU/kg phytase. The control group (CON) was supplemented with DCP inorganic phosphorus (Pi) at the NPP level of 0.20% (dietary NPP levels of 0.32%). Test groups (T1-T5) were supplemented with MDCP Pi at NPP levels of 0.07%, 0.11%, 0.15%, 0.18, and 0.20% (dietary NPP levels of 0.19, 0.23, 0.27, 0.30, and 0.32%, respectively). Calcium carbonate levels were adjusted to ensure all experimental diets contained the same Ca levels (3.81%). The feeding trial lasted 10 weeks, with hens increasing in age from 69 to 78 weeks. When supplemented with 1,470 FTU/kg phytase, extra DCP Pi or MDCP Pi did not affect (p > 0.05) laying performance (day laying rate, average egg weight, feed intake, feed-to-egg mass ratio, broken egg rate), egg quality (eggshell strength, albumen height, haugh units), or serum P, Ca, copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) levels. However, when laying hens were fed MDCP Pi (NPP levels of 0.07 to 0.20%), yolk color improved (p = 0.0148). The tibia breaking strength was significantly higher (p < 0.05) in the 0.18 and 0.20% NPP MDCP Pi groups than in the 0.20% NPP DCP Pi group. The breaking strength, Ca content, and P content of tibia in 0.11% and 0.15% NPP MDCP Pi hens were not significantly (p > 0.05) different from those in 0.20% NPP DCP Pi hens. Hens fed 0.07% NPP MDCP Pi had higher (p < 0.01) serum levels of osteoprotegerin (OPG), type-I collagen c-telopeptide (CTX-I), and tartrate-resistant acid phosphatase 5b (TRACP-5b) than those in all other groups. Serum levels of TRACP-5b and CTX-I in the 0.11% and 0.15% NPP MDCP Pi group were significantly lower than those in 0.18 and 0.20% NPP MDCP Pi groups and the 0.20% NPP DCP Pi group (p < 0.0001). Hens fed 0.07% and 0.11% NPP MDCP Pi had higher (p < 0.05) serum levels of parathyroid hormone (PTH) than those in all other groups. No differences were detected in serum calcitonin (CT), 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3), bone alkaline phosphatase (BAP), osteocalcin(OCN), and osteopontin (OPN) among all groups (p > 0.05). The expression of P transporters type IIa Na/Pi cotransporter (NaPi-IIa) in 0.11% and 0.15% NPP MDCP Pi hens were higher than those in 0.20% NPP MDCP Pi group and 0.20% NPP DCP Pi group (p < 0.05). The results indicated that both renal P reabsorption and bone resorption were involved in adapting to a low-P diet. In summary, when MDCP was used instead of DCP to supplement P, NPP levels could be reduced to 0.11% (dietary NPP level of 0.23%) without negative effects on laying performance and skeletal health of aged hens. In addition, MDCP was more beneficial than DCP for tibia quality. The results of the current study would provide references for the application of MDCP in low-P diets of aged laying hens.

From sewage sludge ash to a recycled feed phosphate - digestibility of precipitated calcium phosphate in broiler chickens and growing pigs

Today, EU is largely (∼92%) dependent on the import of phosphates as most mines are located outside Europe. Because of the limited availability, phosphorus (P) is included on the list of Critical Raw Materials. Precipitated calcium phosphate (PCP) recovered from sewage sludge ash is a novel and sustainable option to replace mined P as raw material in feed phosphates, e.g. monocalcium phosphate (MCP) or dicalcium phosphate, but the digestibility has not yet been tested in vivo. The aim was therefore to determine PCP and MCP apparent ileal digestibility (AID) of P in broiler chickens and apparent (ATTD) and true (TTTD) total tract digestibility of P in growing pigs. A chicken study comprised 240 Ross 308 chickens that were housed in groups of eight from day 21 to day 28. Five diets were used, a basal diet and two test diets, which contributed either 0.075% (low) or 0.150% (high) additional P for each of the test sources (MCP and PCP). The basal and test diets were composed to achieve increasing levels of P and AID was calculated with regression analysis. In the pig study, eight individually housed pigs were used in a change-over study with two experimental periods. The pigs were fed a basal P-free diet in a preperiod to be able to estimate endogenous P losses and then two different diets in two periods using a change-over design, where MCP and PCP were the only P source, providing in total 0.33 (basal diet), 4.42 (MCP) and 3.53 (PCP) g kg^-1P, respectively. The AID of P in PCP and MCP for chickens was 58.4 and 75.1% (P = 0.166). The ATTD and TTTD of P in PCP for pigs were 58.4 and 67.2%, respectively, which was lower (P < 0.001) than the corresponding values for MCP (82.1 and 89.1%), respectively. The digestibility of calcium (Ca) did not differ in the chicken diets with high inclusion levels of PCP and MCP (54.7 and 55.3%, respectively, P = 0.535), but was lower for PCP than MCP in the pig study (57.8 and 70.8% respectively, P = 0.001). In conclusion, the digestibility of P in PCP for chickens did not differ from conventional MCP, whereas for pigs, it was lower, but could be a viable alternative to other common sources of P.

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.

Ileal Digestibility and Total Tract Retention of Phosphorus in Inorganic Phosphates Fed to Broiler Chickens Using the Direct Method

The objective of this study was to determine and compare the phosphorus (P) utilization of inorganic phosphates fed to broiler chickens using the direct method. On day 15 of age, six hundred forty 15-day-old male Ross 308 broiler chickens (initial body weight = 399 ± 38 g) were assigned to five experimental diets with 16 birds per cage in a randomized complete block design. The experimental diets consisted of four semi-purified diets containing monocalcium phosphate, monodicalcium phosphate, dicalcium phosphate, and tricalcium phosphate as the sole P sources. Additionally, a P-free diet was prepared to measure basal endogenous P loss. Chromic oxide was added to the experimental diets as an indigestible index. Excreta were collected per cage on days 17 to 18 of age, and all birds were asphyxiated with carbon dioxide on day 19 of age for ileal digesta collection. The cage was an experimental unit, and the number of replications per each treatment was eight except for the tricalcium phosphate treatment (n = 4). There was no interaction observed between the P source and the collection site (ileal digestibility vs. total tract retention). Phosphorus utilization differed (p < 0.05) among inorganic phosphates and the ileal digestibility of P was greater (p < 0.05) than the total tract retention. In conclusion, the standardized ileal digestibility of P in inorganic phosphates ranged from 56.7% to 89.8% and ileal digestibility was greater than the total tract retention.

Effect of inorganic phosphate supplementation on egg production in Hy-Line Brown layers fed 2000 FTU/kg phytase

Phytase has long been used to decrease the inorganic phosphorus (Pi) input in poultry diet. The current study was conducted to investigate the effects of Pi supplementation on laying performance, egg quality and phosphate-calcium metabolism in Hy-Line Brown laying hens fed phytase. Layers (n = 504, 29 weeks old) were randomly assigned to seven treatments with six replicates of 12 birds. The corn-soybean meal-based diet contained 0.12% non-phytate phosphorus (nPP), 3.8% calcium, 2415 IU/kg vitamin D3 and 2000 FTU/kg phytase. Inorganic phosphorus (in the form of mono-dicalcium phosphate) was added into the basal diet to construct seven experimental diets; the final dietary nPP levels were 0.12%, 0.17%, 0.22%, 0.27%, 0.32%, 0.37% and 0.42%. The feeding trial lasted 12 weeks (hens from 29 to 40 weeks of age). Laying performance (housed laying rate, egg weight, egg mass, daily feed intake and feed conversion ratio) was weekly calculated. Egg quality (egg shape index, shell strength, shell thickness, albumen height, yolk colour and Haugh units), serum parameters (calcium, phosphorus, parathyroid hormone, calcitonin and 1,25-dihydroxyvitamin D), tibia quality (breaking strength, and calcium, phosphorus and ash contents), intestinal gene expression (type IIb sodium-dependent phosphate cotransporter, NaPi-IIb) and phosphorus excretion were determined at the end of the trial. No differences were observed on laying performance, egg quality, serum parameters and tibia quality. Hens fed 0.17% nPP had increased (P < 0.01) duodenum NaPi-IIb expression compared to all other treatments. Phosphorus excretion linearly increased with an increase in dietary nPP (phosphorus excretion = 1.7916 × nPP + 0.2157; R2 = 0.9609, P = 0.001). In conclusion, corn-soybean meal-based diets containing 0.12% nPP, 3.8% calcium, 2415 IU/kg vitamin D3 and 2000 FTU/kg phytase would meet the requirements for egg production in Hy-Line Brown laying hens (29 to 40 weeks of age).

Determination of true ileal phosphorus digestibility of maize and soybean meal and true ileal calcium digestibility of soybean meal for broiler chickens

Two experiments were conducted, using the regression method, to determine the true ileal phosphorus (P) digestibility of maize and soybean meal (SBM), and true ileal calcium (Ca) digestibility of SBM for broiler chickens. The aim of Experiment 1 was to determine true ileal P digestibility of maize and SBM. The experimental diets were formulated with four inclusion levels of each test ingredient to achieve graded concentrations of total P (2.5, 3.0, 3.5 and 4.0 g/kg, respectively). The P concentrations in maize-based diets were adjusted by the inclusion of monosodium phosphate. The Ca:total P ratio in all diets was maintained at 1.35 by the addition of limestone. Experiment 2 was conducted to determine true ileal Ca digestibility of SBM. Experimental diets were formulated to contain four levels of SBM to achieve graded concentrations of Ca (2.5, 3.0, 3.5 and 4.0 g/kg, respectively). Because of the low concentration of Ca in SBM, all diets were supplemented with a similar level of limestone to prevent any Ca deficiency. The Ca:total P ratio in all diets was adjusted to be equal by the addition of monosodium phosphate. In both experiments, titanium dioxide (3 g/kg) was used as the indigestible marker. One-day-old male broiler chicks were fed a commercial starter diet from 1 to 21 days of age. On Day 22, a total of 240 and 120 birds were assigned to eight and four dietary treatments in Experiments 1 and 2, respectively, with five replicate cages and six birds per cage. Birds were fed the experimental diets for 7 days. On Day 29, ileal digesta were collected from the posterior half of ileum, and the true P and Ca digestibility of test ingredients were calculated by linear regression analysis. True P digestibility of maize and SBM were determined to be 33.8% and 42.3%, respectively. True Ca digestibility of SBM was determined to be 45.9%.