Precipitated Bone Phosphate in Broiler Chick Diets 1 B. L. DAMRON and L. K. FLUNKER Department of Poultry Science, University of Florida, Gainesville, Florida 32611 (Received for publication April 13, 1987)
1988 Poultry Science 67:1302-1305 INTRODUCTION
Precipitated bone phosphate is a byproduct of commercial gelatin production. Bones obtained from the meat packing industry are prepared for gelatin extraction by chipping and being dissolved in hydrochloric acid. After processing is complete, lime is added to the solution and the residual minerals are precipitated out. This precipitated bone product was found by analysis to contain 19.5% phosphorus, 26% calcium, and .28% chloride. The phosphorus shortage of 1973-74 heightened US awareness of the vulnerability of total dependence upon a manufactured product with high energy requirements and limited alternate raw material markets. However, in the last 20 years few new useable alternatives have been offered. Soft, or colloidal, phosphate has been extensively researched and has not been shown to be a satisfactory sole-source phosphorus supplement. Soft phosphate's effectiveness can be enhanced by blending with other sources. Johnson et al. (1953) combined 2% soft phosphate and .5% bone meal with resulting satisfactory growth and bone development in chicks. Summers et al. (1959) enhanced phosphorus
'Florida Agricultural Experiment Station Journal Series Number 8078.
availability from soft phosphate by mixing it either with phosphoric or hydrochloric acids. Results were not as satisfactory with basic steel slag, a byproduct of Thomas Steel manufacturing that contains 8.5% phosphorus (Damron et al., 1983). A significant growth depression and high mortality indicated that this byproduct was not suitable for poultry feeding. Precipitated bone seems to offer promise as a byproduct-source of phosphorus. Miles et al. (1986) provided total phosphorus levels of .55 and 1% using precipitated bone and concluded that it was acceptable in laying hen feeds. The present research was designed to determine performance of precipitated bone as a phosphorus source in broiler chick diets both alone and in combination with soft phosphate. MATERIALS AND METHODS
Duplicate experiments were conducted in Petersime battery brooders (Petersime Incubator Co., Gettysburg, OH), starting with eight, dayold Cobb X Cobb broiler chicks of a single sex allotted to each pen. Three pens of males and three of females received each dietary treatment for a 21-day feeding period. Feed and tap water were provided ad libitum and lighting was continuous. The starter diet of Table 1 was the basis for all diet additions and it was calculated to contain 22.3% CP, 3,100 kcal/kg ME, .92%
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ABSTRACT Day-old Cobb x Cobb broiler chicks were housed in battery brooders for 21-day feeding periods during two experiments. Dietary treatments consisted of a corn-soybean starter feed (.37% total; .14% nonphytin phosphorus) supplemented with 0, .05, .10, .15, or .28% phosphorus in the form of dicalcium phosphate, precipitated bone phosphate, or a mixture of soft and precipitated phosphates (each providing 50% of the phosphorus addition). Total dietary calcium was held constant at .90%. Comparable dietary phosphorus from precipitated bone and the soft-precipitated mixture supported body weights statistically equivalent to those of dicalcium phosphate treatments. Tibia ash results at suboptimal phosphorus levels, with one exception, indicated statistically equal utilization from the soft-precipitated combination. Slope-ratio techniques using tibia ash and total nonphytin phosphorus intake established the bioavailability of phosphorus from precipitated bone was 120% when dicalcium phosphate was the standard. The data indicate that precipitated bone phosphate for broilers was fully equivalent in performance to dicalcium phosphate. Providing one-half the supplemental phosphorus from both soft phosphate and precipitated bone seemed to be an acceptable method of meeting practical phosphorus requirements. {Key words: precipitated bone phosphate, broilers, phosphorus, byproduct sources, growth)
PRECIPITATED BONE PHOSPHATE IN CHICK DIETS TABLE 1. Basal diet composition Ingredients
Percentage
Yellow corn Soybean meal (48.5% protein) Poultry fat Salt Micro ingredients1 DL-Methionine (99%) Filler, phosphate and calcium sources2
55.05 35.50 4.74 .40 .50 .20 3.61
2
Washed builder's sand and ground limestone were the sources of filler and calcium, respectively.
sulfur-containing amino acids, 1.26% lysine, . 10% calcium, and .37% total and. 14% nonphytin phosphorus (National Research Council, 1984). The unsupplemented control diet was given along with four treatments of supplemental phosphorus derived from a commercial dicalcium phosphate, precipitated bone phosphate, or a mixture of soft and precipitated bone sources. The first three supplemental levels (.05, .10, and .15%) were selected to be below the practical requirements, whereas the highest level (.28% supplemental; .65% total) was felt to be adequate for field use. Birds in the soft-precipitated bone treatment series received half their phosphorus supplementation from each of the sources. Calcium levels of all diets were maintained at .90%, with ground limestone. The ground limestone and all three phosphorus sources were analyzed by a commercial laboratory and the results used in formulation. The 3-wk body weights and feed consumption were recorded by pen at the time of experiment termination. Mortality was recorded daily. Calculations of daily feed, phosphorus, and calcium intake were based upon the measurements at the end of the experiment. Tibia ash was measured on the left leg of three birds from each pen. At the termination of the study bones were excised from euthanized chicks, boiled, cleaned of adhering tissue, dried, and ashed at 650 C for 6 h. In order to provide an estimate of phosphorus availability from precipitated bone, a slope-ratio
technique was employed. After it was statistically determined that a linear effect was present and provided best data fit, a regression line of tibia ash (Fx) on the total period intake of nonphytin phosphorus (x) was developed. The resulting regression equation was: Fx = -5971.4698 + 190.2649x; r = .9824. Once the regression line was in place, the amount of nonphytin phosphorus required to produce a tibia ash value comparable to that supported by each of the lower three test phosphate treatments was determined from the line. Predicted nonphytin phosphorus consumption was then divided into the actual intake and the result multiplied by 100 to arrive at a percentage availability value. Performance data were statistically evaluated by ANOVA using the SAS System (SAS Institute Inc., 1979). The statistical model for initial analysis of each experiment included: treatment, sex, and the interaction of treatment and sex in a completely randomized design. The model for combined analysis included the above factors plus experiment and the interaction of treatment and experiment. Mortality data were transformed to arcsine values before analysis. Duncan's multiple range test was used to separate means.
RESULTS AND DISCUSSION
There was no significant treatment X experiment interaction for any criterion except mortality. All data for both experiments except for mortality have been combined in Table 2. Birds receiving all the three series of phosphorus additions responded with growth over the entire range of supplementation (Table 2). Comparable dietary levels of phosphorus from precipitated bone and dicalcium phosphate supported equivalent body weights. The .05% level of supplemental precipitated bone produced significantly higher body weights relative to those resulting from supplementation with .05% dicalcium phosphate. This increase in body weight with precipitated bone was probably related to the 10 mg/day greater phosphorus intake associated with the precipitated bone than from comparable levels of dicalcium phosphate. All levels of the soft-precipitated mixture grew birds to weights statistically comparable to those provided by equivalent dicalcium phosphate treatments. All average body weights from birds fed
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1 Ingredients supplied per kilogram of diet: vitamin A, 6,600 IU; vitamin D 3 , 2,200 ICU; menadione dimethyl-pyrimidinol bisulfite, 2.2 mg; riboflavin, 4.4 mg; pantothenic acid, 13.2 mg; niacin, 39.6 mg; choline chloride, 499.4 mg; vitamin B 1 2 , 22 fig; ethoxyquin, 125 mg; manganese, 60 mg; iron, 50 mg; copper, 6 mg; cobalt, .198 mg; iodine, 1.1 mg; zinc, 35 mg.
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.37 .42 .47 .52 .65
.42 .47 .52 .65
.42 .47 .52 .65
Dicalcium phosphate
Precipitated bone
50% Soft phosphate + 50% precipitated bone
0
.05 .10 .15 .28
.05 .10 .15 .28
.05 .10 .15 .28
K">)
Supplemental
.19 .24 .29 .42
.19 .24 .29 .42
.14 .19 .24 .29 .42
Non-phytin
112 148 184 248
133 163 197 264
83 119 156 204 260
Total
51 75 103 160
61 83 110 170
32 55 79 114 168
mg)
^
Non-phytin (g) 22.5 h 28.8 f S 32.9cde 39.2 a 40.0 a 31.9 d e 34.6 c d 37.8ab 40.6 a 26.78 31.4 e f 35.4 b c 38.2 a
337 f 412 e 485cd 536ab 549 a 454 d 485cd 541a 572 a 410 e 472cd 503bc 536ab
BW
Daily feed intake
Means with no common superscript letters are significantly different according to Duncan's multiple range test
Total
P source
Daily P intake
TABLE 2. Average 21-day body weight, daily feed intake, tibia ash, and mortality dat that received one of three sources of supplemental phosphorus
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PRECIPITATED BONE PHOSPHATE IN CHICK DIETS
was noted in the unsupplemented and .05% dicalcium phosphate treatments. These values resulted in the statistical interaction mentioned earlier and were coupled with reduced feed intake. Results of the present experiment support the findings of Miles et al. (1986); they indicate that precipitated bone phosphate is an acceptable phosphorus source for broilers and fully equivalent in performance to dicalcium phosphate (120% biological availability). The provision of one-half the required supplemental phosphorus from both soft phosphate and precipitated bone phosphate also seemed to be an acceptable method of supplying practical phosphorus requirements in this study. ACKNOWLEDGMENT
The authors wish to express their appreciation to W & S Sales Co., Cleveland, GA for the financial assistance and provision of precipitated bone phosphate that made this study possible. REFERENCES Damron, B. L., E. A. Paz, and L. R. McDowell, 1983. Basic steel slag in the diet of broiler chicks. Nutr. Rep. Int. 27:1315-1322. Johnson, E. L., R. E. Phillips, andG. A. Donovan, 1953. Utilization of soft phosphate with colloidal clay. Poultry Sci. 32:907. (Abstr.) Miles, R. D., A. Rossi, G. Russell, and R. H. Harms, 1986. Performance of laying hens fed phosphorus from precipitated bone. Nutr. Rep. Int. 33:99-104. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. SAS Institute Inc., 1979. SAS User's Guide. SAS Inst. Inc., Raleigh, NC. Summers, J. D., S. J. Slinger, W. F. Pepper, I. Motzok, and G. C. Ashton, 1959. Availability of phosphorus in soft phosphate and phosphoric acid and the effect of acidulation of soft phosphate. Poultry Sci. 38:1168— 1179.
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mixed phosphorus diets were lower than those from dicalcium phosphate, which might have been related to lower daily phosphorus consumption for those groups. In all cases, daily feed intake increased along with phosphorus level (Table 2). No definite patterns in comparable treatments were evident in feed intake measurements for birds receiving suboptimal phosphorus. However, phosphate mixture was associated with intake reductions throughout the suboptimal range of dietary phosphorus. At the adequate phosphorus level of .28%, supplemental (.65% total) intake did not differ significantly. Tibia ash from birds given precipitated bone treatments was statistically equal to that from the birds' counterparts in the dicalcium phosphate series. Birds in one precipitated bone treatment (.15%) responded significantly better than those in its dicalcium phosphate equal. With the exception of the ash value from the .15% phosphorus-soft and precipitated bone mixture treatment, all treatments supported equivalent tibia ash. As noted for body weight, birds receiving .15% phosphorus from the mixture consumed less feed, and 20 mg/day less phosphorus, than their counterparts fed dicalcium phosphate. The results of slope-ratio availability calculations were 123, 108, and 128% for supplemental phosphorus levels of .05,. 10, and .15%, respectively. Based on this outcome, the average phosphorus availability from precipitated bone phosphate was 120% when compared to that from commercial dicalcium phosphate. Mortality was inversely related to phosphorus level in both experiments. In Experiment 1 only moderate mortality occurred, even at the lower levels of supplementation, and none of the means differed significantly. At the conclusion of the second experiment much higher mortality
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