- Email: [email protected]
Effects of Dietary Zinc Supplementation on Broiler Performance and Nitrogen Loss from Manure
Effects of Dietary Zinc Supplementation on Broiler Performance and Nitrogen Loss from Manure W. K. Kim* and P. H. Patterson†,1 *Department of Poultry Science, Texas A&M University, College Station, Texas 77843-2472; and Department of Poultry Science, Pennsylvania State University, University Park, Pennsylvania 16802-3501
(Key words: ammonia volatilization, broiler manure, microbial uricase, uric acid, zinc) 2004 Poultry Science 83:34–38
poultry manure, is converted into allantoin by microbial uricase. The allantoin is further broken down into NH3 by other microbial enzymes (Bacharach, 1957). Therefore, the inhibition of these key enzymes is critical in preventing NH3 volatilization. Kim and Patterson (2003) reported that ZnSO4 significantly inhibited the activity of microbial uricase, reduced NH3 volatilization, and increased nitrogen retention in broiler manure when manure was mixed with up to 2% ZnSO4 (wt/wt). In this study, we hypothesized that, if broiler diets were supplemented with high levels of Zn, uric acid degradation and N loss from manure would be significantly reduced. Therefore, the objectives of this study were as follows: 1) to determine the effect of dietary ZnSO4 or ZnO supplementation on retention of uric acid N and total N in broiler manure and 2) to evaluate the effect of dietary Zn supplementation on broiler performance.
INTRODUCTION As public scrutiny of the environment has increased, the poultry industry has faced pressure to reduce its impact on the environment. One of the major environmental concerns associated with the poultry industry is NH3 volatilization, which increases atmospheric acid deposition (Moore, 1998). Many studies have demonstrated that high levels of NH3 on the farm could reduce feed efficiency, growth rate, and egg production (Charles and Payne, 1966; Reece et al., 1980; Caveny et al., 1981; Deaton et al., 1984); damage the respiratory tract (Nagaraja et al., 1983); and impair immune responses (Nagaraja et al., 1984). Thus, reducing NH3 volatilization is very important to maintain human and animal health and a clean environment. Ammonia losses from poultry manure are enhanced by microbial activity. Uric acid, the dominant N form in
MATERIALS AND METHODS There were 8 dietary treatments: the control, CuSO420, ZnSO4-500, ZnSO4-1,000, ZnSO4-1,500, ZnO-500, ZnO1,000, and ZnO-1,500. The formulation of the control diet is shown in Table 1. The Zn treatments contained 500,
2004 Poultry Science Association, Inc. Received for publication March 6, 2003. Accepted for publication September 9, 2003. 1 To whom correspondence should be addressed: [email protected].
34
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
feed consumption, and feed efficiency of chicks fed the diets supplemented with 1,500 ppm Zn as ZnSO4 were significantly lower than those of the other treatments, whereas the ZnO treatments had no negative effects on growth performance. After the 21-d incubation, the uric acid-N levels of manure from chicks fed the ZnO-1,000 treatment were significantly higher than those of manure from chicks fed the ZnSO4-500. The manure from chicks fed the Zn-supplemented diets had significantly less total N loss compared with that from chicks fed the control. The manure from chicks fed ZnO-1,500 had significantly less total N loss than that from chicks fed the other treatment diets. This study indicated that the Zn treatments significantly reduced nitrogen loss in poultry manure, and ZnO could be a better Zn source to prevent nitrogen loss to the atmosphere without any detrimental effect on growth performance.
ABSTRACT An experiment was conducted to evaluate the effects of ZnSO4 or ZnO supplementation of broiler diets on growth performance and loss of uric acid N and total N from manure. A total of 240, 1-d-old broiler males were used for this experiment. Each dietary treatment was replicated 3 times with 10 birds per replicate. Chicks were fed a control diet for the first 6 d and then treatment diets for the next 12 d. There were 8 dietary treatments: the control, CuSO4-20, ZnSO4-500, ZnSO4-1,000, ZnSO41,500, ZnO-500, ZnO-1,000, and ZnO-1,500 containing 0, 0, 500, 1,000, 1,500 ppm supplemental Zn as ZnSO4 and 500, 1,000, and 1,500 ppm supplemental Zn as ZnO, respectively. A 300-g sample of the broiler manure from each treatment was incubated in a pan for 3 wk at room temperature. After incubation, samples were collected for the measurement of total N and uric acid N. Weight gain,
35
ZINC AND NITROGEN LOSS IN MANURE TABLE 1. Control broiler diet Ingredient Corn Soybean meal (48% CP) Poultry by-product Bakery product Fat Phosphorus Liquid methionine Limestone Lysine Trace mineral mix1 Maxiban2 Vitamin mix3 Choline Crude protein Metabolizable energy
53.45 28.08 9.01 7.51 0.50 0.40 0.39 0.30 0.17 0.05 0.05 0.05 0.05 23.48 3,112 kcal/kg Analyzed Zn level (ppm) 112 105 679 1,179 1,697 663 1,183 1,611
1 Trace mineral mix = Mn, 120,000 ppm; Fe, 100,000 ppm; Cu 10,000 ppm; Zn, 110,000 ppm; I, 2,400 ppm; Se, 600 ppm. 2 Maxiban = a mixture of the compounds of Nicarbazin and Narasin to prevent coccidiosis caused by Eimeria necatrix, Eimeria tenella, Eimeria acervulina, Eimeria brunetti, Eimeria mivati, and Eimeria maxima. 3 Vitamin mix = vitamin A, 8,000 KIU; vitamin E, 20,000 IU; riboflavin, 5,500 mg; pantothenic acid, 10,000 mg; niacin, 40,000 mg; folic acid, 600 mg; thiamine, 1,200 mg; pyridoxine, 2,000 mg; biotin, 50,000 µg; vitamin B12, 12,000 µg; vitamin D3, 3,000 KIU. 4 Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO1000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4.
1,000, or 1,500 ppm Zn as ZnSO4 or ZnO and an extra 20 ppm of Cu as CuSO4 to prevent a Cu deficiency due to high Zn supplementation. The CuSO4-20 treatment was supplemented with 20 ppm of Cu as CuSO4. A total of 240 1-d-old broiler males were used for this experiment. Each dietary treatment was replicated 3 times with 10 birds per replicate. Chicks were fed the control diet for the first 6 d and then treatment diets for the next 12 d. Manure was collected daily from d 8 to 18 and immediately frozen at −20°C for the analysis of Zn, uric acid N, and total N concentrations and for subsequent incubation experiments. Body weight and feed consumption were measured on d 6, 9, 12, 15, and 18. On d 18, 2 birds from each treatment were killed by cervical dislocation, and the breast muscle was collected for the measurement of mineral concentrations. A 300-g sample of the broiler manure was removed from freezer storage and incubated in a pan for 3 wk at room temperature. After incubation, samples were collected for the measurement of total N, uric acid N, and mineral concentration using a combustion method
(AOAC, 1994), a colorimetric method (Alumot and Bielorai, 1979), and an ICP method (USEPA, 1986), respectively. All animal care procedures were carried out as described in the protocol approved by the Pennsylvania State University Institutional Animal Care and Use Committee (00R007-00).
Statistical Analysis The data from all experiments were subjected to oneway ANOVA as a completely randomized design using the general linear models procedure of SAS software (SAS Institute, 1994). Significant differences among the means were determined by using Duncan’s multiple-range test (Duncan, 1955) at P < 0.05.
RESULTS The impact of dietary ZnSO4 or ZnO supplementation on broiler growth performance during the entire experiment period (d 6 to 18) is shown in Table 2. The weight gain of chicks fed the ZnSO4-1,500 was significantly lower than that of chicks fed the control and other treatments. The chicks on ZnO treatment had greater weight gains than those fed the ZnSO4-1,000 or 1,500 treatments (P < 0.05), whereas there were no significant differences in weight gain among the control and ZnO treatments. Increasing dietary Zn levels as ZnSO4 from 500 to 1,500 ppm decreased the weight gain; however, the chicks fed ZnO treatments did not exhibit this trend. Feed consumption of chicks fed the ZnSO4-1,000 or ZnSO4 -1,500 diet was significantly lower than for those fed the control, ZnO-500, ZnO-1,000, or CuSO4-20 diet. Feed consumption decreased linearly with dietary Zn levels as supplemental ZnSO4 increased from 500 to 1,500 ppm. However, there were no significant differences in feed consumption among chicks fed the control, the ZnSO4-500, the 3 ZnO treatments, or the CuSO4-20 diet. Feed efficiencies of chicks fed the ZnSO4-1,500 or CuSO420 treatment were lower than for those fed the ZnO-1,000 treatment (P < 0.05), whereas there were no significant feed efficiency differences among chicks fed the control and the other treatments. The Zn and Cu levels of manure and breast muscle from chicks fed different levels of Zn are shown in Table 3. The overall trend for Zn excretion was that Zn levels in manure increased as dietary Zn levels increased. The manure from chicks fed the ZnO-1,500 treatment contained a significantly higher amount of Zn than that of chicks fed the other treatments, whereas the manure from chicks fed the control and CuSO4-20 had significantly less. Copper levels in the manure of chicks fed the ZnO500 treatment were significantly higher than those in the manure of chicks fed ZnSO4-1,000, ZnSO4-1,500, ZnO1,000, and CuSO4-20 diets. The manure from chicks fed the control diet had significantly lower levels than the other treatments because the control diet did not contain the additional 20 ppm of Cu from CuSO4 that was present in the other dietary treatments. The manure from chicks
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
Treatment4 Control CuSO4-20 ZnSO4-500 ZnSO4-1000 ZnSO4-1500 ZnO-500 ZnO-1000 ZnO-1500
%
36
KIM AND PATTERSON TABLE 2. Weight gain, feed consumption, and feed efficiency of chicks fed different levels of ZnSO4 or ZnO from d 6 to 18 Treatment1
Weight gain2 (g/cage)
Feed consumption2 (g/cage)
Feed efficiency2 (g gain/g feed)
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SE
511abc 497bc 504abc 481c 436d 524ab 538a 511abc 8.79
779a 788a 766ab 733bc 696c 804a 784a 775ab 12.81
0.66ab 0.63b 0.66ab 0.66ab 0.63b 0.65ab 0.69a 0.66ab 0.09
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 cages per mean (10 birds per cage) for weight gain, feed consumption, and feed efficiency. a-d 1
to 1,500 ppm reduced the losses of manure uric acid N after 21 d of incubation, there were no significant differences in the loss of uric acid N after incubation among the treatments. Manure total N levels on d 0 and 21 were not significantly different among the treatments. However, there were significant differences in the losses of manure total N before and after 21 d of incubation; the manure from chicks fed the Zn-treated diets had significantly less total N loss compared with manure from those fed the control diet. The manure from chicks fed the ZnO-1,500 diet had significantly less total N loss after 21-d incubation than that from chicks fed the other treatment diets. Manure pH levels from chicks fed different levels of Zn from ZnSO4 or ZnO before and after a 21-d incubation are shown in Table 5. Before the incubation, the manure pH levels of chicks fed the ZnSO4-1,500 (6.51) and ZnO-
TABLE 3. Mineral concentrations of manure and breast muscle from chicks fed different levels of ZnSO4 or ZnO (DM basis) Manure2 Treatment Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SE
Breast muscle3
Zn (ppm)
Cu (ppm)
Zn (ppm)
400e 430e 2,192d 4,282c 5,486b 2,357d 4,069c 6,357a 73.51
47d 113b 121ab 115b 103c 128a 114b 123ab 2.88
26.4 26.6 25.9 27.0 25.6 25.7 25.7 27.7 0.03
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. The manure from a pen on d 18 was a replicate. 3 n = 3 per mean. The breast muscle from 2 birds of a pen on d 18 was a replicate. a-e 1
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
fed the ZnSO4-1,500 treatment had significantly less Cu than that from chicks fed the other Zn treatments. The Zn levels of breast muscle were not significantly different among the treatments. Cu levels in breast muscle were not detectable. Although Fe, P, and K levels were also measured, the dietary Zn treatments did not significantly affect their concentrations in manure or breast muscle. The contents of uric acid N and total N in the manure from chicks fed the different levels of Zn from ZnSO4 or ZnO before and after 21 d of incubation are shown in Table 4. On d 0, there were no significant differences in uric acid N among the treatments. However, after the 21d incubation, the manure from chicks fed the ZnO-1,000 treatments had significantly higher uric acid N levels compared with the manure from those fed the ZnSO4500 diet. Although increasing dietary Zn levels from 500
37
ZINC AND NITROGEN LOSS IN MANURE TABLE 4. Contents of uric acid N and total N in manure from chicks fed different levels of ZnSO4 or ZnO before and after a 21-d incubation (DM basis) Uric acid N (g) 1,2
Treatment
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SEM
Day 0 4.98 4.25 3.79 4.32 5.14 5.08 5.81 4.80 0.51
Day 21
Total N difference
Day 0
Day 21
Difference
1.56 1.08 0.85 0.94 0.99 1.49 1.18 0.69 0.32
8.97 7.49 7.26 8.30 8.79 7.87 9.00 7.26 0.58
7.30 6.82 6.62 7.31 8.03 7.34 8.48 7.15 0.60
1.68a 0.66bc 0.63bc 0.99b 0.75bc 0.52c 0.52c 0.11d 0.11
ab
3.42 3.17ab 2.94b 3.58ab 4.15ab 3.59ab 4.53a 4.11ab 0.40
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. A subsample of the mixed manure from a treatment was a replicate. a-d 1
DISCUSSION The results of the present study indicated that 1,500 ppm of Zn supplementation as ZnSO4 reduced BW, feed consumption, and feed efficiency compared with the other treatments; however, the ZnO treatments did not depress broiler performance. One of the reasons for the TABLE 5. Manure pH from chicks fed different levels of ZnSO4 or ZnO before and after a 21-d incubation Treatment1
Day 02
Day 212
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SEM
7.22ab 6.73ab 6.47ab 7.02ab 6.51b 6.53b 7.15ab 7.51a 0.22
6.48 6.27 6.29 6.51 6.37 6.26 6.60 6.56 0.18
a,b Means within a column with different superscripts differ significantly (P < 0.05). 1 Control = chicks fed commercial broiler starter diet; CuSO4-20 = chicks fed commercial broiler starter diet supplemented with 20 ppm Cu from CuSO4; ZnSO4-500 = chicks fed commercial broiler starter diet supplemented with 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = chicks fed commercial broiler starter diet supplemented with 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO41,500 = chicks fed commercial broiler starter diet supplemented with 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = chicks fed commercial broiler starter diet supplemented with 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = chicks fed commercial broiler starter diet supplemented with 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = chicks fed commercial broiler starter diet supplemented with 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. A subsample of the mixed manure from a treatment was a replicate.
differences in BW and feed consumption could be the bioavailabilities of Zn sources. Highly available Zn sources are more toxic when consumed at high levels (Sandoval et al., 1998), and Sandoval et al. (1997) and Ammerman et al. (1998) indicated that ZnO was less bioavailable relative to ZnSO4. Findings of the study reported herein are in agreement with other studies. Roberson and Schaible (1960) indicated that 1,500 ppm of ZnSO4 supplementation depressed broiler growth, whereas this level of ZnO was tolerated to a greater degree than that of the sulfate or carbonate forms. Sandoval et al. (1998) also reported that the feed intake and BW of chicks fed 1,500 ppm Zn as ZnSO4 were significantly depressed compared with those of chicks fed 0, 500, or 1,000 ppm Zn as ZnSO4. However, dietary supplementation of Zn as ZnO did not show any detrimental effect on broiler performance (Roberson and Schaible, 1960; Johnson et al., 1962; Sandoval et al. 1997). Zinc excretion in the manure increased linearly as dietary Zn levels increased. The Zn levels of manure were concentrated approximately 4-fold greater than dietary levels. However, birds fed the 1,500 ppm ZnO treatment excreted significantly more Zn (16%) than birds fed the same level of Zn as ZnSO4 (Sandoval et al., 1997; Ammerman et al., 1998). This finding could also be due to the bioavailability of Zn sources. Because the bioavailability of ZnO is lower than that of ZnSO4, birds fed the 1,500 ppm ZnO treatment excreted significantly more Zn than those fed 1,500 ppm ZnSO4. The Zn levels in breast muscle were not significantly different among the treatments, and there were no other trends in muscle mineral concentration influenced by dietary Zn levels. Sandoval et al. (1998) evaluated the effect of dietary Zn on tissue concentrations in chicks and indicated increasing dietary Zn supplementation resulted in increased Zn concentration in bone, liver, kidney, and muscle. However, they also indicated that the muscle Zn concentration was less sensitive to dietary Zn changes
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
500 (6.53) diets were significantly lower than those in manure from chicks fed the ZnO-1,500 (7.51) diet. However, after 21 d of incubation, there were no significant differences in pH among the treatments.
38
KIM AND PATTERSON
REFERENCES Alumot, E., and R. Bielorai. 1979. Colorimetric determination of uric acid in poultry excreta. J. Assoc. Off. Anal. Chem. 62:1350–1352. Ammerman, C. B., P. R. Henry, and R. D. Miles. 1998. Supplemental organically-bound mineral compounds in livestock
nutrition. Pages 67–91 in Recent Advances in Animal Nutrition. P. C. Garnsworthy and J. Wisemane, ed. Nottingham University Press, Nottingham, UK. AOAC. 1994. Official Methods of Analysis. 16th ed. Association of Official Analytical Chemists. Washington, D.C. Bacharach, U. 1957. The aerobic breakdown of uric acid by certain pseudomonads. J. Gen. Microbiol. 17:1–11. Bongaerts, G. P. A., J. Uitzetter, R. Brouns, and G. D. Vogels. 1978. Uricase of Bacillus fastidiosus properties and regulation of synthesis. Biochim. Biophys. Acta 527:348–358. Caveny, D. D., C. L. Quarles, and G. A. Greathouse. 1981. Atmospheric ammonia and broiler performance and carcass quality. Poult. Sci. 57:1124–1125. Charles, D. R., and C. G. Payne. 1966. The influence of graded levels of atmospheric ammonia on chickens. I. Effects on respiration and on the performance of broilers and replacement growing stock. Br. Poult. Sci. 7:177–187. Deaton, J. W., F. N. Reece, and B. D. Lott. 1984. Effect of atmospheric ammonia on pullets at point of lay. Poult. Sci. 63:384–385. Duncan, D. B. 1955. Multiple range and multiple F-test. Biometrics 11:1–42. Johnson, D., Jr., A. L. Mehring, Jr., F. X. Savino, and H. W. Titus. 1962. The tolerance of growing chickens for dietary zinc. Poult. Sci. 41:311–317. Kim, W. K., and P. H. Patterson. 2003. Effects of minerals on activity of microbial uricase to reduce ammonia volatilization in poultry manure. Poult. Sci. 82:223–231. Moore, P. A., Jr. 1998. Best management practices for poultry manure utilization that enhance agricultural productivity and reduce pollution. Pages 89–117 in Animal Waste Utilization: Effective Use of Manure as a Soil Resource. J. L. Hatfield and B. Stewart, ed. Ann Arbor Press, Chelsea, MI. Nagaraja, K. V., D. A. Emery, K. A. Jordan, V. Sivanandan, J. A. Newman, and B. S. Pomeroy. 1983. Scanning electron microscopic studies of adverse effects of ammonia on tracheal tissues of turkeys. Am. J. Vet. Res. 44:1530–1536. Nagaraja, K. V., D. A. Emery, K. A. Jordan, V. Sivanandan, J. A. Newman, and B. S. Pomeroy. 1984. Effect of ammonia on the quantitative clearance of Escherichia coli from lungs, air sacs, and livers of turkey aerosol vaccinated against Escherichia coli. Am. J. Vet. Res. 45:392–395. Reece, F. N., B. D. Lott, and J. W. Deaton. 1980. Ammonia in the atmosphere during brooding affects performance of broiler chickens. Poult. Sci. 59:486–488. Roberson, R. H., and P. J. Schaible. 1960. The tolerance of growing chicks for high levels of different forms of zinc. Poult. Sci. 39:893–896. SAS. 1994. SAS/STAT User’s Guide: Statistics, Release 6.08. SAS Institute Inc., Cary, NC. Sandoval, M., P. R. Henry, C. B. Ammerman, R. D. Miles, and R. C. Littell. 1997. Relative bioavailability of supplemental inorganic zinc sources for chicks. J. Anim. Sci. 75:3195–3205. Sandoval, M., P. R. Henry, X. G. Luo, R. C. Littell, R. D. Miles, and C. B. Ammerman. 1998. Performance and tissue zinc and metallothionein accumulation in chicks fed a high dietary level of zinc. Poult. Sci. 77:1354–1363. U.S. Environmental Protection Agency (USEPA). 1986. Test Methods for Evaluating Solid Waste. Vol. 1A. 3rd ed. EPA/ SW-846. National Technical Information Service, Springfield, VA.
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
than other tissues. They estimated the linear regression of tissue Zn concentrations with dietary Zn concentration. In their model, muscle Zn was found to have a poor fit (r2 = 0.04) compared with the other tissues, such as bone (r2 = 0.99), liver (r2 = 0.79), and kidney (r2 = 0.76). They also showed that dietary Zn supplementation had little effect on the concentrations of other tissue minerals. The Zn supplementation herein significantly reduced the loss of manure total N after the 21-d manure incubation compared with that of chicks fed the control diet. In the present study, however, Zn not only appears to inhibit the activity of microbial uricase but also to reduce the activities of other microbial enzymes related to ammonia production in poultry manure. There are 5 enzymatic steps in aerobic degradation of uric acid (Bacharach, 1957; Bongaerts et al., 1978). First, uricase converts uric acid into allantoin. Second, allantoin is converted into allantoic acid by allantoinase. Third, allantoic acid is converted into ureidoglycolate by allantoate amidohydrolase. Fourth, ureidoglycolate is converted into glyoxylate and urea by ureidoglycolase, and finally, urea is hydrolyzed into ammonia and CO2 by urease. The Zn treatments herein might influence these 5 enzymes, increasing the retention of intermediate components of uric acid. Although there were significant differences in the losses of total N after 21 d of incubation, the total N loss after 21 d of incubation was relatively lower. One of the possible reasons why total N loss was low could have been due to low manure moisture and pH levels. The initial manure samples were not moist, and manure samples quickly dried during the 3-wk incubation. Although the sample manure was collected and frozen daily during the 3-wk feeding trial, the chicks consumed a small amount of feed, producing little manure, and the brooder heating element dried the manure in the collecting trays. Furthermore, the dry manure most likely affected pH level, preventing ammonia N volatilization. The pH of the manure on d 21 in the present study was approximately 6.5, which was much lower than the normal pH of 3-wk-old broiler manure (approximately 9). This low pH in the manure of the present study may have reduced ammonia loss from the manure, diminishing differences in total N among the control and the Zn treatments.
(Key words: ammonia volatilization, broiler manure, microbial uricase, uric acid, zinc) 2004 Poultry Science 83:34–38
poultry manure, is converted into allantoin by microbial uricase. The allantoin is further broken down into NH3 by other microbial enzymes (Bacharach, 1957). Therefore, the inhibition of these key enzymes is critical in preventing NH3 volatilization. Kim and Patterson (2003) reported that ZnSO4 significantly inhibited the activity of microbial uricase, reduced NH3 volatilization, and increased nitrogen retention in broiler manure when manure was mixed with up to 2% ZnSO4 (wt/wt). In this study, we hypothesized that, if broiler diets were supplemented with high levels of Zn, uric acid degradation and N loss from manure would be significantly reduced. Therefore, the objectives of this study were as follows: 1) to determine the effect of dietary ZnSO4 or ZnO supplementation on retention of uric acid N and total N in broiler manure and 2) to evaluate the effect of dietary Zn supplementation on broiler performance.
INTRODUCTION As public scrutiny of the environment has increased, the poultry industry has faced pressure to reduce its impact on the environment. One of the major environmental concerns associated with the poultry industry is NH3 volatilization, which increases atmospheric acid deposition (Moore, 1998). Many studies have demonstrated that high levels of NH3 on the farm could reduce feed efficiency, growth rate, and egg production (Charles and Payne, 1966; Reece et al., 1980; Caveny et al., 1981; Deaton et al., 1984); damage the respiratory tract (Nagaraja et al., 1983); and impair immune responses (Nagaraja et al., 1984). Thus, reducing NH3 volatilization is very important to maintain human and animal health and a clean environment. Ammonia losses from poultry manure are enhanced by microbial activity. Uric acid, the dominant N form in
MATERIALS AND METHODS There were 8 dietary treatments: the control, CuSO420, ZnSO4-500, ZnSO4-1,000, ZnSO4-1,500, ZnO-500, ZnO1,000, and ZnO-1,500. The formulation of the control diet is shown in Table 1. The Zn treatments contained 500,
2004 Poultry Science Association, Inc. Received for publication March 6, 2003. Accepted for publication September 9, 2003. 1 To whom correspondence should be addressed: [email protected].
34
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
feed consumption, and feed efficiency of chicks fed the diets supplemented with 1,500 ppm Zn as ZnSO4 were significantly lower than those of the other treatments, whereas the ZnO treatments had no negative effects on growth performance. After the 21-d incubation, the uric acid-N levels of manure from chicks fed the ZnO-1,000 treatment were significantly higher than those of manure from chicks fed the ZnSO4-500. The manure from chicks fed the Zn-supplemented diets had significantly less total N loss compared with that from chicks fed the control. The manure from chicks fed ZnO-1,500 had significantly less total N loss than that from chicks fed the other treatment diets. This study indicated that the Zn treatments significantly reduced nitrogen loss in poultry manure, and ZnO could be a better Zn source to prevent nitrogen loss to the atmosphere without any detrimental effect on growth performance.
ABSTRACT An experiment was conducted to evaluate the effects of ZnSO4 or ZnO supplementation of broiler diets on growth performance and loss of uric acid N and total N from manure. A total of 240, 1-d-old broiler males were used for this experiment. Each dietary treatment was replicated 3 times with 10 birds per replicate. Chicks were fed a control diet for the first 6 d and then treatment diets for the next 12 d. There were 8 dietary treatments: the control, CuSO4-20, ZnSO4-500, ZnSO4-1,000, ZnSO41,500, ZnO-500, ZnO-1,000, and ZnO-1,500 containing 0, 0, 500, 1,000, 1,500 ppm supplemental Zn as ZnSO4 and 500, 1,000, and 1,500 ppm supplemental Zn as ZnO, respectively. A 300-g sample of the broiler manure from each treatment was incubated in a pan for 3 wk at room temperature. After incubation, samples were collected for the measurement of total N and uric acid N. Weight gain,
35
ZINC AND NITROGEN LOSS IN MANURE TABLE 1. Control broiler diet Ingredient Corn Soybean meal (48% CP) Poultry by-product Bakery product Fat Phosphorus Liquid methionine Limestone Lysine Trace mineral mix1 Maxiban2 Vitamin mix3 Choline Crude protein Metabolizable energy
53.45 28.08 9.01 7.51 0.50 0.40 0.39 0.30 0.17 0.05 0.05 0.05 0.05 23.48 3,112 kcal/kg Analyzed Zn level (ppm) 112 105 679 1,179 1,697 663 1,183 1,611
1 Trace mineral mix = Mn, 120,000 ppm; Fe, 100,000 ppm; Cu 10,000 ppm; Zn, 110,000 ppm; I, 2,400 ppm; Se, 600 ppm. 2 Maxiban = a mixture of the compounds of Nicarbazin and Narasin to prevent coccidiosis caused by Eimeria necatrix, Eimeria tenella, Eimeria acervulina, Eimeria brunetti, Eimeria mivati, and Eimeria maxima. 3 Vitamin mix = vitamin A, 8,000 KIU; vitamin E, 20,000 IU; riboflavin, 5,500 mg; pantothenic acid, 10,000 mg; niacin, 40,000 mg; folic acid, 600 mg; thiamine, 1,200 mg; pyridoxine, 2,000 mg; biotin, 50,000 µg; vitamin B12, 12,000 µg; vitamin D3, 3,000 KIU. 4 Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO1000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4.
1,000, or 1,500 ppm Zn as ZnSO4 or ZnO and an extra 20 ppm of Cu as CuSO4 to prevent a Cu deficiency due to high Zn supplementation. The CuSO4-20 treatment was supplemented with 20 ppm of Cu as CuSO4. A total of 240 1-d-old broiler males were used for this experiment. Each dietary treatment was replicated 3 times with 10 birds per replicate. Chicks were fed the control diet for the first 6 d and then treatment diets for the next 12 d. Manure was collected daily from d 8 to 18 and immediately frozen at −20°C for the analysis of Zn, uric acid N, and total N concentrations and for subsequent incubation experiments. Body weight and feed consumption were measured on d 6, 9, 12, 15, and 18. On d 18, 2 birds from each treatment were killed by cervical dislocation, and the breast muscle was collected for the measurement of mineral concentrations. A 300-g sample of the broiler manure was removed from freezer storage and incubated in a pan for 3 wk at room temperature. After incubation, samples were collected for the measurement of total N, uric acid N, and mineral concentration using a combustion method
(AOAC, 1994), a colorimetric method (Alumot and Bielorai, 1979), and an ICP method (USEPA, 1986), respectively. All animal care procedures were carried out as described in the protocol approved by the Pennsylvania State University Institutional Animal Care and Use Committee (00R007-00).
Statistical Analysis The data from all experiments were subjected to oneway ANOVA as a completely randomized design using the general linear models procedure of SAS software (SAS Institute, 1994). Significant differences among the means were determined by using Duncan’s multiple-range test (Duncan, 1955) at P < 0.05.
RESULTS The impact of dietary ZnSO4 or ZnO supplementation on broiler growth performance during the entire experiment period (d 6 to 18) is shown in Table 2. The weight gain of chicks fed the ZnSO4-1,500 was significantly lower than that of chicks fed the control and other treatments. The chicks on ZnO treatment had greater weight gains than those fed the ZnSO4-1,000 or 1,500 treatments (P < 0.05), whereas there were no significant differences in weight gain among the control and ZnO treatments. Increasing dietary Zn levels as ZnSO4 from 500 to 1,500 ppm decreased the weight gain; however, the chicks fed ZnO treatments did not exhibit this trend. Feed consumption of chicks fed the ZnSO4-1,000 or ZnSO4 -1,500 diet was significantly lower than for those fed the control, ZnO-500, ZnO-1,000, or CuSO4-20 diet. Feed consumption decreased linearly with dietary Zn levels as supplemental ZnSO4 increased from 500 to 1,500 ppm. However, there were no significant differences in feed consumption among chicks fed the control, the ZnSO4-500, the 3 ZnO treatments, or the CuSO4-20 diet. Feed efficiencies of chicks fed the ZnSO4-1,500 or CuSO420 treatment were lower than for those fed the ZnO-1,000 treatment (P < 0.05), whereas there were no significant feed efficiency differences among chicks fed the control and the other treatments. The Zn and Cu levels of manure and breast muscle from chicks fed different levels of Zn are shown in Table 3. The overall trend for Zn excretion was that Zn levels in manure increased as dietary Zn levels increased. The manure from chicks fed the ZnO-1,500 treatment contained a significantly higher amount of Zn than that of chicks fed the other treatments, whereas the manure from chicks fed the control and CuSO4-20 had significantly less. Copper levels in the manure of chicks fed the ZnO500 treatment were significantly higher than those in the manure of chicks fed ZnSO4-1,000, ZnSO4-1,500, ZnO1,000, and CuSO4-20 diets. The manure from chicks fed the control diet had significantly lower levels than the other treatments because the control diet did not contain the additional 20 ppm of Cu from CuSO4 that was present in the other dietary treatments. The manure from chicks
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
Treatment4 Control CuSO4-20 ZnSO4-500 ZnSO4-1000 ZnSO4-1500 ZnO-500 ZnO-1000 ZnO-1500
%
36
KIM AND PATTERSON TABLE 2. Weight gain, feed consumption, and feed efficiency of chicks fed different levels of ZnSO4 or ZnO from d 6 to 18 Treatment1
Weight gain2 (g/cage)
Feed consumption2 (g/cage)
Feed efficiency2 (g gain/g feed)
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SE
511abc 497bc 504abc 481c 436d 524ab 538a 511abc 8.79
779a 788a 766ab 733bc 696c 804a 784a 775ab 12.81
0.66ab 0.63b 0.66ab 0.66ab 0.63b 0.65ab 0.69a 0.66ab 0.09
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 cages per mean (10 birds per cage) for weight gain, feed consumption, and feed efficiency. a-d 1
to 1,500 ppm reduced the losses of manure uric acid N after 21 d of incubation, there were no significant differences in the loss of uric acid N after incubation among the treatments. Manure total N levels on d 0 and 21 were not significantly different among the treatments. However, there were significant differences in the losses of manure total N before and after 21 d of incubation; the manure from chicks fed the Zn-treated diets had significantly less total N loss compared with manure from those fed the control diet. The manure from chicks fed the ZnO-1,500 diet had significantly less total N loss after 21-d incubation than that from chicks fed the other treatment diets. Manure pH levels from chicks fed different levels of Zn from ZnSO4 or ZnO before and after a 21-d incubation are shown in Table 5. Before the incubation, the manure pH levels of chicks fed the ZnSO4-1,500 (6.51) and ZnO-
TABLE 3. Mineral concentrations of manure and breast muscle from chicks fed different levels of ZnSO4 or ZnO (DM basis) Manure2 Treatment Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SE
Breast muscle3
Zn (ppm)
Cu (ppm)
Zn (ppm)
400e 430e 2,192d 4,282c 5,486b 2,357d 4,069c 6,357a 73.51
47d 113b 121ab 115b 103c 128a 114b 123ab 2.88
26.4 26.6 25.9 27.0 25.6 25.7 25.7 27.7 0.03
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. The manure from a pen on d 18 was a replicate. 3 n = 3 per mean. The breast muscle from 2 birds of a pen on d 18 was a replicate. a-e 1
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
fed the ZnSO4-1,500 treatment had significantly less Cu than that from chicks fed the other Zn treatments. The Zn levels of breast muscle were not significantly different among the treatments. Cu levels in breast muscle were not detectable. Although Fe, P, and K levels were also measured, the dietary Zn treatments did not significantly affect their concentrations in manure or breast muscle. The contents of uric acid N and total N in the manure from chicks fed the different levels of Zn from ZnSO4 or ZnO before and after 21 d of incubation are shown in Table 4. On d 0, there were no significant differences in uric acid N among the treatments. However, after the 21d incubation, the manure from chicks fed the ZnO-1,000 treatments had significantly higher uric acid N levels compared with the manure from those fed the ZnSO4500 diet. Although increasing dietary Zn levels from 500
37
ZINC AND NITROGEN LOSS IN MANURE TABLE 4. Contents of uric acid N and total N in manure from chicks fed different levels of ZnSO4 or ZnO before and after a 21-d incubation (DM basis) Uric acid N (g) 1,2
Treatment
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SEM
Day 0 4.98 4.25 3.79 4.32 5.14 5.08 5.81 4.80 0.51
Day 21
Total N difference
Day 0
Day 21
Difference
1.56 1.08 0.85 0.94 0.99 1.49 1.18 0.69 0.32
8.97 7.49 7.26 8.30 8.79 7.87 9.00 7.26 0.58
7.30 6.82 6.62 7.31 8.03 7.34 8.48 7.15 0.60
1.68a 0.66bc 0.63bc 0.99b 0.75bc 0.52c 0.52c 0.11d 0.11
ab
3.42 3.17ab 2.94b 3.58ab 4.15ab 3.59ab 4.53a 4.11ab 0.40
Means within a column with different superscripts differ significantly (P < 0.05). Control = commercial broiler starter diet; CuSO4-20 = control diet + 20 ppm Cu from CuSO4; ZnSO4-500 = control diet + 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = control diet + 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,500 = control diet + 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = control diet + 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = control diet + 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1500 = control diet + 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. A subsample of the mixed manure from a treatment was a replicate. a-d 1
DISCUSSION The results of the present study indicated that 1,500 ppm of Zn supplementation as ZnSO4 reduced BW, feed consumption, and feed efficiency compared with the other treatments; however, the ZnO treatments did not depress broiler performance. One of the reasons for the TABLE 5. Manure pH from chicks fed different levels of ZnSO4 or ZnO before and after a 21-d incubation Treatment1
Day 02
Day 212
Control CuSO4-20 ZnSO4-500 ZnSO4-1,000 ZnSO4-1,500 ZnO-500 ZnO-1,000 ZnO-1,500 Pooled SEM
7.22ab 6.73ab 6.47ab 7.02ab 6.51b 6.53b 7.15ab 7.51a 0.22
6.48 6.27 6.29 6.51 6.37 6.26 6.60 6.56 0.18
a,b Means within a column with different superscripts differ significantly (P < 0.05). 1 Control = chicks fed commercial broiler starter diet; CuSO4-20 = chicks fed commercial broiler starter diet supplemented with 20 ppm Cu from CuSO4; ZnSO4-500 = chicks fed commercial broiler starter diet supplemented with 500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO4-1,000 = chicks fed commercial broiler starter diet supplemented with 1,000 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnSO41,500 = chicks fed commercial broiler starter diet supplemented with 1,500 ppm Zn from ZnSO4 + 20 ppm Cu from CuSO4; ZnO-500 = chicks fed commercial broiler starter diet supplemented with 500 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,000 = chicks fed commercial broiler starter diet supplemented with 1,000 ppm Zn from ZnO + 20 ppm Cu from CuSO4; ZnO-1,500 = chicks fed commercial broiler starter diet supplemented with 1,500 ppm Zn from ZnO + 20 ppm Cu from CuSO4. 2 n = 3 per mean. A subsample of the mixed manure from a treatment was a replicate.
differences in BW and feed consumption could be the bioavailabilities of Zn sources. Highly available Zn sources are more toxic when consumed at high levels (Sandoval et al., 1998), and Sandoval et al. (1997) and Ammerman et al. (1998) indicated that ZnO was less bioavailable relative to ZnSO4. Findings of the study reported herein are in agreement with other studies. Roberson and Schaible (1960) indicated that 1,500 ppm of ZnSO4 supplementation depressed broiler growth, whereas this level of ZnO was tolerated to a greater degree than that of the sulfate or carbonate forms. Sandoval et al. (1998) also reported that the feed intake and BW of chicks fed 1,500 ppm Zn as ZnSO4 were significantly depressed compared with those of chicks fed 0, 500, or 1,000 ppm Zn as ZnSO4. However, dietary supplementation of Zn as ZnO did not show any detrimental effect on broiler performance (Roberson and Schaible, 1960; Johnson et al., 1962; Sandoval et al. 1997). Zinc excretion in the manure increased linearly as dietary Zn levels increased. The Zn levels of manure were concentrated approximately 4-fold greater than dietary levels. However, birds fed the 1,500 ppm ZnO treatment excreted significantly more Zn (16%) than birds fed the same level of Zn as ZnSO4 (Sandoval et al., 1997; Ammerman et al., 1998). This finding could also be due to the bioavailability of Zn sources. Because the bioavailability of ZnO is lower than that of ZnSO4, birds fed the 1,500 ppm ZnO treatment excreted significantly more Zn than those fed 1,500 ppm ZnSO4. The Zn levels in breast muscle were not significantly different among the treatments, and there were no other trends in muscle mineral concentration influenced by dietary Zn levels. Sandoval et al. (1998) evaluated the effect of dietary Zn on tissue concentrations in chicks and indicated increasing dietary Zn supplementation resulted in increased Zn concentration in bone, liver, kidney, and muscle. However, they also indicated that the muscle Zn concentration was less sensitive to dietary Zn changes
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
500 (6.53) diets were significantly lower than those in manure from chicks fed the ZnO-1,500 (7.51) diet. However, after 21 d of incubation, there were no significant differences in pH among the treatments.
38
KIM AND PATTERSON
REFERENCES Alumot, E., and R. Bielorai. 1979. Colorimetric determination of uric acid in poultry excreta. J. Assoc. Off. Anal. Chem. 62:1350–1352. Ammerman, C. B., P. R. Henry, and R. D. Miles. 1998. Supplemental organically-bound mineral compounds in livestock
nutrition. Pages 67–91 in Recent Advances in Animal Nutrition. P. C. Garnsworthy and J. Wisemane, ed. Nottingham University Press, Nottingham, UK. AOAC. 1994. Official Methods of Analysis. 16th ed. Association of Official Analytical Chemists. Washington, D.C. Bacharach, U. 1957. The aerobic breakdown of uric acid by certain pseudomonads. J. Gen. Microbiol. 17:1–11. Bongaerts, G. P. A., J. Uitzetter, R. Brouns, and G. D. Vogels. 1978. Uricase of Bacillus fastidiosus properties and regulation of synthesis. Biochim. Biophys. Acta 527:348–358. Caveny, D. D., C. L. Quarles, and G. A. Greathouse. 1981. Atmospheric ammonia and broiler performance and carcass quality. Poult. Sci. 57:1124–1125. Charles, D. R., and C. G. Payne. 1966. The influence of graded levels of atmospheric ammonia on chickens. I. Effects on respiration and on the performance of broilers and replacement growing stock. Br. Poult. Sci. 7:177–187. Deaton, J. W., F. N. Reece, and B. D. Lott. 1984. Effect of atmospheric ammonia on pullets at point of lay. Poult. Sci. 63:384–385. Duncan, D. B. 1955. Multiple range and multiple F-test. Biometrics 11:1–42. Johnson, D., Jr., A. L. Mehring, Jr., F. X. Savino, and H. W. Titus. 1962. The tolerance of growing chickens for dietary zinc. Poult. Sci. 41:311–317. Kim, W. K., and P. H. Patterson. 2003. Effects of minerals on activity of microbial uricase to reduce ammonia volatilization in poultry manure. Poult. Sci. 82:223–231. Moore, P. A., Jr. 1998. Best management practices for poultry manure utilization that enhance agricultural productivity and reduce pollution. Pages 89–117 in Animal Waste Utilization: Effective Use of Manure as a Soil Resource. J. L. Hatfield and B. Stewart, ed. Ann Arbor Press, Chelsea, MI. Nagaraja, K. V., D. A. Emery, K. A. Jordan, V. Sivanandan, J. A. Newman, and B. S. Pomeroy. 1983. Scanning electron microscopic studies of adverse effects of ammonia on tracheal tissues of turkeys. Am. J. Vet. Res. 44:1530–1536. Nagaraja, K. V., D. A. Emery, K. A. Jordan, V. Sivanandan, J. A. Newman, and B. S. Pomeroy. 1984. Effect of ammonia on the quantitative clearance of Escherichia coli from lungs, air sacs, and livers of turkey aerosol vaccinated against Escherichia coli. Am. J. Vet. Res. 45:392–395. Reece, F. N., B. D. Lott, and J. W. Deaton. 1980. Ammonia in the atmosphere during brooding affects performance of broiler chickens. Poult. Sci. 59:486–488. Roberson, R. H., and P. J. Schaible. 1960. The tolerance of growing chicks for high levels of different forms of zinc. Poult. Sci. 39:893–896. SAS. 1994. SAS/STAT User’s Guide: Statistics, Release 6.08. SAS Institute Inc., Cary, NC. Sandoval, M., P. R. Henry, C. B. Ammerman, R. D. Miles, and R. C. Littell. 1997. Relative bioavailability of supplemental inorganic zinc sources for chicks. J. Anim. Sci. 75:3195–3205. Sandoval, M., P. R. Henry, X. G. Luo, R. C. Littell, R. D. Miles, and C. B. Ammerman. 1998. Performance and tissue zinc and metallothionein accumulation in chicks fed a high dietary level of zinc. Poult. Sci. 77:1354–1363. U.S. Environmental Protection Agency (USEPA). 1986. Test Methods for Evaluating Solid Waste. Vol. 1A. 3rd ed. EPA/ SW-846. National Technical Information Service, Springfield, VA.
Downloaded from http://ps.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
than other tissues. They estimated the linear regression of tissue Zn concentrations with dietary Zn concentration. In their model, muscle Zn was found to have a poor fit (r2 = 0.04) compared with the other tissues, such as bone (r2 = 0.99), liver (r2 = 0.79), and kidney (r2 = 0.76). They also showed that dietary Zn supplementation had little effect on the concentrations of other tissue minerals. The Zn supplementation herein significantly reduced the loss of manure total N after the 21-d manure incubation compared with that of chicks fed the control diet. In the present study, however, Zn not only appears to inhibit the activity of microbial uricase but also to reduce the activities of other microbial enzymes related to ammonia production in poultry manure. There are 5 enzymatic steps in aerobic degradation of uric acid (Bacharach, 1957; Bongaerts et al., 1978). First, uricase converts uric acid into allantoin. Second, allantoin is converted into allantoic acid by allantoinase. Third, allantoic acid is converted into ureidoglycolate by allantoate amidohydrolase. Fourth, ureidoglycolate is converted into glyoxylate and urea by ureidoglycolase, and finally, urea is hydrolyzed into ammonia and CO2 by urease. The Zn treatments herein might influence these 5 enzymes, increasing the retention of intermediate components of uric acid. Although there were significant differences in the losses of total N after 21 d of incubation, the total N loss after 21 d of incubation was relatively lower. One of the possible reasons why total N loss was low could have been due to low manure moisture and pH levels. The initial manure samples were not moist, and manure samples quickly dried during the 3-wk incubation. Although the sample manure was collected and frozen daily during the 3-wk feeding trial, the chicks consumed a small amount of feed, producing little manure, and the brooder heating element dried the manure in the collecting trays. Furthermore, the dry manure most likely affected pH level, preventing ammonia N volatilization. The pH of the manure on d 21 in the present study was approximately 6.5, which was much lower than the normal pH of 3-wk-old broiler manure (approximately 9). This low pH in the manure of the present study may have reduced ammonia loss from the manure, diminishing differences in total N among the control and the Zn treatments.