Poult Sci 2008. 87:823-827. doi:10.3382/ps.2007-00101
© 2008 Poultry Science Association
ENVIRONMENT, WELL-BEING, AND BEHAVIOR |
The Effect of Quicklime (CaO) on Litter Condition and Broiler Performance
V. Ruiz*,
D. Ruiz*,
A. G. Gernat*,1,
J. L. Grimes
,
J. G. Murillo*,
M. J. Wineland,
K. E. Anderson and
R. O. Maguire
* Escuela Agricola Panamericana, Zamorano, PO Box 93, Tegucigalpa, Honduras; Department of Poultry Science, North Carolina State University, Raleigh 27695-7608; and Department of Crop and Soil Environmental Science, Virginia Polytechnic Institute and State University, Blacksburg 24061-0002
1 Corresponding author: agernat{at}zamorano.edu
 |
ABSTRACT
|
|---|
High levels of phosphorus and pathogens in runoff are 2 major concerns following manure applications to fields. Phosphorus losses from fields following manure applications have been linked to the solubility of phosphorus in manure; therefore, by decreasing manure phosphorus solubility, a decrease in phosphorus loss in runoff should be apparent. The objective of this research was to develop a process using quicklime that would result in reduced phosphorus solubility and bacteria counts in broiler litter. The 4 litter treatments evaluated were T1, new wood shavings without the addition of quicklime; T2, used, untreated broiler litter; T3, used litter with 10% quicklime (based on the weight of the litter); and T4, used litter with 15% quicklime (based on the weight of the litter). Body weight, cumulative feed consumption, and feed conversion (feed:BW) were determined on a weekly basis through 42 d of age. Mortality was recorded daily. Carcass weights and percentages of carcass yield without giblets were determined prechill. Litter pH, total phosphorus, nitrogen, soluble phosphorus, litter moisture (%), and total plate counts were measured for each litter treatment on d 7 and 42 after bird placement. No significant differences were found for BW, feed consumption, feed conversion, mortality, carcass weight, or carcass yield. No breast or footpad blisters were observed. On d 7, 15% quicklime had higher (P < 0.001) pH (11.2) when compared with the other treatments. Percentages of phosphorus and nitrogen were lower (P < 0.001) for new wood shavings in comparison with the used litter treatments. Soluble phosphorus (ppm) was lower (P < 0.001) for 15% quicklime (2.75) when compared with new wood shavings (42.2), untreated broiler litter (439.2), and 10% quicklime (35.0). Although not significant, 15% quicklime had lower total plate counts (cfu/g) in comparison with the other treatments on d 1 and 10 postmixing and at 7 d after bird placement. Litter conditions on d 42 after bird placement were similar. We concluded that the use of quicklime as a treatment for broiler litter would initially reduce nitrogen and soluble phosphorus and bacteria counts without negatively affecting bird productivity.
Key Words: broiler • litter treatment • quicklime • phosphorus • litter pathogen
|
INTRODUCTION
|
|---|
Changes in state and federal laws in the United States have restricted the amounts and times when poultry manure can be land applied based on N and P standards. Because of these new standards, waste management and disposal are among the most critical issues confronting US confined animal feeding operations. Animal industries today are faced with a number of issues because of continuous growth, increased size, and concentration of operations. For example, land application of poultry manure can pose a threat to ground and surface water quality if applied in areas at risk for storm runoff or if applied above established agronomic rates. The potential presence of pathogens in manure is another concern. The use of lime [CaO and Ca(OH)2] to kill pathogens in biosolids (sewage sludge) is a well-established process. In the United States, the national Environmental Protection Agency Part 503 rule regulates the land application of biosolids and requires treatment to reduce pathogens before land application is permitted (US Environmental Protection Agency, 1999). When lime is the option used for pathogen reduction, the rule requires that sufficient lime is added to raise the pH to 12 for 2 h to kill pathogens (US Environmental Protection Agency, 1999). Another effect that can be observed with the addition of quicklime (QL) and increase of pH in the litter is the liberation of ammonia gas. However, before this type of management practice can be put into widespread use, questions concerning the environmental impact of this type of chemical amendment and its safety in broilers on commercial farms must be addressed (Do et al., 2005). There is an urgent need for innovative methods of collecting, processing, and disposing of manure, mortalities, and by-products such that the environmental impact is minimized. In a study that investigated manures, but not poultry performance, Maguire et al. (2006) showed that liming of broiler litters and layer manures could greatly decrease bacterial counts.
We found no data in the scientific literature on poultry performance and manure condition that directly relate to the use of QL for manure treatment purposes for the poultry industry. Quicklime is a highly reactive product that reacts with water to produce heat and hydrated lime [HL, Ca(OH)2; Budavari, 1996). However, for centuries HL was used widely as a sanitizing agent to control certain bacterial pathogens and parasites, and for the chemical treatment of industrial and municipal sewage before biological treatment was developed. In the 1800s, farmers knew the benefits of using animal manure, soils, and burnt limestone (QL) to enhance crop yields (Langenbeck, 1917; White, 1947). Yushok and Bear (1948) claimed remarkable effects of HL on several poultry pathogens when added to poultry manure. Bennett et al. (2003) evaluated the effect of added HL at the levels of 5, 10, and 20% on survival of Salmonella Enteritidis in used broiler litter and found a significantly reduced Salmonella recovery incidence at 24 h. Incorporating HL at levels of 0.2, 1, and 5% in turkey poult litter resulted in no reduction of Campylobacter or Salmonella recovery, but a reduction in overall aerobic colony-forming units was seen (Bennett et al., 2005). The objective of this study was to develop a process using QL to treat poultry litter so it could be reused as a bedding material and have physical and chemical characteristics acceptable for land application.
|
MATERIALS AND METHODS
|
|---|
Litter Treatment
Before placing birds in the house, wood shavings and used broiler litter were obtained from a local broiler operation (used by 2 previous broiler flocks). Quicklime was obtained from a local quarry outside Tegucigalpa. The 4 treatments were as follows: fresh wood shavings (T1), used broiler litter (T2), used broiler litter mixed with 10% QL (calculated on a weight-per-basis; T3), and used broiler litter mixed with 15% QL (calculated on a weight-per-basis; T4). Percentage moisture was determined (AOAC, 1990) for the used broiler litter before establishing the 4 treatments. Once the percentage moisture was determined, T1 had no water added. Water was added to T2 to reach 30% moisture in the litter. For T3 and T4, water was added to reach a level of 85% moisture. Before adding the water to T3 and T4, the QL was mixed in the litter manually with shovels. The 4 treatments were left in individual piles and turned every other day for 10 d.
Eight subsamples were randomly collected from each litter treatment (pile) and thoroughly mixed to obtain 1 kg of sample for total plate counts (TPC) for aerobic bacteria. For aerobic plate counts, 50 mL of PBS was added to each 10-g sample. Samples were then serially diluted and spread-plated onto tryptic soy agar plates. After spread plating, tryptic soy agar plates were incubated at 37°C for 24 h. Plates were then examined, and total aerobic colony-forming units were enumerated and recorded (Secretaria de Agricultura y Ganadería, 2006). The pH (1:1 litter per water extract), total P (determined by using acid digestion with H2SO4 and H2O2 and analyzed by spectrophotometer), N (Kjeldahl method), soluble P (SP; 1:10 litter per water extract and analyzed by spectrophotometer), and percentage moisture were determined at d 1, and a second collection was repeated at d 10. After completing the 10-d waiting period, the 4 litter treatments were divided and allocated in a randomized complete block design to the 16 experimental pens, giving 4 replicates for each treatment. The litters were provided at a depth of approximately 12.5 cm over concrete flooring.
Bird Placement
One-day-old broiler male chicks were received from a commercial hatchery and placed in an open-sided naturally ventilated broiler house receiving a daily photoperiod of 24 h of light. Each of the 16 pens (2 x 3 m) housed 72 chicks, placed at a density of 12 birds per square meter. Before placing the chicks, the used, untreated and treated litters were top-dressed with approximately 2.5 cm of fresh wood shavings. Each pen was heated by a gas brooder and provided with nipple waterers and tube feeders. Commercial mash diets (Table 1
) and water were provided ad libitum. Body weight, cumulative feed consumption, and feed conversion (feed:BW) were determined by each pen at 7, 14, 21, 28, 35, and 42 d of age. Litter TPC for aerobic bacteria and pH, total P, N, SP, and moisture (%) were measured for each experimental pen when birds were 7 and 42 d of age (following procedures described previously). Mortalities were recorded daily. Birds’ footpads and breasts were observed on a weekly basis for the presence of blisters. Carcass weights and carcass yields (%) without giblets were determined prechill. A second trial was conducted to evaluate the same treatment following the same procedures.
Statistical Analysis
Data from each trial were evaluated by ANOVA with GLM procedures (SAS Institute, 1991). There was no significant trial effect (P > 0.05); therefore, the data from the 2 trials were pooled. Percentage data were subjected to arcsine square root of the percentage transformation, and treatment means were separated by the test of least significant difference. A probability of P 
0 0.05 was required for statements of significance.
|
RESULTS AND DISCUSSION
|
|---|
Litter Condition Postmixing
Treating used litter with QL substantially increased pH on d 1 after mixing for the 10 and 15% addition of QL, and that increase was maintained 10 d postmixing (not statistically analyzed; Tables 2 and 3). A decrease in soluble P was also observed. Maguire et al. (2006) showed that adding at least 10% QL to broiler litter and layer manure decreased soluble P by >90%. Liming has been shown to reduce the solubility of P in biosolids, probably because of the formation of calcium phosphates (Maguire et al., 2001; Penn and Sims, 2002). A similar decrease was also observed for TPC in the same treatments. The mixing of QL with the additional moisture added to the litter caused an exothermic reaction, increasing litter temperature to 65°C and elevating pH (Table 2). Yushok and Bear (1948) reported similar effects of HL on several poultry pathogens when added to poultry manure, although the actual data provided were not sufficient for independent evaluation. Maguire et al. (2006) showed that adding QL to broiler litter and layer manure could decrease bacterial counts by >99%, depending on moisture and QL rate. A decrease in litter moisture was observed from d 1 to 10 and was most probably caused by the heating process occurring in the litter through composting and chemical reaction with QL and additional moisture that was added to the litter. A slight decrease in N content was observed with the treated litters because of the volatilization of ammonia. An increase in total P was also observed, which was probably due to the decreasing moisture level occurring from d 1 to 10 (Tables 2 and 3). Similar decreases that were observed for TPC 1 d after mixing were also observed for TPC in the same treatments 10 d after mixing (Table 3).
Bird Performance
There were no significant differences in BW, feed consumption, feed conversion, mortality, carcass weight, or carcass yield by treatment (Tables 4 and 5), nor were blisters observed on the breasts or footpads (data not shown). Contrary to preliminary early poult performance trials conducted by Bennett et al. (2005), concentrations of lime greater than 5% added to the litter resulted in ocular and respiratory irritation during the first 48 h following placement. However, in his earlier study in 2003, concentrations of 0.2, 1, and 5% lime improved poult performance, apparently associated with the lime treatments. This suggests that the treatment of poultry litter may have beneficial effects on growth during the brooding phase. The inconsistent lime-associated changes in bacterial recovery from the environment in this study would not explain an improvement in poult performance; however, Bennett et al. (2005) suggested it was possible that the lime treatment may have affected a population of opportunistic pathogens not evaluated in the study. In our present study, no ocular or respiratory abnormalities were observed.
Litter Treatment After Bird Placement
The effect of the liming was still evident 7 d after placement (Table 6). Treatment 4 had a significantly (P < 0.001) higher pH (11.12) and percentage moisture (22.2%) when compared with the other treatments (Table 6). Percentages of P and N were significantly (P < 0.001) lower for T1 in comparison with the used litter treatments. This was because the used litter maintained its residual N and P from previous flocks as compared with fresh material that had never been used. Soluble P (ppm) was lower (P < 0.001) for T4 (16.7) when compared with T1 (137.0), T2 (445.2), and T3 (44.0). This was caused by the effect of liming in reducing SP in biosolids (Maguire et al., 2001; Penn and Sims, 2002). Treatment effects on litter condition 42 d after bird placement (Table 7) showed significant differences. Litter pH was higher (P < 0.005) for T3 and T4, with pH of 8.38 and 8.75, respectively. No significant differences were observed for percentage moisture among treatments. Percentage P continued to remain lower (P < 0.01) for T1. Nitrogen content (%) was higher (P < 0.001) for T1 (3.01) than for T2 (2.13), T3 (1.92), and T4 (1.85). Soluble P (ppm) remained lower (P < 0.01) for T4 (35.0) and inclusively for T3 (84.4) when compared with T1 (584.0) and T2 (438.7). No significant differences were found for TPC among treatments (Tables 6 and 7). As expected, the litters had an increase in bacterial counts after the birds were placed.
We demonstrated in this study that the use of CaO as a treatment for broiler litter initially reduced N and soluble P. Placing birds on CaO-treated litter at levels of 10 and 15% (based on the weight of the litter) did not negatively affect bird performance or carcass characteristics. As regulations are developed to reduce P losses from litter-amended soils, the development of processes to reduce the solubility of P will become crucial for the economic survival of intensive poultry production. Our results suggest that lime treatment can successfully decrease P solubility in broiler litter. Overall, the liming process was able to reduce SP in the litter by more than 90%, which should greatly reduce concerns about P losses in runoff following land application of these materials.
Received for publication February 28, 2007.
Accepted for publication February 14, 2008.
|
REFERENCES
|
|---|
AOAC. 1990. Official Methods of Analysis. 15th ed. Assoc. Off. Anal. Chem., Alexandria, VA.Bennett, D. D., S. E. Higgins, R. W. Moore, R. Beltran, D. J. Caldwell, J. A. Byrd II, and B. M. Hargis. 2003. Effects of lime on Salmonella enteritidis in vitro. J. Appl. Poult. Res. 12:65–68.[Abstract/Free Full Text]
Bennett, D. D., S. E. Higgins, R. W. Moore, J. A. Byrd II, R. Beltran, C. Corsiglia, D. J. Caldwell, and B. M. Hargis. 2005. Effects of addition of hydrated lime to litter on recovery of selected bacteria and poult performance. J. Appl. Poult. Res. 14:721–727.[Abstract/Free Full Text]
Budavari, S. 1996. Page 1735 in the Merck Index. 12th ed. Merck and Co. Inc., Whitehouse Station, NJ.
Do, J. C., I. H. Choi, and K. H. Nahm. 2005. Effects of chemically amended litter on broiler performance, atmospheric ammonia concentration, and phosphorus solubility in litter. Poult. Sci. 84:679–686.[Abstract/Free Full Text]
Langenbeck, K. 1917. The practical advantage of burned lime over ground limestone. The Agricultural Lime Bureau, Washington, DC.
Maguire, R. O., D. Hesterberg, A. G. Gernat, K. Anderson, M. Wineland, and J. Grimes. 2006. Liming poultry manures to decrease soluble phosphorus and suppress the bacteria population. J. Environ. Qual. 35:849–857.[Abstract/Free Full Text]
Maguire, R. O., J. T. Sims, S. K. Dentel, F. J. Coale, and J. T. Mah. 2001. Relationship between biosolids treatment process and soil phosphorus availability. J. Environ. Qual. 30:1023–1033.[Abstract/Free Full Text]
Penn, C. J., and J. T. Sims. 2002. Phosphorus forms in biosolids-amended soils and losses in runoff: Effects of wastewater treatment process. J. Environ. Qual. 31:1349–1361.[Abstract/Free Full Text]
SAS Institute. 1991. SAS User’s Guide: Statistics. Version 5 ed. SAS Inst. Inc., Cary, NC.
Secretaria de Agricultura y Ganadería. 2006. Secretaria de Agricultura y Ganadería, Dirección de Ciencia y Tecnología, Colonia Lomas Linda Norte, Tegucigalpa, Honduras.
US Environmental Protection Agency. 1999. Biosolids generation, use, and disposal in the United States. US EPA, Office of Wastewater Management, Washington, DC.
White, J. W. 1947. The use of burned lime products in soil improvement. Pit Quarry (May).
Yushok, W., and F. E. Bear. 1948. Poultry manure: Its preservation, deodorization, and disinfection. N. J. Agric. Exp. Stn. Bull. 707:3–11.
TOP
ABSTRACT
INTRODUCTION
