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ANIMAL NUTRITION |
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-1151
| Abstract |
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Key Words: Meat and Bone Meal Metabolizable Energy Pig Regression Slope
| Introduction |
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Using 14 samples of MBM from rendering plants in Australia, Batterham et al. (1980)
reported DE values between 2,393 and 3,585 kcal/kg of DM in growing pigs; however, ME content of these samples was not determined. In another study, Shi and Noblet (1993)
reported ME of 2,175 and 3,011 kcal/kg of DM for growing pigs and sows. These are the only reports found in the literature that specifically determined the energy values of MBM for pigs. The importance of accurate and reliable ME values for MBM becomes evident when one considers the fact that energy is the most expensive component of swine diets. Thus, the objective of this study was to determine the ME and MEn in 12 samples of MBM for pigs, and to develop regression equations that described the variation in ME or MEn of MBM in relation to chemical composition.
| Materials and Methods |
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Twelve samples of MBM were selected to provide a wide range of chemical composition (Table 1
) and were used in these experiments to determine the ME and MEn for pigs. All samples were cooked in a Dupps Continuous Cooker at 129 to 135°C except Sample 11, which was cooked at 132 to 138°C. Sample 1 was derived from all-beef packer slaughter material. Sample 2 was derived from a high percentage of beef packer slaughter material, with a small component of extra offal and swine raw material. Sample 3 was derived from 30% bovine whole carcasses and 65% swine whole carcasses, with a small component of meat processing trimmings of multiple species. Sample 4 was derived primarily from whole cattle carcasses, with small amounts of mixed-species processing trim and beef packer slaughter material. Sample 5 was composed of mixed-species raw material derived from processing trim and bone. Sample 6 was composed of mixed-species raw material derived from pork slaughter, beef packer slaughter, and beef processing trim and bone of approximately 70% beef and 30% pork plus a small quantity of poultry processing and whole bird carcasses. Sample 7 was derived from all slaughter and processing material, with no whole carcasses included, mixed raw material of both beef and pork slaughter and processing, with near equal quantities from both species. Sample 8 was packer-derived material from exclusive swine slaughter. Sample 9 was derived from 80% beef slaughter and processing, 10% whole beef and swine carcasses of near equal weight proportions, and small amount of poultry heads, necks, and discards. Sample 10 was derived from raw material composed of 60% beef packer material, 25% poultry backs and necks, and 15% grocery store trimmings, and outdated muscle meats and processed meats. Sample 11 was derived from beef and pork slaughter material of approximately equal proportions, with up to 10% turkey slaughter and processing tissue comprising a greater bone content. There was no whole carcass material from either beef or swine. Sample 12 was derived from nearly exclusive all pork from a packer processing sows for sausage.
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Given that ME values are extremely difficult to determine directly using MBM as the sole source of dietary energy, each of the 12 MBM samples were used in diets formulated with 0, 50, or 100 g of MBM substitution of corn and soybean meal (SBM) in a basal 170 g CP/kg (as-fed basis) corn-SBM diet. Corn and SBM were adjusted to constant ratio (1.8:5.5 for the 50 g MBM/kg diet, and 3.6:11 for the 100 g MBM/kg diet) in the substitutions. Because all the energy in the basal diet was derived from corn and SBM, this constant ratio was key for the algebraic equations (described below) used in the indirect method of ME determination to derive the contribution of MBM to energy intake. To minimize the negative effect of the use of N-containing compounds for energy, the three diets for each MBM sample were formulated to have comparable CP content (Table 2
). The same batches of corn and SBM were used for formulating all diets, so the only source of variation was the 12 samples of MBM.
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The Purdue University Animal Care and Use Committee approved all animal care procedures. Two hundred and eighty-eight Yorkshire-Landrace barrows, with an average BW of 35 ± 3.1 kg, were used in this study. The basal diet was corn-SBM based with 0 g MBM per kilogram diet (Diet 1; Table 2
). For each MBM source, each of the three diets containing 0, 50, or 100 g of MBM/kg diet (Diets 1, 2, or 3; Table 2
) was fed to eight barrows in a metabolism assay that used a 5-d adjustment period, followed by a 5-d period of total, but separate, collection of feces and urine. Pigs were housed in stainless-steel metabolism crates (1.85 m x 0.70 m), equipped with stainless steel feeders and low pressure water nipples that allowed separate collection of feces and urine using protocols described by Adeola and Bajjalieh (1997)
. The 5-d adjustment period allowed the barrows to adjust to their new environment and attain an intake of approximately 5% of their BW at the beginning of the collection. They were fed equal quantities of diets twice daily (0700 and 1700). This quantity was adjusted until each pig was able to consume all the feed that was given. On the morning of d 6, fecal trays and urine collection vessels containing 10% formalin were placed under the metabolism crates to initiate collection of urine for 5 d. For fecal collection, 2 g of ferric oxide was fed in 100 g of assigned diet at the time of placement of the sample collection trays and screens. Feeding of the remaining portion of morning feed was after the ingestion of the 100 g of assigned diet and marker. The appearance of the marker in the feces signaled the beginning of fecal collection. On the morning of d 11, urine collection was terminated, and 2 g of ferric oxide was again fed in 100 g of assigned diet, with the remaining feed provided as described for the study initiation. On appearance of the marker in the feces, fecal collection was terminated. Feces were collected once daily, weighed, and stored at 4°C. Urine was collected at the time of feces collection, measured in a graduated cylinder, and a 35% aliquot of urine was collected and frozen.
Chemical Analyses
All MBM samples were analyzed for CP (N x 6.25), AA, crude fat (CF), Ca, and P at the University of Missouri Experiment Station Chemical Laboratory. Nitrogen content of the MBM samples was determined by the combustion method (990.03; AOAC, 2000
). Amino acids were determined by HPLC (982.30 E [a, b, c]; AOAC, 2000
). Crude fat was determined by the ether extraction method (934.01; AOAC, 2000
). Meat and bone meal samples were digested by the nitric and perchloric acid wet digestion method (935.13A; AOAC, 2000
). Calcium and P were determined by inductively coupled plasma atomic emission spectroscopy (990.08; AOAC, 2000
).
The frozen feces were thawed (the entire collection for each pig was pooled), placed in an aluminum pan, weighed, and dried at 55°C. The dried feces, MBM samples, and diets were ground to pass a 0.5-mm screen to facilitate analysis, after which these samples were thoroughly mixed and sampled. Dry matter content of the feces, MBM samples, and diets was determined by drying the samples at 100°C for 24 h. The GE content of feces, MBM samples, and diets was determined by adiabatic bomb calorimetry (Model 1261; Parr Instrument Co., Moline, IL), with benzoic acid as a standard. Nitrogen content of feces and diets was determined by the combustion method (990.03; AOAC, 2000
) using a Leco Model FP-2000 N analyzer (Leco Corp., St. Joseph, MI), with EDTA as a standard. The ash content of the MBM samples was determined by drying the sample overnight at 100°C, followed by ashing in a muffle furnace for 18 h at 600°C.
The urine collected was thawed, thoroughly mixed and sampled, and filtered through glass wool. Known volumes (between 300 and 800 mL, depending on the total volume produced) of duplicate urine samples were measured into aluminum pans and weighed. Urine was dried at 55°C, weighed, and stored in Whirl-Pak (Nasco, Fort Atkinson, WI) bags at 18°C. The dried urine samples were then analyzed for GE and N as described for fecal samples. Duplicate analyses were performed on all diets, feces, MBM samples, orts, and urine samples.
Calculations
The ME content of the diet was calculated as the difference between energy in the dietary intake and the sum of energy in the orts, feces, and urine. Metabolizable energy in Diet 1 (the basal diet, ME1) was contributed by 0.715 corn and 0.235 soybean meal (SBM). Thus:
![]() | [Eq. 1] |
Using the ME contents of corn and SBM at 3,420 and 3,385 kcal/kg (NRC, 1998
), respectively, and their ratios:
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The ME in Diet 2 (the diet containing 50 g MBM/kg diet, ME2) was contributed by 0.733 corn, 0.180 SBM, and 0.05 MBM. Thus:
![]() | [Eq. 2] |
The ME in Diet 3 (the diet containing 100 g of MBM/kg diet, ME3) was contributed by 0.750 corn, 0.125 SBM, and 0.10 MBM. Thus:
![]() | [Eq. 3] |
Using the ME contents of corn and SBM at 3,420 and 3,385 kcal/kg (NRC, 1998
), respectively, and their ratios, and substituting corn and SBM in the equations above gives:
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Rearranging the above gives:
![]() | [Eq. 4] |
for the contribution (kcal/kg) of MBM to ME of Diet 2
![]() | [Eq. 5] |
for the contribution (kcal/kg) of MBM to ME of Diet 3.
The products of Eq. 4 or 5 and the quantities (in kilograms) of MBM intake by pigs fed Diet 2 or 3, respectively, represent MBM contributions to ME intake (kcal) in pigs fed those respective diets (Diet 2 or 3). As indicated in the diet formulation section above, substitution of the constant ratio of corn and SBM with MBM formed the basis for Eq. 1 to 5. The ME corrected for retained N (MEn) was calculated using a caloric value of 7.45 kcal/g of N (Harris et al., 1972
).
Statistical Analyses
The data for each MBM sample were analyzed as a randomized complete block design of three diets in eight blocks, using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC). Orthogonal polynomial contrasts (linear and quadratic) were used to compare the treatment means. Meat and bone meal contribution to ME or MEn intake in kilocalories was regressed against kilograms of MBM intake for each pig on each MBM sample using the GLM procedure of SAS, with block as a source of variation and the solutions option. The slope of the regression gave the ME or MEn content of the MBM sample. Pearson correlations were generated using the CORR procedure of SAS, and multiple linear regression (PROC STEPWISE) analyses were carried out by regressing the ME or MEn of MBM on the analyzed chemical constituents of the MBM samples.
| Results |
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| Discussion |
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The chemical composition of the MBM samples used in this study is similar to values reported by Young et al. (1977)
, Batterham et al. (1980)
, and Sibbald et al. (1980)
. Furthermore, Shi and Noblet (1993)
, Wang and Parsons (1998)
, and Ravindran et al. (2002)
reported chemical compositions of MBM that were similar to our samples. In contrast, Sartorelli et al. (2003)
reported relatively lower values for CP and GE but relatively higher values for percentage of ash, P, and Ca than the MBM used in the current studies. The MBM samples in Sartorelli et al. (2003)
had a lower Ca:P ratio (1.59 to 2.13) than found in the MBM we used (Ca:P ratio from 2.12 to 2.42). According to the definition of Scott and Dean (1991)
, four of our MBM samples would not be MBM due to the P concentration being lower than 4%. As percentage of ash increased, GE decreased, which agrees with the observations of Wang and Parsons (1998)
.
The variability in chemical composition of these MBM samples may be due to the effects of location, processing methods (Wang and Parsons, 1998
), and/or the source of the MBM (Kirstein, 1999
), which would influence its digestibility for nonruminants (Parsons et al., 1997
; Wang and Parsons, 1998
; Kirstein, 1999
). The MBM samples in this study were selected to maximize variability. The variation in individual chemical components of MBM alone accounted for only a small and insignificant proportion of the variability in the ME or MEn.
The energy needs of nonruminants form the cornerstone of diet formulation (Ewan, 2001
). Metabolizable energy is used for maintenance, growth, and production. Excess AA are deaminated, with the N excreted and the carbon skeleton metabolized in cells to generate energy; however, this process consumes energy. In the current study, CP concentrations were identical, so energy use would be an accurate comparison. Energy use in this study, irrespective of the level of MBM substitution, was approximately 83% (data not shown). The only notable exceptions were MBM Samples 2 and 6, in which there was a linear decrease in energy digestibility. These values fall within the range reported by Shi and Noblet (1993)
. The dietary MEn showed that most of the pigs retained N. This is an indication that the energy supplied by the MBM is as well utilized as that in the basal diet (based on corn and SBM).
The variation in the ME and MEn values of the MBM is important when determining the quantity of MBM to be included in the diet. The ME and MEn values in this study were similar to those reported by Shi and Noblet (1993)
for growing pigs (2,175 kcal/kg). Batterham et al. (1980)
reported that the best relationship between DE of MBM and the chemical constituents of the MBM resulted from a combination of GE, CF, Ca, and P, and the use of GE or CP and CF also gave reliable values. They also observed, however, that the difference in MBM digestibility could not be accounted for solely by the variation in the chemical constituents of the MBM. Due to greater GE and lower ash, it would be expected that MBM Sample 2 would give a greater ME and MEn than Sample 1; however, the opposite was the case in this study. One explanation for the low ME value of Sample 2 could be the poor quality of the MBM sample, as pigs on diets containing this particular MBM had significantly lower DE and energy digestibility resulting in low ME and MEn of the diets. The contribution of Sample 2 to diet ME was relatively small compared with the other MBM samples. Pigs on 8 of the 12 MBM samples retained N, as reflected by the lower MEn values.
A number of factors may be responsible for the insignificant correlation between ME or MEn and chemical components of the MBM samples. The level of fiber in the MBM samples, which may be up to 2% (Shi and Noblet, 1993
), and the proportion of the ratio of saturated to unsaturated fatty acids may play an important role, especially as it affects fat absorption (Atteh and Leeson, 1984
; Leeson and Summers, 2001
). Unsaturated fats have more rancidity problems affecting consumption and use.
The results presented in this study indicate the individuality of GE, CP, and CF of the MBM are not proportional to the ME or MEn of the MBM. Interactions of these components of the MBM, along with other factors such as quality of the MBM, determine the energy in MBM that is metabolized by pigs.
| Footnotes |
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2 Correspondence: 915 W. State St. (phone: 765-494-4848; fax: 765-494-9346; e-mail: ladeola{at}purdue.edu).
Received for publication November 10, 2004. Accepted for publication July 20, 2005.
| Literature Cited |
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This article has been cited by other articles:
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O. A. Olukosi and O. Adeola Estimation of the metabolizable energy content of meat and bone meal for swine J Anim Sci, August 1, 2009; 87(8): 2590 - 2599. [Abstract] [Full Text] [PDF] |
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S. A. Adedokun, C. M. Parsons, M. S. Lilburn, O. Adeola, and T. J. Applegate Standardized Ileal Amino Acid Digestibility of Meat and Bone Meal from Different Sources in Broiler Chicks and Turkey Poults with a Nitrogen-Free or Casein Diet Poult. Sci., December 1, 2007; 86(12): 2598 - 2607. [Abstract] [Full Text] [PDF] |
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