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Calculation of the Moisture and Protein Content of Market Chickens from the Fat Content
152
E. H. MCNALLY
During the last 120 days of the second experiment the maximum temperature was 100 degrees F. or higher on 90 days and 110 degrees F. or higher on five days, with the highest temperature of 112 degrees F. SUMMARY
REFERENCES Heywang, B. W., 1947. Diets for laying chickens during hot weather. The protein level of the diet. Poultry Sci. 27:38-43. National Research Council, Washington 25, D. C , June 1944 (rev. 1950). Recommended nutrient allowances for domestic animals. No. 1, Recommended nutrient allowances for poultry.
Calculation of the Moisture and Protein Content of Market Chickens from the Fat Content E. H. MCNALLY U. S. Department of Agriculture, Agricultural Research Service, Animal and Poultry Husbandry Research Branch, Beltsville, Maryland (Received for publication May 7, 1954)
S
EVERAL attempts have been made to develop indirect methods for determining the crude chemical composition, the moisture, protein, fat and ash, of meat animals. The composition of beef, pork and mutton carcasses and parts may be calculated with fair accuracy when the fat content is known since the moisture and protein content of the carcass is fairly constant when calculated on a fat-free basis (Moulton et al., 1922). A further im-
provement in the method of calculations was made by Callow (1935) by use of linear regression equations based on the fat content, since the equations will adjust for a residual fat which is present even in lean animals. The crude chemical composition of market poultry has been studied in relation to growth and nutrition by Mitchell, Card and Hamilton (1926), Harshaw (1938), and others. Further information
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
In one experiment conducted during 112 days of hot weather, and in another conducted during 120 days of hot and 153 days of relatively cool and moderate weather, laying White Leghorn pullets were fed diets containing varying quantities of sardine meal and casein to bring their total protein content to about 11.5, 13.0, 15.0, 16.5, 18.0, and 19.3 percent. The total protein content of the diet fed to three groups in the second experiment was different during hot weather than during cool and moderate weather. Average total egg production per pullet in the first experiment was less when the protein content of the diet was 11.5 percent than when it was 13.0 percent, but not greater when it was more than 13.0 percent. The results in the second experi-
ment, both in the groups fed the same diets throughout the experiment and in the groups where the protein level of the diet was changed, indicate that the optimum level of protein was 15.0 percent during both hot weather and relatively cool and moderate weather. Considered collectively, the data from both experiments thus indicate that no increase in egg production would occur if the protein level in the diet of laying chickens were greater than 15.0 percent during hot weather. Differences among group averages of maintenance of weight by the pullets during hot weather were small in most instances, and are not considered appreciable.
CARCASS MOISTURE AND PROTEIN CONTENT IN RELATION TO FAT
In preliminary calculations, the composition was computed from the averages calculated on a fat-free basis. Further study showed that calculations based upon regression lines gave a much better approximation of the chemical values. When the fat content was plotted in rela-
TABLE 1.—Regression equations for calculation of protein, moisture and ash from the fat content of poultry meat (Percentage) Corr. coeff. r
Regression equation Ey=a+bx
%
Breast muscle Moisture-Fat Protein-Fat Ash-Fat Leg muscle Moisture-Fat Protein-Fat Ash-Fat Remainder edible Moisture-Fat Protein-Fat Ash-Fat Total edible Moisture-Fat Protein-Fat Ash-Fat
Standard error of estimate
.99 .50 .73
Ey = U.6 -0.4939* 24.32-0.5568* 1.41-0.0299*
+ 1.15 ±1.64 ±0.05
.99 .57 .49
Ey = 7S. 58-1.200* 21.78-0.3500* 1.13-0.0186*
+ 0.83 + 0.74 ±0.04
.96 .66
—
fiy = 75.15-0.7255* 22.74-0.2340* 2.55-0.0816*
±0.91 ±0.92 ±0.04
.99 .92 .47
£y = 75.99-0.7615* 22.02-0.2212* 1.24-0.0197*
±0.54 ±0.69 ±0.08
tion to moisture, protein, and ash, a straight line relation was observed for the breast and leg muscles, the remainder and the total edible meat (see Figure 1). The fattened and unfattened cockerels and hens were all on the same regression line, so that a single regression line could be calculated which would cover the composition during growth and fattening of both sexes. The calculated regression equations and their standard error of estimates are given in Table 1. The correlation coefficients are of slight value in this case since they are based upon parts of the whole, and such a component as moisture, which is about 75 percent of the whole, gives an abnormally high correlation. The correlation coefficients do however show the high correlations found and how large they should be to have value for calculations from regression equations. The standard error of estimate may be used to evaluate the precision of the calculations made from the regression equations. From the standard errors as calculated, it is apparent that the regression equations may be used to calculate the moisture and protein content of the total edible meat and the leg muscle. The ash content of the various analyzed parts is so small that it cannot be calculated with precision. The
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
would be useful as to the relationships between the various crude chemical components. For example, it is often stated that fat displaced the moisture on fattening and finishing of market poultry. The object of this study was to determine if similar relationships were to be found in poultry between the fat, moisture, protein, and ash content as have been found in mammals. If such interrelationships were found, which method of calculation would give the best accuracy, and are these methods of calculation suitable for all chemical components and carcass parts? With meat animals the effect of growth, fattening and sex should also be considered in relation to the chemical composition. The individual weights and crude chemical composition of the parts of 80 Rhode Island Red cockerels at various ages (8 to 22 weeks) were available in this laboratory and had been previously reported by Harshaw (1938). One-half of the cockerels were fattened so both growth and fattening could be included in relation to the chemical composition of the cockerels. Two groups of Rhode Island Red hens of 10 each, fattened and unfattened, were also included so that sex differences, if present, would be observed. The birds were all killed, dressed and eviscerated under as uniform conditions as possible. The leg and breast muscles were dissected from the eviscerated carcass and then all other edible meat and scraps were placed together as the remainder. The composition of total edible meat was calculated from the composition of the parts.
153
154
E. H. MCNALLY
FIG. 1. Relation between fat content and moisture and protein in total edible meat from eviscerated poultry (Percentage).
fat content of the breast muscle is also so small and the range so limited that the use of regression equations is not worth while. A comparison of the values of the chemical components as calculated from the regression equations and those chemically
determined are given in Table 2 for the total edible meat. Even in the chemically determined values some errors due to sampling and the lack of precision of the method used are involved. The precision of calculation from the regression equation for the total edible meat would seem to make their use of value.
SUMMARY TABLE 2.—Calculated composition of total edible meat of poultry from fat content regression The crude chemical components, fat, equations {Percentage) Moisture Fat Chemi- ChemiCalcucal cal lated
%
4.81 10.96 2.20 12.34 2.94 8.84 2.07 16.51 20.41 13.84 Average
%
72.08 69.25 74.26 67.46 73.43 69.07 74.20 63.92 61.36 64.85 68.988
„
%
72.33 66.88 74.31 66.59 73.75 69.26 74.41 63.42 60.45 65.45 68.685
Protein Chemical
%
23.83 18.76 21.91 19.04 21.97 20.59 22.52 18.30 20.41 20.06 20.739
Ash
Calculated
%
20.96 19.60 21.54 19.29 21.37 20.06 21.56 18.37 17.51 19.96 19.922
Chemi- Calcucal lated
%
1.16 .90 1.16 .94 1.05 1.01 1.05 .89 .83 .75 .983
%
1.14 1.03 1.20 1.02 1.18 1.07 1.20 .91 .84 .97 1.065
protein, moisture, and ash of poultry meat show an interrelation of values. The moisture and protein content of poultry meat on a fat-free basis is fairly constant. Linear regression lines may be calculated for the relation of the fat content to the moisture, protein and ash content of poultry meat. The fat as a component of the tissue re-
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
PERCENT FAT
PROTEIN INTAKE AND WATER METABOLISM
try may be calculated from the regression equations of the fat content. REFERENCES Callow, E. H., 1935. Carcass quality of the pig in relation to growth and diet. Empir. J. Exp. Agr. 3:80. Harshaw, H. M., 1938. The effect of fattening at different ages on the composition of cockerels. Poultry Sci. 17: 163-169. Mitchell, H. H., L. E. Card and T. S. Hamilton, 1926. The growth of White Plymouth Rock chickens. Illinois Agr. Exp. Sta. Bull. 278. Moulton, C , P. F. Trowbridge and L. D. Haigh, 1922. Studies in animal nutrition. Missouri Agr. Exp. Sta. Res. Bull. 54.
Influence of Protein Source on Consumption and Excretion of Water and Excreta Voided by Broiler Chicks H.
PATRICE
Pottltry Department, University of Tennessee, Knoxmlle (Received for publication May 11, 1954)
T
HE accumulation of water in poultry house litter is a much discussed problem. Charles et al. (1942) reviewed the problem of moisture in poultry house litter and concluded that poultry droppings, respiration, water spillage by birds and attendants, atmospheric moisture, and snow or rain blown into the pens were the most important factors involved in wet litter. James and Wheeler (1949) and Wheeler and James (1949, 1950) reported that the amount of water consumed and excreta voided varied almost directly with the protein level of the diet. They also reported that although the amount of water consumed was greater when the protein intake was increased, the percentage of moisture remained relatively constant in the droppings—approximately 71 percent. Glista and Scott (1949) found that the gross water consumption increased
with soybean oil meal intake. Eley and Hoffman (1949) obtained no relationship between feed particle size, moisture content of droppings, water or feed consumption, or weight gains. Reported in this manuscript are data showing the influence of adding different protein concentrates to broiler rations on consumption and excretion of water and excreta voided by broiler chicks. EXPERIMENTAL
Broiler strain chicks were used during these studies. They were fed a regular broiler ration containing 21 percent protein until 5 weeks of age, then placed on the supplemented rations outlined in Tables 1 and 2. The supplemented rations were composed of the regular ration to which different protein concentrates had been added by replacing the corn meal to bring the protein level up to 27 percent.
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
duces the moisture and protein content in proportion to their quantity in the fat-free material. Growth, fattening and sex do not affect the crude chemical composition as calculated on a fat-free basis, or from regression lines calculated from the fat content. The crude chemical composition of the breast muscle and the ash content of the total edible meat and leg muscle cannot be calculated from the regression equations with more than fair accuracy. The crude chemical composition of the total edible meat and leg muscle of poul-
155
E. H. MCNALLY
During the last 120 days of the second experiment the maximum temperature was 100 degrees F. or higher on 90 days and 110 degrees F. or higher on five days, with the highest temperature of 112 degrees F. SUMMARY
REFERENCES Heywang, B. W., 1947. Diets for laying chickens during hot weather. The protein level of the diet. Poultry Sci. 27:38-43. National Research Council, Washington 25, D. C , June 1944 (rev. 1950). Recommended nutrient allowances for domestic animals. No. 1, Recommended nutrient allowances for poultry.
Calculation of the Moisture and Protein Content of Market Chickens from the Fat Content E. H. MCNALLY U. S. Department of Agriculture, Agricultural Research Service, Animal and Poultry Husbandry Research Branch, Beltsville, Maryland (Received for publication May 7, 1954)
S
EVERAL attempts have been made to develop indirect methods for determining the crude chemical composition, the moisture, protein, fat and ash, of meat animals. The composition of beef, pork and mutton carcasses and parts may be calculated with fair accuracy when the fat content is known since the moisture and protein content of the carcass is fairly constant when calculated on a fat-free basis (Moulton et al., 1922). A further im-
provement in the method of calculations was made by Callow (1935) by use of linear regression equations based on the fat content, since the equations will adjust for a residual fat which is present even in lean animals. The crude chemical composition of market poultry has been studied in relation to growth and nutrition by Mitchell, Card and Hamilton (1926), Harshaw (1938), and others. Further information
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
In one experiment conducted during 112 days of hot weather, and in another conducted during 120 days of hot and 153 days of relatively cool and moderate weather, laying White Leghorn pullets were fed diets containing varying quantities of sardine meal and casein to bring their total protein content to about 11.5, 13.0, 15.0, 16.5, 18.0, and 19.3 percent. The total protein content of the diet fed to three groups in the second experiment was different during hot weather than during cool and moderate weather. Average total egg production per pullet in the first experiment was less when the protein content of the diet was 11.5 percent than when it was 13.0 percent, but not greater when it was more than 13.0 percent. The results in the second experi-
ment, both in the groups fed the same diets throughout the experiment and in the groups where the protein level of the diet was changed, indicate that the optimum level of protein was 15.0 percent during both hot weather and relatively cool and moderate weather. Considered collectively, the data from both experiments thus indicate that no increase in egg production would occur if the protein level in the diet of laying chickens were greater than 15.0 percent during hot weather. Differences among group averages of maintenance of weight by the pullets during hot weather were small in most instances, and are not considered appreciable.
CARCASS MOISTURE AND PROTEIN CONTENT IN RELATION TO FAT
In preliminary calculations, the composition was computed from the averages calculated on a fat-free basis. Further study showed that calculations based upon regression lines gave a much better approximation of the chemical values. When the fat content was plotted in rela-
TABLE 1.—Regression equations for calculation of protein, moisture and ash from the fat content of poultry meat (Percentage) Corr. coeff. r
Regression equation Ey=a+bx
%
Breast muscle Moisture-Fat Protein-Fat Ash-Fat Leg muscle Moisture-Fat Protein-Fat Ash-Fat Remainder edible Moisture-Fat Protein-Fat Ash-Fat Total edible Moisture-Fat Protein-Fat Ash-Fat
Standard error of estimate
.99 .50 .73
Ey = U.6 -0.4939* 24.32-0.5568* 1.41-0.0299*
+ 1.15 ±1.64 ±0.05
.99 .57 .49
Ey = 7S. 58-1.200* 21.78-0.3500* 1.13-0.0186*
+ 0.83 + 0.74 ±0.04
.96 .66
—
fiy = 75.15-0.7255* 22.74-0.2340* 2.55-0.0816*
±0.91 ±0.92 ±0.04
.99 .92 .47
£y = 75.99-0.7615* 22.02-0.2212* 1.24-0.0197*
±0.54 ±0.69 ±0.08
tion to moisture, protein, and ash, a straight line relation was observed for the breast and leg muscles, the remainder and the total edible meat (see Figure 1). The fattened and unfattened cockerels and hens were all on the same regression line, so that a single regression line could be calculated which would cover the composition during growth and fattening of both sexes. The calculated regression equations and their standard error of estimates are given in Table 1. The correlation coefficients are of slight value in this case since they are based upon parts of the whole, and such a component as moisture, which is about 75 percent of the whole, gives an abnormally high correlation. The correlation coefficients do however show the high correlations found and how large they should be to have value for calculations from regression equations. The standard error of estimate may be used to evaluate the precision of the calculations made from the regression equations. From the standard errors as calculated, it is apparent that the regression equations may be used to calculate the moisture and protein content of the total edible meat and the leg muscle. The ash content of the various analyzed parts is so small that it cannot be calculated with precision. The
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
would be useful as to the relationships between the various crude chemical components. For example, it is often stated that fat displaced the moisture on fattening and finishing of market poultry. The object of this study was to determine if similar relationships were to be found in poultry between the fat, moisture, protein, and ash content as have been found in mammals. If such interrelationships were found, which method of calculation would give the best accuracy, and are these methods of calculation suitable for all chemical components and carcass parts? With meat animals the effect of growth, fattening and sex should also be considered in relation to the chemical composition. The individual weights and crude chemical composition of the parts of 80 Rhode Island Red cockerels at various ages (8 to 22 weeks) were available in this laboratory and had been previously reported by Harshaw (1938). One-half of the cockerels were fattened so both growth and fattening could be included in relation to the chemical composition of the cockerels. Two groups of Rhode Island Red hens of 10 each, fattened and unfattened, were also included so that sex differences, if present, would be observed. The birds were all killed, dressed and eviscerated under as uniform conditions as possible. The leg and breast muscles were dissected from the eviscerated carcass and then all other edible meat and scraps were placed together as the remainder. The composition of total edible meat was calculated from the composition of the parts.
153
154
E. H. MCNALLY
FIG. 1. Relation between fat content and moisture and protein in total edible meat from eviscerated poultry (Percentage).
fat content of the breast muscle is also so small and the range so limited that the use of regression equations is not worth while. A comparison of the values of the chemical components as calculated from the regression equations and those chemically
determined are given in Table 2 for the total edible meat. Even in the chemically determined values some errors due to sampling and the lack of precision of the method used are involved. The precision of calculation from the regression equation for the total edible meat would seem to make their use of value.
SUMMARY TABLE 2.—Calculated composition of total edible meat of poultry from fat content regression The crude chemical components, fat, equations {Percentage) Moisture Fat Chemi- ChemiCalcucal cal lated
%
4.81 10.96 2.20 12.34 2.94 8.84 2.07 16.51 20.41 13.84 Average
%
72.08 69.25 74.26 67.46 73.43 69.07 74.20 63.92 61.36 64.85 68.988
„
%
72.33 66.88 74.31 66.59 73.75 69.26 74.41 63.42 60.45 65.45 68.685
Protein Chemical
%
23.83 18.76 21.91 19.04 21.97 20.59 22.52 18.30 20.41 20.06 20.739
Ash
Calculated
%
20.96 19.60 21.54 19.29 21.37 20.06 21.56 18.37 17.51 19.96 19.922
Chemi- Calcucal lated
%
1.16 .90 1.16 .94 1.05 1.01 1.05 .89 .83 .75 .983
%
1.14 1.03 1.20 1.02 1.18 1.07 1.20 .91 .84 .97 1.065
protein, moisture, and ash of poultry meat show an interrelation of values. The moisture and protein content of poultry meat on a fat-free basis is fairly constant. Linear regression lines may be calculated for the relation of the fat content to the moisture, protein and ash content of poultry meat. The fat as a component of the tissue re-
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
PERCENT FAT
PROTEIN INTAKE AND WATER METABOLISM
try may be calculated from the regression equations of the fat content. REFERENCES Callow, E. H., 1935. Carcass quality of the pig in relation to growth and diet. Empir. J. Exp. Agr. 3:80. Harshaw, H. M., 1938. The effect of fattening at different ages on the composition of cockerels. Poultry Sci. 17: 163-169. Mitchell, H. H., L. E. Card and T. S. Hamilton, 1926. The growth of White Plymouth Rock chickens. Illinois Agr. Exp. Sta. Bull. 278. Moulton, C , P. F. Trowbridge and L. D. Haigh, 1922. Studies in animal nutrition. Missouri Agr. Exp. Sta. Res. Bull. 54.
Influence of Protein Source on Consumption and Excretion of Water and Excreta Voided by Broiler Chicks H.
PATRICE
Pottltry Department, University of Tennessee, Knoxmlle (Received for publication May 11, 1954)
T
HE accumulation of water in poultry house litter is a much discussed problem. Charles et al. (1942) reviewed the problem of moisture in poultry house litter and concluded that poultry droppings, respiration, water spillage by birds and attendants, atmospheric moisture, and snow or rain blown into the pens were the most important factors involved in wet litter. James and Wheeler (1949) and Wheeler and James (1949, 1950) reported that the amount of water consumed and excreta voided varied almost directly with the protein level of the diet. They also reported that although the amount of water consumed was greater when the protein intake was increased, the percentage of moisture remained relatively constant in the droppings—approximately 71 percent. Glista and Scott (1949) found that the gross water consumption increased
with soybean oil meal intake. Eley and Hoffman (1949) obtained no relationship between feed particle size, moisture content of droppings, water or feed consumption, or weight gains. Reported in this manuscript are data showing the influence of adding different protein concentrates to broiler rations on consumption and excretion of water and excreta voided by broiler chicks. EXPERIMENTAL
Broiler strain chicks were used during these studies. They were fed a regular broiler ration containing 21 percent protein until 5 weeks of age, then placed on the supplemented rations outlined in Tables 1 and 2. The supplemented rations were composed of the regular ration to which different protein concentrates had been added by replacing the corn meal to bring the protein level up to 27 percent.
Downloaded from http://ps.oxfordjournals.org/ at Purdue University Libraries ADMN on May 29, 2015
duces the moisture and protein content in proportion to their quantity in the fat-free material. Growth, fattening and sex do not affect the crude chemical composition as calculated on a fat-free basis, or from regression lines calculated from the fat content. The crude chemical composition of the breast muscle and the ash content of the total edible meat and leg muscle cannot be calculated from the regression equations with more than fair accuracy. The crude chemical composition of the total edible meat and leg muscle of poul-
155