- Email: [email protected]
Studies on Energy Levels in Poultry Rations
614
D. C. SHELTON, N. 0. OLSON AND C. E. WEAKLEY, JR.
Chas. Pfizer & Co., Inc., Terre Haute, Indiana for oxytetracycline hydrochloride and magnamycin; Shea Chemical Corporation, Baltimore, Maryland for dicalcium phosphate. REFERENCES
Studies on Energy Levels in Poultry Rations 3.
EFFECT OF CALORIE-PROTEIN RATIO OF THE RATION ON GROWTH, NUTRIENT UTILIZATION AND BODY COMPOSITION OF POULTS 1 W. E. DONALDSON,2 G. F. COMBS AND G. L. ROMOSER3 Department of Poultry Husbandry, University of Maryland, College Park (Received for publication October 24, 1957)
INTRODUCTION
G
ROWTH rate, feed consumption, body composition and feathering of broiler chickens have been shown to be influenced by the ratio of energy to protein 1 Scientific Article No. A653. Contribution No. 2843 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry). 2 Present address: Department of Poultry Husbandry, University of Rhode Island, Kingston, Rhode Island. 3 Present address: Monsanto Chemical Company, St. Louis, Missouri.
content of the ration (Baldini and Rosenberg, 1955; Combs and Romoser, 1955; Combs et al., 1955a, b; Donaldson et al., 1955, 1956; Leong et al., 1955; Matterson et al., 1955; Scott et al., 1955; and Sunde, 1956). More recently, similar observations have been made in studies with turkey rations. Lockhart and Thayer (1955) reported that poults grew best when fed a starting ration having a Calorie-protein ratio 4 of 29:1. Ferguson et al. (1956a) in4 Calories of productive energy per pound for each 1% (4.537 gms.) crude protein.
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Briggs, G. M., G. F. Combs, L. Friedman, J. C. Fritz, R. J. Lillie, F. W. Quackenbush and H. W. Titus, 1954. Standard chick and broiler diet. Animal Nutrition Research Council News Letter, Vol. 1: No. 2. Cosgrove, A. S., 1957. Laboratory and field studies with furazolidone in the prevention and treatment of avian infectious synovitis. J. Am. Vet. Med. Assoc. 130: 286-289. Cover, M. S., J. N. Galeta and E. F. Waller, 1956. The etiology of an arthritic disease of chickens. Am. J. Vet. Res. 17: 12-15. Munro, D. A., N. O. Olson and D. C. Shelton, 1956. Synovitis control. 5. Intramuscular streptomycin and a comparison of continuous and intermittent feeding of Aureomycin and furazolidone (nf-180). Poultry Sci. 35: 1161. Olson, N. O., D. C. Shelton, J. K. Bletner, D. A. Munro and G. C. Anderson, 1956. Studies of
infectious synovitis in chickens. Am. J. Vet. Res. 17: 747-754. Olson, N. 0., and D. C. Shelton, 1957. Infectious synovitis control. 8. Degree of infection and medication. Poultry Sci. 36: 1146. Olson, N. O., D. C. Shelton, J. K. Bletner and C. E. Weakley, Jr., 1957a. Infectious synovitis control. 2. A comparison of levels of antibiotics. Am. J. Vet. Res. 18: 200-203. Olson, N. O., D. C. Shelton and D. A. Munro, 1957b. Infectious synovitis control by medication. Effect of strain differences and pleuropneumonialike organisms. Am. J. Vet. Res. 18: 735-739. Peterson, E. H., R. Chalquest and H. G. Luther, 1955-56. Oxytetracycline in the prophylaxis of synovitis in experimentally infected chicks. Antibiotics Annual, 1955-56: 313-318. Medical Encyclopedia, Inc., New York, N. Y. Shelton, D. C , J. K. Bletner, N. O. Olson, G. C. Anderson and C. E. Weakley, Jr., 1957. Control of infectious synovitis. 1. Continuous feeding of antibiotics and the influence of diethylstilbestrol and coccidiostats. Poultry Sci. 36: 113— 121. Thayer, S. C , R. G. Stout and W. R. Dunlop, 1957. Observation of infectious synovitis. Poultry Sci. 36: 1163.
615
CALORIE-PROTEIN RATIO
The experiment reported in this paper also was designed to study energy and protein relationships in turkey starting rations. PROCEDURE
Fifteen groups of 15 day-old Maryland White poults (both sexes) were reared to four weeks of age in conventional battery brooders. Feed and water were available ad libitum. All poults were individually weighed at two and four weeks of age and feed consumption was recorded for the four-week period. Composition of the rations fed together with their calculated crude protein and productive energy contents is shown in Table 1. With the exception of protein,
TABLE 1.—Composition of rations used Diet Prot., % (calc.)
Prod.energy cal./lb. (calc.)
C/P ratio*
21.43 24.11 27.55 32.15 38.58
1,072 1,064 1,056 1,048 1,040
50.0 44.1 38.3 32.6 27.0
23.57 26.19 29.47 33.68 39.29
1,198 1,191 1,181 1,169 1,154
50.8 45.5 40.1 34.7 29.4
25.33 27.86 30.96 34.83 39.80
1,323 1,316 1,307 1,297 1,283
52.2 47.2 42.2 37.2 32.2
Prot. mix,f
%
Vit. mix,! Min. mix,§
%
3% added fat series 36.76 1.00 41.36 1.00 47.26 1.00 55.15 1.00 66.18 1.00 10.5% added fat series 1.00 40.44 44.93 1.00 50.55 1.00 57.78 1.00 67.41 1.00 18% added fat series 1.00 43.46 1.00 47.79 53.11 1.00 59.74 1.00 68.27 1.00
Glucose,
Corn oil,
%
%
%
5.68 5.68 5.68 5.68 5.68
53.56 48.96 43.06 35.17 24.14
3.0 3.0 3.0 3.0 3.0
5.68 5.68 5.68 5.68 5.68
42.38 37.89 32.27 25.04 15.41
10.5 10.5 10.5 10.5 10.5
5.68 5.68 5.68 5.68 5.68
31.86 27.53 22.21 15.58 7.05
18.0 18.0 18.0 18.0 18.0
* Calories of productive energy per pound for each percent (4.537 grams) crude protein. t The protein mixture consisted of: ground yellow corn, 25.68%; Drackett C-l assay protein, 41.91%; fish meal, menhaden, 60% protein, 22.66%; dried brewers' yeast, 7.55%; dehydrated alfalfa meal, 17% protein (100,000 I.U. of A/lb.), 1.51%; DL-methionine, 0.69%. I One pound of vitamin mix supplied the following amounts to 100 pounds of finished ration: (mg./lb.) riboflavin, 5.0; niacin, 25.0; calcium pantothenate, 25.0; pyridoxine, 3.0; folic acid, 0.6; biotin, 0.1; choline chloride, 1,008.0; menadione, 4.0; vitamin E acetate, 5.0; 50% procaine penicillin, 200.0; (mcg./lb) vitamin B12, 10.0; (%) diphenylparaphenylenediamine (DPPD), 0.025; dry vitamin A and D 3 supplement (4,000 I.U. of A and 7501.C.U. of D/gm.) ,0.3. § The mineral mixture consisted of: limestone (98% CaC0 3 ), 44.01%; K 2 HP0 4 , 2.20%; CaHP0 4 , 30.08%; Trace mineral mix (6% manganese, 0.12% iodine, 2 % iron, 0.2% copper, 0.006% zinc, 0.02% cobalt and 27% calcium), 4.35%; NaCl (0.007% iodine), 10.56%; MgS0 4 • 7H 2 0, 4.40%; dried fermentation product (Pfizer's Vigofac), 4.40%.
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dicated that the optimum Calorie-protein ratio for the turkey poult to eight weeks of age was between 25 and 31:1. In close agreement with this work is that of Atkinson et al. (1956) which indicates that up to eight weeks, the poult requires a protein level of 30 to 32% with a Calorie-protein ratio of 27 to 30:1 for optimum growth. In later work, Ferguson et al. (1956b) using a 26% protein ration obtained the best growth of poults to eight weeks with a Calorie-protein ratio of 29:1. In turkey finishing rations (eight to sixteen weeks), Yacowitz et al. (1956) found no differences in growth and feed efficiency with rations ranging from 20 to 26% protein and having Calorie-protein ratios ranging from 32 to 47:1.
616
W. E. DONALDSON, G. F. COMBS AND G. L. ROMOSER
At the conclusion of the experimental period, the three poults most closely approaching the average group weight were sacrificed from each group and then frozen at —20° C. until analyzed. The whole carcasses from each group were then ground together through an electric meat grinder and thoroughly mixed. Samples from each group were prepared and analyzed for moisture, ether extract and protein using the method of the A.O.A.C. (1945) for meat and meat products. All data presented are uncorrected for sex differences since sex was not determined at four weeks. RESULTS
The growth and feed consumption data obtained are presented in Table 2. As the
TABLE 2.—Effect of Calorie-protein ratio and fat level of the ration on growth and feed utilization of \ C/P ratio
27.0 32.6 38.3 44.1 50.0 29.4 34.7 40.1 45.5 50.8 32.2 37.2 42.2 47.2 52.2
Ave. 4wk. wt., gms.2
Feed/ gain
Cal. Gm. proPE/gm. tein/gm. gain gain
3% added corn oil 683 1.37 3.1 549* 1.35 3.1 516** 1.37 3.2 503** 1.45 3.5 458** 1.53 3.6 10.5% added corn oil 628 1.30 3.3 594 1.29 3.3 591 1.24 3.2 556 1.30 3.5 456** 1.36 3.6 18% added corn oil 650 1.14 3.2 662 1.10 3.1 622 1.14 3.2 606 1.19 3.5 492** 1.28 3.7
0.53 0.43 0.38 0.35 0.33 0.51 0.43 0.37 0.34 0.32 0.45 0.38 0.35 0.33 0.32
1 15 Maryland Medium White poults (both sexes) per group. 2 LSD *(P=0.05) is 112 grams; **(P = 0.01) is 162 grams.
Calorie-protein ratio was widened above 27.0:1 in the 3 % added corn oil series, the average four-week weights were significantly decreased. The same result was observed in the 10.5% added corn oil series; however, a significant reduction in weight was not evident until a Calorieprotein ratio of 45.5:1 was exceeded. In the 18% added corn oil series, significant reduction in weight was not observed until the Calorie-protein ratio exceeded 47.2:1. Although there was some variation, in general the feed consumed per gram gain increased as the Calorie-protein ratio increased within each fat series. Accordingly, the Calories of productive energy consumed per gram gain increased and the grams of protein consumed per gram gain decreased as the Calorie-protein ratio was widened. The carcass composition data are shown in Table 3. In general, as the Calorie-protein ratio was widened, carcass
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these rations were formulated to be adequate in all known and unidentified nutrients required by poults. The rations within each fat series are essentially isocaloric with changes in Calorie-protein ratio being accomplished by altering the proportions of protein mixture and glucose while the levels of mineral mix, vitamin mix and corn oil remained constant. Since the protein containing ingredients were always added in the same proportions to each other, the amino acid quality of the protein remained identical in all rations. The productive energy values of all ingredients except glucose, corn oil and Drackett C-l assay protein were based on the data of Fraps (1946). The value for glucose of 1156 Calories per pound was based on the data of Anderson (1955) corrected for moisture content while the 2,900 Calories per pound value for corn oil came from the data of Hill (1954). Drackett C-l assay protein was estimated to contain 1,050 Calories per pound by comparison with similar ingredients using Fraps data, since there is no published value for Drackett protein.
617
CALORIE-PROTEIN RATIO TABLE 3.—Effect
of Calorie-protein ratio and fat level of the ration on carcass composition of poults Added corn oil in diet, %
10.5
18
10.5
18
10.5
18
C/P ratio Carcass Composition, % Moisture
1
70.2
—
— —
69.7
— —
69.5
— —
69.2
— —
68.3
— —
69.4
70.7 70.7 70.9 70.5
— —
20.2
5.4 7.0
18.4 7.9
68.3
19.2 20.5
4.7 6.7
19.1
8.6
— —
17.9 20.3
5.1 7.3
— —
67.2
— —
67.8
19.3
9.5 8.1
18.3 17.5
9.6
18.3 13.0
8.2
—
14.9 17.9
11.0
16.4 9.0
18.6
NX6.25.
fat tended to increase slightly while carcass protein decreased slightly and carcass water remained unchanged. Calorieprotein ratio had less effect in altering composition than did fat level at Calorieprotein ratios narrower than 41:1. Higher fat levels increased body fat content while lowering body protein and body water content. DISCUSSION
In this study, Calorie-protein ratios in excess of 27.0:1 impaired growth of poults to four weeks when the fat level of the ration was only 3 % . At higher fat levels (10.5 and 18% added) wider ratios of approximately 45.5 and 47.2:1, respectively, were tolerated before growth impairment occurred. Furthermore, the carcass composition data show a trend toward in creased fat deposition as the Calorie-protein ratio was widened within each fat level. A combination of the growth and carcass composition data indicates that as the Calorie-protein ratio of the ration is widened, poults consume relatively more energy in an effort to obtain other re-
quired nutrients (presumably certain amino acids) with the additional consumed energy being deposited in the carcass as fat. However, within each fat level, when the imbalance of energy to protein became so wide that the poults could not overconsume enough energy to meet their needs for amino acids, growth was impaired. An interesting observation is that the poults fed the higher fat rations could tolerate wider Calorie-protein ratios before growth was adversely affected than could poults fed the 3 % added fat rations. That this effect of fat can be explained on the basis of an over-estimation of the productive energy content of fat is not likely. Productive energy values of 2,100, 2,878 and 2,900 Calories per pound for different fats have been proposed by Fraps (1946), Titus (1955) and Hill (1954), respectively. As was pointed out earlier, the value of Hill was used in this experiment. The data presented herein would require a value of approximately 1,470 Calories per pound for fat (an over-estimation of 100%) to eliminate the apparent bene-
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27.0 29.4 32.2 32.6 34.7 37.2 38.3 40.1 42.2 44.1 45.5 47.2 50.0 50.8 52.2
Protein 1
Ether Extract
618
W. E. DONALDSON, G. F. COMBS AND G. L. ROMOSER
Since less protein was required per gram gain as the Calorie-protein ratio was increased, a sparing effect of energy on protein is indicated. At Calorie-protein ratios beyond approximately 40:1, there was an increase in the number of Calories required per gram gain as expected. That the Calorie intake per unit of gain was increased more than can be explained on the basis of an increased energy maintenance requirement per unit of gain as the C/P ratio was widened and rate of gain decreased, is evident from the accompanying increase in carcass fat content. At the same time, less protein was consumed per unit of gain. At ratios narrower than 40:1, Calorie requirements for growth were more or less constant. This result would also be expected since there was no change in body composition within fat levels as the Calorie-protein ratio increased up to 40:1. Since each gram of growth within a fat level was comparable in composition at ratios below 40:1, each gram of growth must also have represented comparable energy content. If the energy content of a gram of growth is constant, it follows that
the dietary energy consumed to produce each gram of growth must also be constant. The results of this study are in excellent agreement with those of Donaldson et al. (1956), with the exception of the observations on body composition as outlined above. In work with chicks, as Calorieprotein ratio was widened, less dietary protein and more dietary energy were required per unit of gain. In addition, at any protein level, a wider ratio of productive energy to protein in the ration was tolerated, without adversely affecting growth rate, as the proportion of Calories from dietary fat to those from other sources was increased. These results also support the work of Lockhart and Thayer (1955), Ferguson et al. (1956a, b) and Atkinson et al. (1956) all of whom reported most rapid growth of poults to eight weeks when the Calorieprotein ratio was within a range of 25 to 31:1. The lack of exact agreement can best be attributed to a combination of two factors. First, fat level may affect the growth rate at any given Calorie-protein ratio based on the results on the study; and second, differences in protein quality of the protein mixtures used could have an influence on the ratio at which optimum results are obtained. SUMMARY
In an experiment with poults reared to four weeks of age, growth was reduced as the ratio of productive energy to crude protein was raised above 27.0, 45.5 and 47.2 Calories of productive energy per pound for each 1% of crude protein in 3, 10.5 and 18% added corn oil rations, respectively. Feed consumed per gram gain increased as the ratio of productive energy to protein was widened within each fat series. Calories consumed per gram gain were constant at ratios nar-
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ficial effect of fat on growth. A more likely explanation is that the poult is able to convert more dietary energy from fat into stored energy (carcass fat), than from other sources, thereby permitting a greater increase in dietary energy intake when protein level is sub-optimal. This is borne out by the fact that at comparable Calorie-protein ratios, carcass fat content of the poults increased with increasing fat level while carcass protein and water contents decreased. These data also indicate that there is a species specificity in the efficiency of utilization of fat for synthesis of body tissue since Donaldson et al. (1956) showed that in chicks, body composition is primarily determined by the Calorie-protein ratio of the ration and that fat level has no effect.
CALORIE-PROTEIN RATIO
REFERENCES Anderson, D. L., 1955. Comparative studies on the determination of metabolizable and productive energy with the growing chick. Ph.D. thesis, Cornell University. Atkinson, R. L., J. H. Quisenberry and J. R. Couch, 1956. Protein and energy levels for growing turkeys. Poultry Sci. 35: 1131. Baldini, J. T., and H. R. Rosenberg, 1955. The effect of productive energy level of the diet on the methionine requirement of the chick. Poultry Sci. 34: 1301. Combs, G. F., and G. L. Romoser, 1955. A new approach to poultry feed formulation. Maryland Agr. Exp. Sta. Misc. Publ. No. 226. Combs, G. F., G. L. Romoser and J. L. Nicholson, 1955 a. Effect of debeaking and Calorie-protein ratio of rations for New Hampshire and crossbred broilers. Maryland Agr. Exp. Sta. Misc. Publ. No. 237. Combs, G. F., G. L. Romoser and J. L. Nicholson, 1955b. Effect of Calorie-protein ratio and methionine level in rations fed to crossbred broilers. Maryland Agr. Exp. Sta. Misc. Publ. No. 257. Donaldson, W. E., G. F. Combs, G. L. Romoser and W. C. Supplee, 1955. Body composition, energy intake, feed efficiency, growth rate, and feather condition of growing chickens as influenced by
Calorie-protein ratio of the ration. Poultry Sci. 34: 1190. Donaldson, W. E., G. F. Combs and G. L. Romoser, 1956. Studies on energy levels in poultry rations. 1. The effect of Calorie-protein ratio of the ration on growth, nutrient utilization and body composition of chicks. Poultry Sci. 35: 1100. Ferguson, T. M., H. P. Vaught, B. L. Reid and J. R. Couch, 1956a. The effect of amino acid supplements to the diet of Broad Breasted Bronze turkey poults fed various levels of protein and productive energy. Poultry Sci. 35: 1069. Ferguson, T. M., H. P. Vaught, L. D. Matterson, B. L. Reid and J. R. Couch, 1956b. Growth of Broad Breasted Bronze turkey poults fed a 26 percent protein diet with different levels of productive energy. Poultry Sci. 35: 1305. Fraps, G. S., 1946. Composition and productive energy of poultry feeds and rations. Texas Agr. Exp. Sta. Bull. No. 678. Hill, F. W., 1954. Energy and fat in rations for layers. Cornell Feed Service, 44: 8. Leong, K. C , M. L. Sunde, H. R. Bird and C. A. Elvehjem, 1955. Effect of energy:protein ratio on growth rate, efficiency, feathering and fat deposition in chickens. Poultry Sci. 34: 1206. Lockhart, W. C , and R. H. Thayer, 1955. Energyprotein relationships in poult turkey starters. Poultry Sci. 34: 1208. Matterson, L. D., L. M. Potter, L. D. Stinson and E. P. Singsen, 1955. Studies on the effect of varying protein and energy levels in poultry rations on growth and feed efficiency. Poultry Sci. 34: 1210. Official and Tentative Methods of Analysis of the A.O.A.C., 1945. A.O.A.C, Washington, D. C. Scott, H. M., L. C. Sims and D. L. Slakeli, 1955. The effect of varying protein and energy on performance of chicks. Poultry Sci. 34: 1220. Sunde, M. L., 1956. A relationship between protein level and energy level in chick rations. Poultry Sci. 35: 350. Titus, H. W., 1955. The Scientific Feeding of Chickens. The Interstate Printers and Publishers, Inc., Danville, Illinois. Yacowitz, H., R. Carter, J. Wyne and M. G. McCartney, 1956. Effects of varying protein and fat levels in a finishing ration for turkey broilers. Poultry Sci. 35: 227. •
SEPTEMBER 21-28. WORLD'S POULTRY CONGRESS, MEXICO CITY, MEXICO
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rower than 40 Calories of productive energy per pound for each 1% crude protein but increased as the ratio was widened beyond 40:1. Less protein was consumed per gram gain as the ratio of energy to protein was widened. Increased ratio also resulted in increased carcass fat, decreased carcass protein and unchanged carcass water contents. Increased dietary fat level caused increased fat content and decreased protein and water contents of the carcass. Productive energy to crude protein ratio (below 41:1) appeared to have less effect in altering carcass composition than did fat level.
619
D. C. SHELTON, N. 0. OLSON AND C. E. WEAKLEY, JR.
Chas. Pfizer & Co., Inc., Terre Haute, Indiana for oxytetracycline hydrochloride and magnamycin; Shea Chemical Corporation, Baltimore, Maryland for dicalcium phosphate. REFERENCES
Studies on Energy Levels in Poultry Rations 3.
EFFECT OF CALORIE-PROTEIN RATIO OF THE RATION ON GROWTH, NUTRIENT UTILIZATION AND BODY COMPOSITION OF POULTS 1 W. E. DONALDSON,2 G. F. COMBS AND G. L. ROMOSER3 Department of Poultry Husbandry, University of Maryland, College Park (Received for publication October 24, 1957)
INTRODUCTION
G
ROWTH rate, feed consumption, body composition and feathering of broiler chickens have been shown to be influenced by the ratio of energy to protein 1 Scientific Article No. A653. Contribution No. 2843 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry). 2 Present address: Department of Poultry Husbandry, University of Rhode Island, Kingston, Rhode Island. 3 Present address: Monsanto Chemical Company, St. Louis, Missouri.
content of the ration (Baldini and Rosenberg, 1955; Combs and Romoser, 1955; Combs et al., 1955a, b; Donaldson et al., 1955, 1956; Leong et al., 1955; Matterson et al., 1955; Scott et al., 1955; and Sunde, 1956). More recently, similar observations have been made in studies with turkey rations. Lockhart and Thayer (1955) reported that poults grew best when fed a starting ration having a Calorie-protein ratio 4 of 29:1. Ferguson et al. (1956a) in4 Calories of productive energy per pound for each 1% (4.537 gms.) crude protein.
Downloaded from http://ps.oxfordjournals.org/ at University of Birmingham on June 1, 2015
Briggs, G. M., G. F. Combs, L. Friedman, J. C. Fritz, R. J. Lillie, F. W. Quackenbush and H. W. Titus, 1954. Standard chick and broiler diet. Animal Nutrition Research Council News Letter, Vol. 1: No. 2. Cosgrove, A. S., 1957. Laboratory and field studies with furazolidone in the prevention and treatment of avian infectious synovitis. J. Am. Vet. Med. Assoc. 130: 286-289. Cover, M. S., J. N. Galeta and E. F. Waller, 1956. The etiology of an arthritic disease of chickens. Am. J. Vet. Res. 17: 12-15. Munro, D. A., N. O. Olson and D. C. Shelton, 1956. Synovitis control. 5. Intramuscular streptomycin and a comparison of continuous and intermittent feeding of Aureomycin and furazolidone (nf-180). Poultry Sci. 35: 1161. Olson, N. O., D. C. Shelton, J. K. Bletner, D. A. Munro and G. C. Anderson, 1956. Studies of
infectious synovitis in chickens. Am. J. Vet. Res. 17: 747-754. Olson, N. 0., and D. C. Shelton, 1957. Infectious synovitis control. 8. Degree of infection and medication. Poultry Sci. 36: 1146. Olson, N. O., D. C. Shelton, J. K. Bletner and C. E. Weakley, Jr., 1957a. Infectious synovitis control. 2. A comparison of levels of antibiotics. Am. J. Vet. Res. 18: 200-203. Olson, N. O., D. C. Shelton and D. A. Munro, 1957b. Infectious synovitis control by medication. Effect of strain differences and pleuropneumonialike organisms. Am. J. Vet. Res. 18: 735-739. Peterson, E. H., R. Chalquest and H. G. Luther, 1955-56. Oxytetracycline in the prophylaxis of synovitis in experimentally infected chicks. Antibiotics Annual, 1955-56: 313-318. Medical Encyclopedia, Inc., New York, N. Y. Shelton, D. C , J. K. Bletner, N. O. Olson, G. C. Anderson and C. E. Weakley, Jr., 1957. Control of infectious synovitis. 1. Continuous feeding of antibiotics and the influence of diethylstilbestrol and coccidiostats. Poultry Sci. 36: 113— 121. Thayer, S. C , R. G. Stout and W. R. Dunlop, 1957. Observation of infectious synovitis. Poultry Sci. 36: 1163.
615
CALORIE-PROTEIN RATIO
The experiment reported in this paper also was designed to study energy and protein relationships in turkey starting rations. PROCEDURE
Fifteen groups of 15 day-old Maryland White poults (both sexes) were reared to four weeks of age in conventional battery brooders. Feed and water were available ad libitum. All poults were individually weighed at two and four weeks of age and feed consumption was recorded for the four-week period. Composition of the rations fed together with their calculated crude protein and productive energy contents is shown in Table 1. With the exception of protein,
TABLE 1.—Composition of rations used Diet Prot., % (calc.)
Prod.energy cal./lb. (calc.)
C/P ratio*
21.43 24.11 27.55 32.15 38.58
1,072 1,064 1,056 1,048 1,040
50.0 44.1 38.3 32.6 27.0
23.57 26.19 29.47 33.68 39.29
1,198 1,191 1,181 1,169 1,154
50.8 45.5 40.1 34.7 29.4
25.33 27.86 30.96 34.83 39.80
1,323 1,316 1,307 1,297 1,283
52.2 47.2 42.2 37.2 32.2
Prot. mix,f
%
Vit. mix,! Min. mix,§
%
3% added fat series 36.76 1.00 41.36 1.00 47.26 1.00 55.15 1.00 66.18 1.00 10.5% added fat series 1.00 40.44 44.93 1.00 50.55 1.00 57.78 1.00 67.41 1.00 18% added fat series 1.00 43.46 1.00 47.79 53.11 1.00 59.74 1.00 68.27 1.00
Glucose,
Corn oil,
%
%
%
5.68 5.68 5.68 5.68 5.68
53.56 48.96 43.06 35.17 24.14
3.0 3.0 3.0 3.0 3.0
5.68 5.68 5.68 5.68 5.68
42.38 37.89 32.27 25.04 15.41
10.5 10.5 10.5 10.5 10.5
5.68 5.68 5.68 5.68 5.68
31.86 27.53 22.21 15.58 7.05
18.0 18.0 18.0 18.0 18.0
* Calories of productive energy per pound for each percent (4.537 grams) crude protein. t The protein mixture consisted of: ground yellow corn, 25.68%; Drackett C-l assay protein, 41.91%; fish meal, menhaden, 60% protein, 22.66%; dried brewers' yeast, 7.55%; dehydrated alfalfa meal, 17% protein (100,000 I.U. of A/lb.), 1.51%; DL-methionine, 0.69%. I One pound of vitamin mix supplied the following amounts to 100 pounds of finished ration: (mg./lb.) riboflavin, 5.0; niacin, 25.0; calcium pantothenate, 25.0; pyridoxine, 3.0; folic acid, 0.6; biotin, 0.1; choline chloride, 1,008.0; menadione, 4.0; vitamin E acetate, 5.0; 50% procaine penicillin, 200.0; (mcg./lb) vitamin B12, 10.0; (%) diphenylparaphenylenediamine (DPPD), 0.025; dry vitamin A and D 3 supplement (4,000 I.U. of A and 7501.C.U. of D/gm.) ,0.3. § The mineral mixture consisted of: limestone (98% CaC0 3 ), 44.01%; K 2 HP0 4 , 2.20%; CaHP0 4 , 30.08%; Trace mineral mix (6% manganese, 0.12% iodine, 2 % iron, 0.2% copper, 0.006% zinc, 0.02% cobalt and 27% calcium), 4.35%; NaCl (0.007% iodine), 10.56%; MgS0 4 • 7H 2 0, 4.40%; dried fermentation product (Pfizer's Vigofac), 4.40%.
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dicated that the optimum Calorie-protein ratio for the turkey poult to eight weeks of age was between 25 and 31:1. In close agreement with this work is that of Atkinson et al. (1956) which indicates that up to eight weeks, the poult requires a protein level of 30 to 32% with a Calorie-protein ratio of 27 to 30:1 for optimum growth. In later work, Ferguson et al. (1956b) using a 26% protein ration obtained the best growth of poults to eight weeks with a Calorie-protein ratio of 29:1. In turkey finishing rations (eight to sixteen weeks), Yacowitz et al. (1956) found no differences in growth and feed efficiency with rations ranging from 20 to 26% protein and having Calorie-protein ratios ranging from 32 to 47:1.
616
W. E. DONALDSON, G. F. COMBS AND G. L. ROMOSER
At the conclusion of the experimental period, the three poults most closely approaching the average group weight were sacrificed from each group and then frozen at —20° C. until analyzed. The whole carcasses from each group were then ground together through an electric meat grinder and thoroughly mixed. Samples from each group were prepared and analyzed for moisture, ether extract and protein using the method of the A.O.A.C. (1945) for meat and meat products. All data presented are uncorrected for sex differences since sex was not determined at four weeks. RESULTS
The growth and feed consumption data obtained are presented in Table 2. As the
TABLE 2.—Effect of Calorie-protein ratio and fat level of the ration on growth and feed utilization of \ C/P ratio
27.0 32.6 38.3 44.1 50.0 29.4 34.7 40.1 45.5 50.8 32.2 37.2 42.2 47.2 52.2
Ave. 4wk. wt., gms.2
Feed/ gain
Cal. Gm. proPE/gm. tein/gm. gain gain
3% added corn oil 683 1.37 3.1 549* 1.35 3.1 516** 1.37 3.2 503** 1.45 3.5 458** 1.53 3.6 10.5% added corn oil 628 1.30 3.3 594 1.29 3.3 591 1.24 3.2 556 1.30 3.5 456** 1.36 3.6 18% added corn oil 650 1.14 3.2 662 1.10 3.1 622 1.14 3.2 606 1.19 3.5 492** 1.28 3.7
0.53 0.43 0.38 0.35 0.33 0.51 0.43 0.37 0.34 0.32 0.45 0.38 0.35 0.33 0.32
1 15 Maryland Medium White poults (both sexes) per group. 2 LSD *(P=0.05) is 112 grams; **(P = 0.01) is 162 grams.
Calorie-protein ratio was widened above 27.0:1 in the 3 % added corn oil series, the average four-week weights were significantly decreased. The same result was observed in the 10.5% added corn oil series; however, a significant reduction in weight was not evident until a Calorieprotein ratio of 45.5:1 was exceeded. In the 18% added corn oil series, significant reduction in weight was not observed until the Calorie-protein ratio exceeded 47.2:1. Although there was some variation, in general the feed consumed per gram gain increased as the Calorie-protein ratio increased within each fat series. Accordingly, the Calories of productive energy consumed per gram gain increased and the grams of protein consumed per gram gain decreased as the Calorie-protein ratio was widened. The carcass composition data are shown in Table 3. In general, as the Calorie-protein ratio was widened, carcass
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these rations were formulated to be adequate in all known and unidentified nutrients required by poults. The rations within each fat series are essentially isocaloric with changes in Calorie-protein ratio being accomplished by altering the proportions of protein mixture and glucose while the levels of mineral mix, vitamin mix and corn oil remained constant. Since the protein containing ingredients were always added in the same proportions to each other, the amino acid quality of the protein remained identical in all rations. The productive energy values of all ingredients except glucose, corn oil and Drackett C-l assay protein were based on the data of Fraps (1946). The value for glucose of 1156 Calories per pound was based on the data of Anderson (1955) corrected for moisture content while the 2,900 Calories per pound value for corn oil came from the data of Hill (1954). Drackett C-l assay protein was estimated to contain 1,050 Calories per pound by comparison with similar ingredients using Fraps data, since there is no published value for Drackett protein.
617
CALORIE-PROTEIN RATIO TABLE 3.—Effect
of Calorie-protein ratio and fat level of the ration on carcass composition of poults Added corn oil in diet, %
10.5
18
10.5
18
10.5
18
C/P ratio Carcass Composition, % Moisture
1
70.2
—
— —
69.7
— —
69.5
— —
69.2
— —
68.3
— —
69.4
70.7 70.7 70.9 70.5
— —
20.2
5.4 7.0
18.4 7.9
68.3
19.2 20.5
4.7 6.7
19.1
8.6
— —
17.9 20.3
5.1 7.3
— —
67.2
— —
67.8
19.3
9.5 8.1
18.3 17.5
9.6
18.3 13.0
8.2
—
14.9 17.9
11.0
16.4 9.0
18.6
NX6.25.
fat tended to increase slightly while carcass protein decreased slightly and carcass water remained unchanged. Calorieprotein ratio had less effect in altering composition than did fat level at Calorieprotein ratios narrower than 41:1. Higher fat levels increased body fat content while lowering body protein and body water content. DISCUSSION
In this study, Calorie-protein ratios in excess of 27.0:1 impaired growth of poults to four weeks when the fat level of the ration was only 3 % . At higher fat levels (10.5 and 18% added) wider ratios of approximately 45.5 and 47.2:1, respectively, were tolerated before growth impairment occurred. Furthermore, the carcass composition data show a trend toward in creased fat deposition as the Calorie-protein ratio was widened within each fat level. A combination of the growth and carcass composition data indicates that as the Calorie-protein ratio of the ration is widened, poults consume relatively more energy in an effort to obtain other re-
quired nutrients (presumably certain amino acids) with the additional consumed energy being deposited in the carcass as fat. However, within each fat level, when the imbalance of energy to protein became so wide that the poults could not overconsume enough energy to meet their needs for amino acids, growth was impaired. An interesting observation is that the poults fed the higher fat rations could tolerate wider Calorie-protein ratios before growth was adversely affected than could poults fed the 3 % added fat rations. That this effect of fat can be explained on the basis of an over-estimation of the productive energy content of fat is not likely. Productive energy values of 2,100, 2,878 and 2,900 Calories per pound for different fats have been proposed by Fraps (1946), Titus (1955) and Hill (1954), respectively. As was pointed out earlier, the value of Hill was used in this experiment. The data presented herein would require a value of approximately 1,470 Calories per pound for fat (an over-estimation of 100%) to eliminate the apparent bene-
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27.0 29.4 32.2 32.6 34.7 37.2 38.3 40.1 42.2 44.1 45.5 47.2 50.0 50.8 52.2
Protein 1
Ether Extract
618
W. E. DONALDSON, G. F. COMBS AND G. L. ROMOSER
Since less protein was required per gram gain as the Calorie-protein ratio was increased, a sparing effect of energy on protein is indicated. At Calorie-protein ratios beyond approximately 40:1, there was an increase in the number of Calories required per gram gain as expected. That the Calorie intake per unit of gain was increased more than can be explained on the basis of an increased energy maintenance requirement per unit of gain as the C/P ratio was widened and rate of gain decreased, is evident from the accompanying increase in carcass fat content. At the same time, less protein was consumed per unit of gain. At ratios narrower than 40:1, Calorie requirements for growth were more or less constant. This result would also be expected since there was no change in body composition within fat levels as the Calorie-protein ratio increased up to 40:1. Since each gram of growth within a fat level was comparable in composition at ratios below 40:1, each gram of growth must also have represented comparable energy content. If the energy content of a gram of growth is constant, it follows that
the dietary energy consumed to produce each gram of growth must also be constant. The results of this study are in excellent agreement with those of Donaldson et al. (1956), with the exception of the observations on body composition as outlined above. In work with chicks, as Calorieprotein ratio was widened, less dietary protein and more dietary energy were required per unit of gain. In addition, at any protein level, a wider ratio of productive energy to protein in the ration was tolerated, without adversely affecting growth rate, as the proportion of Calories from dietary fat to those from other sources was increased. These results also support the work of Lockhart and Thayer (1955), Ferguson et al. (1956a, b) and Atkinson et al. (1956) all of whom reported most rapid growth of poults to eight weeks when the Calorieprotein ratio was within a range of 25 to 31:1. The lack of exact agreement can best be attributed to a combination of two factors. First, fat level may affect the growth rate at any given Calorie-protein ratio based on the results on the study; and second, differences in protein quality of the protein mixtures used could have an influence on the ratio at which optimum results are obtained. SUMMARY
In an experiment with poults reared to four weeks of age, growth was reduced as the ratio of productive energy to crude protein was raised above 27.0, 45.5 and 47.2 Calories of productive energy per pound for each 1% of crude protein in 3, 10.5 and 18% added corn oil rations, respectively. Feed consumed per gram gain increased as the ratio of productive energy to protein was widened within each fat series. Calories consumed per gram gain were constant at ratios nar-
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ficial effect of fat on growth. A more likely explanation is that the poult is able to convert more dietary energy from fat into stored energy (carcass fat), than from other sources, thereby permitting a greater increase in dietary energy intake when protein level is sub-optimal. This is borne out by the fact that at comparable Calorie-protein ratios, carcass fat content of the poults increased with increasing fat level while carcass protein and water contents decreased. These data also indicate that there is a species specificity in the efficiency of utilization of fat for synthesis of body tissue since Donaldson et al. (1956) showed that in chicks, body composition is primarily determined by the Calorie-protein ratio of the ration and that fat level has no effect.
CALORIE-PROTEIN RATIO
REFERENCES Anderson, D. L., 1955. Comparative studies on the determination of metabolizable and productive energy with the growing chick. Ph.D. thesis, Cornell University. Atkinson, R. L., J. H. Quisenberry and J. R. Couch, 1956. Protein and energy levels for growing turkeys. Poultry Sci. 35: 1131. Baldini, J. T., and H. R. Rosenberg, 1955. The effect of productive energy level of the diet on the methionine requirement of the chick. Poultry Sci. 34: 1301. Combs, G. F., and G. L. Romoser, 1955. A new approach to poultry feed formulation. Maryland Agr. Exp. Sta. Misc. Publ. No. 226. Combs, G. F., G. L. Romoser and J. L. Nicholson, 1955 a. Effect of debeaking and Calorie-protein ratio of rations for New Hampshire and crossbred broilers. Maryland Agr. Exp. Sta. Misc. Publ. No. 237. Combs, G. F., G. L. Romoser and J. L. Nicholson, 1955b. Effect of Calorie-protein ratio and methionine level in rations fed to crossbred broilers. Maryland Agr. Exp. Sta. Misc. Publ. No. 257. Donaldson, W. E., G. F. Combs, G. L. Romoser and W. C. Supplee, 1955. Body composition, energy intake, feed efficiency, growth rate, and feather condition of growing chickens as influenced by
Calorie-protein ratio of the ration. Poultry Sci. 34: 1190. Donaldson, W. E., G. F. Combs and G. L. Romoser, 1956. Studies on energy levels in poultry rations. 1. The effect of Calorie-protein ratio of the ration on growth, nutrient utilization and body composition of chicks. Poultry Sci. 35: 1100. Ferguson, T. M., H. P. Vaught, B. L. Reid and J. R. Couch, 1956a. The effect of amino acid supplements to the diet of Broad Breasted Bronze turkey poults fed various levels of protein and productive energy. Poultry Sci. 35: 1069. Ferguson, T. M., H. P. Vaught, L. D. Matterson, B. L. Reid and J. R. Couch, 1956b. Growth of Broad Breasted Bronze turkey poults fed a 26 percent protein diet with different levels of productive energy. Poultry Sci. 35: 1305. Fraps, G. S., 1946. Composition and productive energy of poultry feeds and rations. Texas Agr. Exp. Sta. Bull. No. 678. Hill, F. W., 1954. Energy and fat in rations for layers. Cornell Feed Service, 44: 8. Leong, K. C , M. L. Sunde, H. R. Bird and C. A. Elvehjem, 1955. Effect of energy:protein ratio on growth rate, efficiency, feathering and fat deposition in chickens. Poultry Sci. 34: 1206. Lockhart, W. C , and R. H. Thayer, 1955. Energyprotein relationships in poult turkey starters. Poultry Sci. 34: 1208. Matterson, L. D., L. M. Potter, L. D. Stinson and E. P. Singsen, 1955. Studies on the effect of varying protein and energy levels in poultry rations on growth and feed efficiency. Poultry Sci. 34: 1210. Official and Tentative Methods of Analysis of the A.O.A.C., 1945. A.O.A.C, Washington, D. C. Scott, H. M., L. C. Sims and D. L. Slakeli, 1955. The effect of varying protein and energy on performance of chicks. Poultry Sci. 34: 1220. Sunde, M. L., 1956. A relationship between protein level and energy level in chick rations. Poultry Sci. 35: 350. Titus, H. W., 1955. The Scientific Feeding of Chickens. The Interstate Printers and Publishers, Inc., Danville, Illinois. Yacowitz, H., R. Carter, J. Wyne and M. G. McCartney, 1956. Effects of varying protein and fat levels in a finishing ration for turkey broilers. Poultry Sci. 35: 227. •
SEPTEMBER 21-28. WORLD'S POULTRY CONGRESS, MEXICO CITY, MEXICO
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rower than 40 Calories of productive energy per pound for each 1% crude protein but increased as the ratio was widened beyond 40:1. Less protein was consumed per gram gain as the ratio of energy to protein was widened. Increased ratio also resulted in increased carcass fat, decreased carcass protein and unchanged carcass water contents. Increased dietary fat level caused increased fat content and decreased protein and water contents of the carcass. Productive energy to crude protein ratio (below 41:1) appeared to have less effect in altering carcass composition than did fat level.
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