Interrelationships among Dietary Energy, Protein, and Amino Acids for Chickens1

Interrelationships among Dietary Energy, Protein, and Amino Acids for Chickens 1 K.

C. L E O N G , 2 M. L. S U N D E , H. R. B I R D AND C. A.

ELVEHJEM

University of Wisconsin, Madison, Wisconsin (Received for pub lication March 30, 1959)

T

Published with the approval of the Director of the Wisconsin Agricultural Experiment Station, College of Agriculture, Madison, Wisconsin. 1 Supported in part by a grant from E. I. DuPont de Nemours and Co., Wilmington, Delaware. 2 Present address: Department of Poultry Science, State College of Washington, Pullman, Washington.

1956). Use of fats seemed to lead to a deficiency of some nutrients, especially when nutrients were added percentagewise and the feed intake decreased with the rise in energy content of the rations. This led Sunde (1954) to suggest that with fat incorporation, the rations should be reevaluated and the percentage of protein carriers increased. The results of several workers (Yacowitz, 1953; March and Biely, 1954; and Hill and Dansky, 1954), added credence to this statement. Yacowitz (1953) found that increasing the levels of added fat from 2.5 and 5 percent to 10 and 15 percent with protein kept constant, induced signs of protein deficiency such as retarded growth and high incidence of feather picking. Hill and Dansky (1954) lowered the energy level in a low protein diet and restored the chick growth rate. March and Biely (1954) indicated that additions of fat to a low protein diet caused a depression in growth, but the same additions to a high protein diet improved growth rate. These results showed the importance of the energy-toprotein relationship. The objectives of the series of experiments reported here were: to explore the energy-to-protein ratio in unsupplemented diets and in diets supplemented with amino acids to improve protein quality; to determine the effect of varying energy and protein levels on the requirement for the first limiting amino acid, methionine plus cystine; and to determine the effect of the aforementioned dietary variables on body composition of young chickens.

1267

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HE economical availability of fats for animal feeding made it possible to increase the energy content of poultry rations. Scott et al. (1947) had reported that rations high in energy content promoted more rapid growth and better feed efficiency in chickens than those of lower energy. Henderson and Irwin (1940) reported that up to 10 percent of soybean oil could be fed to chicks without affecting the rate of growth to eight weeks of age. Greater amounts resulted in deleterious effects. More recent workers (Siedler and Schweigert, 1953; Sunde, 1954; Runnels, 1954; and Donaldson et al., 1954) reported improvements in feed efficiency but not in growth rate. On the other hand, substantial chick growth improvements were noted by other workers (Robertson et al., 1948; Kummerow, 1949; Carver and Johnson, 1953; Pepper et al., 1953; Yacowitz, 1953; Yacowitz and Chamberlin, 1954; and Donaldson et al., 1956) with additions of fat to the rations. Some workers also reported that with the addition of fats, the requirement of chicks for choline, riboflavin, folic acid and methionine increased (Kummerow et al., 1949; Reiser and Pearson, 1949; Donaldson et al, 1954; and March and Biely, 1954,

1268

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHJEM PROCEDURE

Calculation for productive energy of feed ingredients was taken from Fraps (1946). A productive energy value of 2,900 Calories was used for fat based on the work of Hill and Dansky (1954). RESULTS AND DISCUSSION

Experiment 3. Day-old straight run New

Grams 1250

.

Fig. 1. Average weights of 9-week-old groups fed different energy and protein levels. Experiment 3.

Hampshire X Single Comb White Leghorn cross-bred chicks were used in this nine week experiment. Crude protein levels of the experimental diets ranged from 17 percent to 42 percent at 5 percent intervals. Calorie levels were 950, 1,210, and 1,450 Calories of productive energy per pound of feed. Depot fat was measured upon evisceration of the nine week old New York dressed birds. The birds were split down the back bone and all the visceral fat from the abdomen and around the intestine and gizzard was removed and weighed. In this experiment as the energy level rises the protein requirement in percentage also rises. The best growth obtained at 1,450 Calories was with 32 percent protein in the diet (Figure 1). Optimum growth at 1,210 Calories was with protein levels of 27 percent and 32 percent. Through interpolation by extending the two lines in the 1,210 Calorie growth curve in Figure 1, one obtains at the point of interception 29

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Unless otherwise noted, the following procedure was used for the series of experiments reported. Day-old male Arbor Acre White Rock chicks were housed in electrically heated battery brooders; and water and the experimental diets were supplied ad libitum. Birds were kept on experiment until they reached about three pounds live weight. They were transferred to unheated growing batteries at four weeks of age. Weekly weight and feed consumption were recorded. A protein mixture of one part fish meal, one part gelatin, and three parts of crude casein was used. The fat used was stabilized inedible choice white grease from pork and possibly some beef waste. It was stabilized with butylated hydroxytoluene, butylated hydroxyanisol, and citric acid. The experimental diets, as shown in Tables 1 and 2, differed from each other in energy content and protein level. The variations in energy content of the diets were brought about by varying the amounts of corn and cerelose with cellulose (Alphacel) and inedible choice white grease in the diets. Protein levels of the diets were varied by varying the amount of protein mixture with the amount of corn in the diets. Since the high-protein ingredients were added in the same proportions to each other as a mixture, the amino acid make-up of the dietary protein remained constant except as it was affected by the relatively small changes in levels of corn protein.

Alphacel White Grease 2 Protein Mixture Constant Ingredients 3

Ground yellow corn

2

1,210 17

101.1

47 24 0 8 15 7.1

950

101.1

22 10 0

3

1,450

101.1

10 0 22

4

5

1,210 22

101.1

40.5 24 0 8 21.5 7.1

950

101.1

22 10 0

61

1,450

101.1

10 0 22

7

8

1,210 27

101.1

33.5 24 0 8 28.5 7.1

950

101.1

22 10 0

91

1,450

101.1

10 0 22

10

11

1,210 32

101.1

27 24 0 8 35 7.1

950

101.1

22 10 0

121

1,450

101.1

10 0 22

13

1,210 37

101.1

20 24 0 8 42 7.1

14

950

101.1

22 10 0

151

1,450

101.1

10 0 22

16

1,210 42

101.1

16 24 0 8 46 7.1

17

950

101.1

22 10 0

181

101.1

0 3 25

1

1,210 17

.833 .2

.30

101.1

51 13.5 3 11.5 15 7.1

2

950

.30

101.1

20 8 0

31

1,450

.25

101.1

0 2 26

4

'

5

1,210 22

.682 .2

.25

101.1

44.5 14.5 2 11.5 21.5 7.1

950

.25

101.1

21.5 6.5 0

61-

1,450

1.191

.35

101.1

1 1 26

7

.21

101.1

23.5 4.5 0

91

.24

101.1

2 0 26

10

11

.24

101.1

31 16 0 12 35 7.1

.14

101.1

24 4 0

121

.25

101.1

1 0 27

13

1.051 1.051 1.229 1.229 1.129 1.399 .2 .2 1,210 950 1,210 950 1,450 1,450 27 32

.21

101.1

37.5 15 1 12 28.5 7.1

8

TABLE 2.—Composition cf experimental diets 14

.08

101.1

25.5 2.5 0

151

.15

101.1

0 0 28

16

17

.10

101.1

17 14 0 14 49 7.1

.02

101.1

27 1 0

18i

1.299 1.229 1.459 1.409 1.329 .2 .2 ,210 950 1,450 1,210 950 37 42

.15

101.1

24 15 0 13 42 7.1

Diets used in experiment 14 vs. unsupplemented diets of same protein and energy levels in Table 1. See Footnote 2, Table 1. 8 See Footnote 3, Table 1. , , . - , , ,- . , - „. * Basal diets used in experiments to determine optimal levels of amino acids and creatine hydrate did not contain these added levels of creatine hydrate or DL-methionine, but as indicated in individual experiments.

1 2

101.1

1,450

.30 Added DL-methionine %x Total cystine plus methionine (calculated) % 4 Creatine Hydrate Productive energy!$ 1,450 Protein %

Total

energy/ft

10 0 22

1

TABLE 1.—Composition of diets for experiment 3

Diets used in experiment 14 vs. supplemented diets of the same energy and protein levels in Table 2. Protein mixture contained one part fish meal, one part gelatin, and three parts of crude casein. Grams of constant ingredients per kilogram of diet: Salts V, 60; vit. mix, 2.5; vit. E oil 10 mg./gm. 0.6; feeding oil (300D-1,500A), 5; choline chloride, 2; procaine penicillin G 4 gm./#, .71. Vitamin mixture per kilogram of feed contained in mg. Biotin, 0.2; Menadione, 0.5; Pyridoxine, 4.0; Riboflavin, 6.0; Ca pantothenate, 20.0; Niacin, 50.0; Inositol, 1,000.0; Thiamine HC1, 6.0; Folic Acid, 2.0; Vit. B12, 0.015; and Sucrose to make up to 2.5 grams. The composition of Salts V was as follows with ingredients expressed in grams: CaC0 3 , 2,400; CaHP04-2H 2 0, 2,076; K2HPO4, 2,580; NaCl, 1,340; MgSCU- 7H 2 0, 816; Ferric citrate 6H2O, 220; CuS0 4 -5H 2 0, 2.4; ZnCh, 2.0; Kl, 6.4; MnS04-2H 2 0, 63.2.

1 2 3

Productive Protein %

Total

Ground yellow corn Cerelose Alphacel White grease Protein mixture 2 Constant ingredients 3

1

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1270

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHJEM

percent protein as the possible protein level for optimum growth at 1,210 Calories. At the 950 Calorie level, the best growth obtained was with 27 percent protein. These results gave the following optimum ratios: Calories/lb.

Protein %

950 1,210 1,450

27 29 32

C

^ [ ^

35.2 41.7 45.3

Hill and Dansky (1954) indicated that feed consumption was determined primarily by the energy level of the ration or the energy intake. Protein level had little or no effect on rate of feed consumption. Williams and Grau (1956) and Griminger et al. (1957), thinking along this same line, were able to show increased

FIG. 2. Feed conversion (gms. feed per gm. gain) of groups fed different energy and protein levels. Experiment 3.

growth in amino acid deficient diets by increasing feed consumption through lowering the energy content of the diets. They felt that the chicks would consume feed according to their energy need; and with less energy in the diet more feed would be consumed to make up this energy need. Donaldson et al. (1956) indicated that chicks appeared to consume relatively more energy in an effort to obtain other nutrients (presumably certain amino acids). Results of feed conversion are shown in Figure 2. Poorest feed conversion was on the diet with 17 percent protein at 1,450 Calories productive energy per pound. The birds on this diet were consuming excess feed to try to make up the protein deficiency of the diet, since with 1,450 Calories energy should not be the limiting factor. As the protein levels in the 1,450 Calorie diets increased, the feed conversion improved. The best feed

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The optimum ratio for chick growth increased as the energy increased and was not a constant ratio. This was contrary to the constant ratio of 42 as reported by Combs et al. (1955). These differences might be due to the difference in the sources of protein and fat used in the two sets of experiments. Further observations indicated symptoms of protein deficiency in the birds fed the diets with low protein levels and high energy. The birds fed the 1,450 Calorie diet with 17 percent protein showed poor feathering, excessive feather picking with consumption of the feathers picked, slow growth and excessive craving for some missing nutrients. At the end of the nine week experiment the birds had bare backs, necks, and breasts. These symptoms gradually diminished as the protein level at the 1,450 Calorie diets was raised until finally they disappeared at the 32 percent protein level in the high energy diet. It also appeared that at all three energy levels, 17 percent protein was inadequate. On the other hand excessive protein in the diets also depressed growth at all energy levels.

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

^ 1450 Calories v 1210 Calories ^

22

27 32 % Protein

950 Calories

37

42

FIG. 3. Average visceral fat (gms. per kg. live weight) in 9-week-old chickens. Experiment 3.

conversion figures occurred at 27 to 42 percent protein. At 1,210 Calories of productive energy per pound of feed, feed conversion of the birds showed improvement as the crude protein level increased from 17 percent to 22 percent of the diet, then remained constant throughout the remaining higher levels of protein. Feed conversion for birds on the 950 Calorie diets was comparatively poor throughout all protein levels at a fairly constant rate, indicating the need for more energy. Feed consumption was determined by both the energy need and the protein need of the birds. At the conclusion of the feeding trial, the birds were New York dressed. They were split open along the backbone and all the visceral fat was taken out and weighed. Figure 3 shows visceral fat in grams per kilogram of live weight of birds

fed the experimental diets. The graph shows that the 1,450 Calorie diets produced a high degree of fat deposition at all protein levels including the protein level that gave optimum growth at that energy level. Birds on 1,210 Calories of productive energy had high fat deposition at the low protein level of 17 percent, then the fat deposition dropped rapidly as the protein level increased. Birds on the 950 Calorie diets had low fat deposition throughout all protein levels. This was contrary to the report of Donaldson et al. (1956) that changes in Calorie-protein ratio of the diet had marked effects on the body composition of chicks, and that wider C/P ratios increased the fat and gross energy content of the whole carcass. The visceral fat deposition in this experiment did not follow the C/P ratio completely. Visceral fat deposition was affected more by the source and amount of energy. This can be seen in Table 3. At a C/P ratio of approximately 55, the birds differed greatly in their fat deposition. Addition of 8 percent white grease to the diet doubled the fat deposition in the birds. A further increase in fat to 22 percent of the diet resulted in a further increase of fat deposition in the birds. These

TABLE 3.—Visceral depot fat at approximately the same dietary C/P ratio (Experiment 3) 1

Dietary protein

Added white grease

Productive energy per pound of feed

C/P ratio

Visceral depot fat per kilo live weight

% 17 22 27

% 0 8 22

Cal. 950 1,210 1,450

55.9 55.0 53.7

gms. 6.3 13.6 16.5

22 27 32

0 8 22

950 1,210 1,450

43.2 44.8 45.3

5.4 10.8 18.5

1 Straight-run New HampshireXS.C. White Leghorn crossbreds, 9 weeks.

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17

^

1271

1272

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHJEM

However, many workers (Almquist, 1949; Almquist and Merritt, 1950; Grau, 1948; Grau and Kamei, 1950; Griminger et al., 1956), found that as dietary protein level increased, requirement for some of the essential amino acids (methionine plus cystine, arginine, lysine, and tryptophan) also increased. With high fat diets, another variable has been introduced to this problem. Therefore the objective of the following experiments was to study the effect of amino acid supplementations in relationship to the energy and protein of the diets. Experiments 6, 8, 9, 11, 13 and 14. These experiments were concluded at five weeks, seven weeks or eight weeks of age and were conducted with day-old Arbor Acre White Rock male chicks. The diets are shown in Tables 1 and 2. Calculation of the amino acid content of the diets is based on tables taken from the National Research Council (1954), Ewing (1947), Almquist (1952) and from Block and Boiling (1947). In order to take into account the feed efficiency as well as growth rate, an index

was obtained for each experimental diet by dividing the average weight gained by the feed conversion figure (Bird, 1955). Tentative amino acid requirements were calculated for the 20, 27, and 32 percent protein diets on the assumption that these requirements would exceed the N.R.C. figures in the same proportion as the respective dietary protein levels exceeded 20 percent. As an example: the N.R.C. requirement for methionine plus cystine at the 20 percent protein level is .80 percent; therefore the proportionate requirement of the sulfur amino acids at the 22 percent protein level is:

Calculated by this method, arginine, methionine plus cystine, and tryptophan were deficient in the experimental diets. On the other hand it is possible that the requirements for essential amino acids may be governed by the balance of the amino acids regardless of the amount in percent. Therefore the calculations given below are based on amino acid ratio using methionine plus cystine as one and all the other essential amino acids as a ratio to it: N.R.C. requirement for methionine plus cystine at 20 percent protein is 0.80 percent and for arginine is 1.2 percent. Therefore the ratio for arginine requirement would be: 0.80

1 =— X= 1.5 arginine ratio. 1.20 X Calculations for the experimental diet with 22 percent protein are as follows: Experimental diet with no methionine supplementation contained 0.70 percent methionine plus cystine and 1.15 per cent arginine. Therefore,

the ratio of arginine to methionine plus cystine in the experimental diet. Com-

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results were repeated with birds fed diets with a C/P ratio of approximately 45. It is apparent that birds receiving higher levels of fat were able to deposit greater quantities of fat in their carcasses at the same C/P ratio. Results of the above experiment showed that increasing the productive energy of the diets called for an increase in the protein. This increase need of protein can be the result of the need for protein as a whole or possibly a reflection of the need for some amino acids that are deficient. Baldini and Rosenberg (1955) showed that increasing the dietary energy level increased the methionine requirement of chicks. Almquist (1957) stated that, when a protein is only slightly deficient in an amino acid, it is sometimes possible to meet the needs of the animal for the amino acid by simply feeding a higher percentage of the protein.

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

Outline and results of experiment 6 are given in Table 5. The basal diet used contained 22 percent protein with 1,210 Calories of productive energy per pound of feed and was supplemented with 0.35 percent DL-methionine. The supplements of arginine, tryptophan and threonine were calculated to bring the dietary levels up to the required ratios to methionine plus cystine. Experimental diets were fed to duplicate pens. This experiment was terminated at the end of seven weeks. Arginine supplementation improved both gain and feed conversion, indicating that the basal diet was deficient in arginine as calculated. Further supplementation with 0.084 percent DL-tryptophan in combination with arginine showed a slight growth depression. No improvement was noted with DL-tryptophan addition to the basal diet indicating the amount in the diet was adequate. The experiments of Griminger et al. (1956) concluded that in a 28 percent protein diet, 0.17 percent tryptophan was adequate and this experimental diet contained 0.20 percent calculated trypto-

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pared to the 1.5 arginine requirement ratio this diet is adequate in arginine with no methionine supplementation. Calculations of the amino acid ratios within the three basal diets with and without methionine supplementation are shown in Table 4 with the N.R.C. requirement ratios for comparison. The three basal diets without methionine supplementation showed adequate ratios of all the other essential amino acids even though the levels were inadequate in some cases according to the N.R.C. This means that in the basal diets, the first limiting amino acid was methionine or methionine plus cystine. Upon supplementation of the experimental diets with methionine, the ratios indicated deficiency in arginine, tryptophan, threonine and possibly phenylalanine. The next experiments were designed to test and to correct, if necessary, these deficiencies.

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1274

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHJEM TABLE 5.—Outline and summary of experiment 6l Feed

Feed Supplements

Av. wt. by diets

Av. wt. gain

gain by diets

Index of3 performance

1.83

571

1.64 1.64

1,216

1.64

716

1,151 1,191

1.63 1.68

1,171

1.66

682

B a s a l + . 4 5 % A r g . HC1 ) +. 084% DL Tryptophan 1 + .274% DL Alio Free f Threonine J

1,221 1,242

1.64 1.56

1,230

1.60

742

Basal+,084%1 DL Tryptophan/

1,091 1,125

1.76 1.77

1,108

1.77

603

grams 1,057 1,120

1.92 1.73

Basal+,45%1 Arginine HC1J

1,206 1,227

B a s a l + . 4 5 % A r g . HC1 1 + . 084% DL Tryptophan/

1 2 3

White Rock males, 7 weeks. Basal=22% protein 1,210 Cal./# plus .35% DL-Methionine. Index of performance = Av. wt. divided by Feed/Gain.

phan. The best result observed was with a combination of all three amino acids, but this result was only a little better than that obtained with arginine alone. Therefore, arginine was the most limiting amino acid in the methionine supplemented diet. This may be due to the unavailability of the arginine from the casein for Arnold et al. (1936) and Klose et al. (1938) showed that part of the arginine in casein was unavailable to chicks. On the other hand Almquist et al. (1941) and Wietlake etal. (1954) reported that a casein diet supplemented with gelatin as a source of arginine was adequate. The basal diet used contained gelatin. Outline and results of experiment 8 are given in Table 6. Basal diets of 22 and 32 percent protein were supplemented with L-arginine HC1 and DL-phenylalanine to bring the diets up to the required ratios. This experiment showed increased requirement for methionine plus cystine as the protein level increased but at a slower rate. The sulfur amino acid requirement

also increased with the increase of productive energy of the diets. Optimum level of methionine plus cystine was not more than 0.68 percent for the 22 percent protein diet at 700 Calories per pound productive energy. This optimum level of sulfur amino acids increased to 0.93 perTABLE 6.—Outline and summary of experiment 8l Percent 2 protein

Calories per pound

Total methionine plus cystine

Av. weight

Feed conv.

Index of performance

22 22 22 22

700 700 700 700

%

.68 .83 .93 1.03

gms. 933 795 . 917 691

2.79 3.18 2.75 3.01

320 238 319 217

32 32 32 32

700 700 700 700

.98 1.13 1.23 1.33

878 841 962 847

2.75 2.88 2.79 2.90

305 252 330 252

22 22 22 22

1,210 1,210 1,210 1,210

.68 .83 .93 1.03

1,253 1,423 1,407 1,392

1.81 1.69 1.63 1.70

672 820 840 736

32 32 32 32

1,210 1,210 1,210 1,210

.98 1.13 1.23 1.33

1,319 1,523 1,421 1,471

1.59 1.55 1.58 1.50

807 955 812 957

1 White Rock males, 8 weeks. 2 All diets contain added 0.57% L-arginine HC1 plus 0.46% DL-phenylalanine.

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grams 1,088

Basal2 Basal

1275

P R O T E I N , AMINO ACIDS AND E N E R G Y RELATIONSHIPS

TABLE 7.—Outline and summary of experiment 9lfi Added DL-meth.

%

.35 .35 .35 .35 .35 .35

0 0 .35 0 1 2

Added Total cystine plus meth. L-Arg. HC1

%

1.03 1.03 1.03 1.03 1.03 1.03 .68 .68 1.03 .68

% 0 0 0 0 .46 .46 .46 0 0 0

Total arg.

%

1.15 1.15 1.15 1.15 1.53 1.53 1.53 1.15 1.15 1.15

Added creatine

0

% .15 .29 .58

0 .29 0 .29 .29 0

Av. wt.

Feed conv.

Index of performance

grams 654 753 692 702 737 700 570 640 706 641

1.58 1.48 1.52 1.50 1.48 1.46 1.73 1.64 1.50 1.66

391 484 430 441 471 450 305 364 443 361

cent for the 22 percent protein diet at 1,210 birds at 753 grams. Addition of all three (0.35 percent DL-methionine, 0.46 percent Calories per pound. Experiment 9 was designed to test the L-arginine HC1 and 0.29 percent creatine possibility of utilizing creatine hydrate in hydrate) did not show any further implace of L-arginine HC1 as a supplement provement in the average weight of the birds. Increasing the added level of for the arginine deficient diets. Wietlake et al. (1954) showed a large creatine hydrate from 0.15 percent to 0.29 improvement in chick growth when a syn- and 0.58 percent with 0.35 percent DLthetic diet with 35 percent casein and 0.5 methionine did not give further improvepercent methionine was supplemented ment in chick growth over that obtained with 1.5 percent creatine. Earlier Alm- with 0.15 percent creatine hydrate. Creaquist et al. (1941) found that 1.5 percent tine hydrate was an effective substitute for creatine was equal to one percent glycine L-arginine HC1 in combination with DLand one percent arginine for increasing methionine. growth of chicks on a casein diet. Experiments 10 and 11 (Tables 8 and Results in Table 7 showed that when the 9) further explored the methionine re22 percent protein diet with 1,210 Calories quirement at different protein and energy per pound was supplemented singly with levels using creatine hydrate in accordance only 0.35 percent DL-methionine, 0.29 per- with the findings of the previous expericent creatine hydrate, or with no supple- ment in place of L-arginine HC1. At 32 mentation, the average weights of the percent protein, the optimum level of birds were approximately the same, indi- methionine plus cystine increased from cating no response from methionine alone 1.13 percent at 700 Calories productive or creatine hydrate alone. Adding 0.35 energy per pound to 1.23 percent as the percent DL-methionine plus 0.46 percent productive energy of the diet increased to L-arginine HC1 gave approximately 950 Calories. At energy levels of 1,210 and maximal growth with an average chick 1,450 Calories the optimum levels of weight of 737 grams. Supplementation methionine plus cystine stayed at the same of the diet with 0.15 percent creatine level of 1.23 percent. hydrate and 0.35 percent DL-methionine Experiment 11 was concluded at the resulted in the best average weight of end of the fifth week since on review of

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White Rock Males, 5 weeks. Basal diet contained 22% protein and 1,210 Cal./pound.

1276

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHTEM TABLE 8.—Outline and summary of

experiment 10l*

Cal. per pound

Added BL-

meth.

0

950 950 950 950

0

1,210 1,210 1,210 1,210

0

1,450 1,450 1,450 1,450

0

Av. weight

Feed Index of conver- performsion ance

%

%

.15 .25 .35

.98 1.13 1.23 1.33

grams 807 843 861 833

2.83 2.83 2.99 2.96

270 282 274 267

.15 .25 .35

.98 1.13 1.23 1.33

1,294 1,262 1,311 1,248

2.13 2.00 1.98 2.03

586 610 638 592

.15 .25 .35

.98 1.13 1.23 1.33

1,322 1,513 1,525 1,424

1.69 1.68 1.58 1.60

756 877 940 865

.15 .25 .35

.98 1.13 1.23 1.33

1,439 1,397 1,494 1,451

1.57 1.46 1.45 1.43

894 927 1,004 990

1 White Rock males, 8 weeks. 2 All diets contained 32% protein, 1.61% arginine, and 0.15% added creatine hydrate.

the previous experiments it was noted that by the fifth week whatever influence the amino acid supplements exerted would be carried through to the eighth week. At 1,450 Calories of productive energy, as the protein levels of the experimental diets increased the optimum level of the sulfur amino acids increased but at a slower rate. Optimum levels of methionine plus cystine for chick growth at 1,450 Calories productive energy were: Protein, % Methionine plus cystine requirement: as determined, % as estimated from protein level, %

The values determined by chick test compared favorably with those estimated from protein levels, at protein levels from 17 to 27 percent. As protein level increased above 27 percent, the requirement for methionine plus cystine increased but did not keep pace with the protein level. Results of this and previous experiments showing the total methionine plus cystine for optimum chick growth at various protein and energy levels are summarized in Table 10. At each energy

At the end of the feeding trial of ex17

22

27

0.683 0.832 1.091 0.68 0.88 1.08

37

42

1.399 1.67

1.459 1.89

periment 13 two birds with live weights closest to the average weight of each group were selected for carcass analysis. The birds were killed by dislocating the neck, wrapped and frozen at zero degrees Fahrenheit. Birds were kept frozen until they were analyzed, at which time they were partially thawed and cut into chunks large enough to fit into a one-half horse power Hobart meat grinder. The cut-up birds were again frozen and the feathers were cut into smaller sizes for convenience

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700 700 700 700

Total meth. and cystine in diet

level, the optimum level of the sulfur amino acids increased with increase in protein level of the diets but at a slower rate. Also only at the higher protein levels of 27, 32, 37 and 42 percent was there any increase of the sulfur amino acid level for optimum chick growth with increase in the energy level. Creatine hydrate and appropriate levels of methionine were added at various protein and energy levels in the further study of the relationship of energy to protein with a "balanced" protein. There is no assurance that ideal balance was achieved, but certainly the supplementation with methionine and creatine hydrate achieved a better balance than that which prevailed in the diets used in experiment 3. Diets used in experiment 13 are given in Table 2. This experiment was similar to experiment 3 in that there were three energy levels of 950,1,210 and 1,450 Calories of productive energy per pound and each energy level contained diets with 17, 22, 27, 32, 37 and 42 percent crude protein. The experiment was concluded at the end of eight weeks. Carcasses of the birds were analyzed for protein, moisture and ether extract.

PROTEIN, AMINO ACIDS AND ENERGY

1277

RELATIONSHIPS

TABLE 9.—Outline and summary of experiment IP-* Methionine +cystine in diet

%

%

17 17 17 17

.53 .53 .53 .53

0

22 22 22 22

.68 .68 .68 .68

0

27 27 27 27

.84 .84 .84 .84

0

37 37 37 37

1.15 1.15 1.15 1.15

0

42 42 42 42

1.31 1.31 1.31 1.31

0

1 2

Index of performance

Av. weight

Feed conversion

grams 414 485 457 439

1.77 1.74 1.71 1.60

211 256 245 249

1.10 1.10 1.10 1.10

514 593 534 581

1.63 1.38 1.61 1.46

290 400 308 370

.84 .99 1.09 1.19

1.37 1.37 1.37 1.37

610 620 632 631

1.51 1.36 1.34 1.29

329 427 439 460

.15 .25 .35

1.15 1.30 1.40 1.50

1.89 1.89 1.89 1.89

610 651 737 693

1.29 1.32 1.22 1.23

443 464 569 531

.15 .25 .35

1.31 1.46 1.56 1.66

2.17 2.17 2.17 2.17

637 686 663 668

1.31 1.23 1.22 1.25

456 527 509 504

Added DL-meth.

Total meth. +cystine

Arg. in diet

%

%

%

.15 .25 .35

.53 .68 .78 .88

.85 .85 .85 .85

.15 .25 .35

.68 .83 .93 1.03

.15 .25 .35

White Rock males, 5 weeks. All diets contained 1,450 Calories of productive energy per pound and 0.2% of added creatine hydrate.

in grinding. Then the cut-up carcasses, including bones, head, feet, viscera and feathers were ground in the Hobart grinder, and dried in a forced-draft dryer at approximately 90° Centigrade for 24 hours, and then reground in a Wiley mill. A sample of each individual chicken was taken from this grinding and used for final moisture determination, Kjeldahl, and

ether extract. Ether extracts were done in a Goldfish apparatus with ether as the extracting solvent for eight hours per sample. Results and outline of experiment 13 are given in Table 11. The growth response curves of experiment 13 are shown in Figure 4. The diets with 22 percent protein and 950 Calories of productive

TABLE 10.—Suggested total methionine and cystine levels for optimum growth at various protein and energy levels

Protein

%

17 22 27 32 37 42

Methionine plus Methionine plus cystine requirement by chick cystine require- Methionine plus test at energy levels of: ment calculated cystine in basal from protein level 950 Cal./pound 1,210 Cal./pound 1,450 Cal./pound

%

.6 .88 1.08 1.28 1.48 1.68

%

.53 .68 .84 .99 1.15 1.31

%

.83 .93 1.05 1.13 1.23 1.33

%

.83 .93 1.05 1.23 1.30 1.40

%

.83 .93 1.19 1.23 1.40 1.46

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Protein

1278

K. C. LEONG, M. L. SUNDE, H. R. BIRD AND C. A. ELVEHJEM TABLE 11.—Outline and summary of 12

experiment 13 '

Feed Index of conver- performsion ance

Added Dlmethionine

Av. weight

17 17 17

1,450 1,210 950

.30 .30 .30

%

grams 888 1,155 1,254

2.02 2.14 2.17

420 522 559

22 22 22

1,450 1,210 950

.25 .25 .25

1,219 1,486 1,298

1.67 1.62 2.06

703 890 612

27 27 27

1,450 1,210 950

.35 .21 .21

1,413 1,488 1,308

1.54 1.68 1.95

890 862 649

32 32 32

1,450 1,210 950

.24 .24 .14

1,419 1,414 1,289

1.45 1.66 1.91

948 826 654

37 37 37

1,450 1,210 950

.25 .15 .08

1,497 1,405 1,217

1.40 1.60 2.10

1,038 855 560

42 42 42

1,450 1,210 950

.15 .10 .02

1,351 1,322 1,232

1.48 1.61 1.99

885 795 599

22 37

950 1,450

.25 .25

1,304 1,331

2.16 1.43

584 900

%

1 2

White Rock males, 8 weeks. All diets supplemented with 0.2% creatine hydrate.

energy and with 37 percent protein and 1,450 Calories were each fed to duplicate groups. The duplicate groups fed the latter Gram > diet differed appreciably from each other, and the average weight of each group is shown by a dot and circle in Figure 4. If the average of the duplicates is taken as the true value, the optimum growth response for 1,450 Calories of productive energy was obtained with 27 percent protein. With 1,210 Calories of productive energy the break for optimum growth occurred at 22 percent protein. At 950 Calories of productive energy the break for optimum growth is somewhere off the chart below 17 percent protein or may be approximately 17 percent. This would then give C/P ratios of 53.7, 55.0 and 55.7 for 1,450, 1,210 and 950 Calories of productive energy, respectively, for optimum chick growth. Therefore, the optimum C/P ratios for the three energy levels were 'l7 22 27 32 37 42 approximately the same. Experiment 13 % Protein was similar to experiment 3 in that as the productive energy increased the require- FIG. 4. Average weights of 8-week-old groups fed different energy and protein levels. Experiment 13.

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Cal./lb.

Protein

ment for protein increased. Aside from this, the experimental results differed in many points. The growth response curves of experiment 13 rose sharply to the optimum growth for each energy level and then flattened out with no sharp peaks. Another difference was that the protein requirement for each energy level was lower in experiment 13 than in experiment 3. At 950, 1,210 and 1,450 Calories of productive energy, the optimum protein levels were 27, 29 and 32 percent respectively in experiment 3, as compared to 17, 22, and 27 percent protein levels respectively at the same energy levels for experiment 13. This lower requirement for the balanced protein probably means that a larger proportion of the balanced than of the unbalanced protein was used as protein. With lowered protein requirements the optimum C/P ratio for experiment 13 was 55 as compared to ap-

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

1279

The data thus far presented indicated that balancing the diet with amino acids had a definite effect on the growth response curves, C/P ratios, and the protein requirements for optimum chick growth. The earlier experiment 3 with unsupplemented diets was conducted with straightrun New Hampshire X Single Comb White Leghorn crossbred chicks. The later experiments using supplemented diets were with White Rock male chicks. Therefore, it was desirable to feed in one experiment, using one breed of chicken, the supplemented and unsupplemented experimental diets to see if the results obtained were in agreement with the results obtained under conditions which varied with respect to breed, sex, and time of the year. This was done in experiment 14. This experiment contained one productive energy level of 950 Calories at the six levels of protein (17, 22, 27, 32, 37 and 42 percent). Comparison was made between the diets used in experiment 3 and diets

27 32 % Protein

FIG. 5. Average weights of groups fed with and without supplements of DL-methionine and creatine hydrate. Experiment 14.

of the same energy and protein levels used in experiment 13 supplemented with creatine hydrate and DL-methionine. The growth response curves are shown in Figure 5. This experiment confirmed the comparisons made between the previous experiments, indicating that the conclusions drawn were applicable and the variations in breed, sex, and time of the year were not critical. The original unsupplemented diet gave a very sharp peak at 27 percent protein. On the other hand, balancing the protein with DL-methionine and creatine hydrate tended to flatten the growth response curve. It started out at 1,240 grams average weight at 17 percent protein, reached a peak at 1,332 grams with 22 percent protein in the diet and

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proximately 31.8, 35.2, and 37.8 for productive energy levels of 950, 1,210 and 1,450 Calories respectively in experiment 3. Also as a result of balancing the protein, there were no signs of severe protein deficiency in experiment 13 such as were observed in experiment 3. Chicks in experiment 3 fed the diet containing 17 percent protein with 1,450 Calories of productive energy per pound developed severe protein deficiency as indicated by poor growth, poor feathering, feather picking and feather eating. These symptoms continued at a declining rate in birds fed the 1,450 Calorie diets with 22 and 27 percent protein until they disappeared with 32 percent protein in the diet. The only symptom observed with the same 1,450 Calorie diets balanced with DL-methionine and creatine hydrate was some depression in growth at the lower protein levels.

1280

K. C. L E O N G , M. L. SUNDE, H. R. BIRD A N D C. A. E L V E H J E M

TABLE 12.—Results of analysis of carcasses from birds of experiment 13 Carcass analysis Protein % in diet

Cal./lb.

Ratio Cal./prot.

Ether extract % protein

% moisture

%

wet basis

dry wt. basis

1,450 1,210 950

85.3 77.2 55.9

16.89 17.13 19.16

62.17 62.66 66.76

16.55 14.95 8.64

43.82 40.04 25.90

22 22 22*

1,450 1,210 950

65.9 55.0 43.2

19.18 18.60 19.98

65.11 63.55 67.19

11.45 10.87 8.83

32.82 31.59 26.83

27 27 27

1,450 1,210 950

53.7 44.8 35.2

19.01 19.66 20.56

65.08 64.78 67.79

11.32 10.94 6.29

32.55 31.05 19.51

32 32 32

1,450 1,210 950

45.3 37.8 29.7

18.86 20.02 20.55

61.81 67.74 69.06

15.20 8.17 4.26

39.74 25.32 13.78

37* 37 37

1,450 1,210 950

39.2 32.7 25.7

19.98 19.21 19.30

66.08 66.94 69.84

8.93 8.59 5.18

26.38 25.75 17.10

42 42 42

1,450 1,210 950

34.5 28.8 22.6

19.51 19.96 19.80

64.22 66.08 71.17

11.85 10.48 3.84

33.11 30.82 12.43

* Average of duplicate groups.

dropped gradually to 1,284 grams at 42 percent protein. This experiment again showed that less protein was required for optimum growth at each energy level with the better balanced protein diet. In this experiment and in experiment 3, the unsupplemented 950 Calorie diet needed 27 percent protein for optimum chick growth as compared to 22 percent protein in experiment 14 or possibly 17 percent protein in experiment 13 when the diet was supplemented with DL-methionine and creatine hydrate. Table 12 summarizes the results of analyses of the carcasses of birds from experiment 13. At any protein level, as the energy increased the ether extract content of the carcasses also increased. In turn, as the fat level increased the percent of moisture in the carcasses decreased. Only in the groups fed the 17 percent protein

diets did the energy level of the diets appear to affect the protein content of the carcasses. With protein levels of 22, 27 and 32 percent in the diets, the resulting carcass proteins were affected much less by variation of dietary energy. There apparently were no differences in carcass protein due to dietary energy changes at the two highest dietary protein levels. As in experiment 3, the birds fed diets with 1,450 Calories productive energy, regardless of protein levels or C/P ratio, had a higher percentage of ether extract than did birds fed the 1,210 or 950 Calorie diets. In turn, more ether extract was found in birds fed diets with 1,210 Calories than in those fed diets with 950 Calories. The source or amount of energy rather than the C/P ratio affected the ether extract of the carcasses. This is clearly shown in Table

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17 17 17

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

1281

TABLE 13.—Ether extract of birds fed diets with approximately equal C/P ratios {experiment 13) Grams

Dietary protein

Added white grease

Dietary productive energy

%

%

Cal./lb. 950 1,210 1,450

55.9 55.0 53.7

950 1,210 1,450

43.2 44.8 45.3

17 22 27 22 27 32

0 11.5 26.0 0 12.0 26.0

Ether extract C/P ratio of carcass, wet basis

3

'

M 0

%

8.64 10.87 11.32 8.83 10.94 15.20

— 1450 Calories X12I0 Calorics

&

A

A 950 Calories

2.400 •

\

\ ^

\

\

2.100

^ \

\

1.800

\^

>v

^ v

1.500

N.

\

1. 200 I 17

, 22

(

f

X

_

27 32 % Protein

^~^-A 37

42

FIG. 6. Grams live weight per gram dietary protein as influenced by energy and protein levels. Experiment 13.

most efficient level was 1,210 Calories, and the 1,450 Calorie diets were the least efficient in terms of conversion of dietary energy to live weight. Figure 8 shows that the higher the energy level the greater the amount of carcass fat produced per kilogram of feed. Only at the lower energy level of 950 Calories did the protein level exert some influence on the carcass fat level per kilogram of feed. As the protein level increased the carcass fat level declined. This suggests that more feed was consumed by the chickens in trying to obtain sufficient protein and the resulting excess energy was deposited in the broilers as body fat. Figure 9 illustrates the grams of carcass protein per kilogram of feed. Although it appeared that high levels of protein in the diets (32, 42 and 37 percent protein at the 950, 1,210 and 1,450 Calorie levels,

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Figure 7 shows, as would be expected, that the most efficient use of Calories was at the lowest level, 950 Calories. Next

. K

3.000 N .

2.700 \

13 comparing diets of similar C/P ratio differing in the amount and source of energy. With C/P ratios approximating 55, the birds differed greatly in their ether extract content. The percentage of ether extract increased each time the dietary level of white grease was increased. This trend was repeated with the birds fed diets having C/P ratios of approximately 45. These results indicated that the dietary fat was stored as fat more readily than were other sources of energy. Figure 6 shows the efficiency of conversion of dietary protein to live weight. It points out that at each protein level the protein was utilized better at the higher energy levels. Apparently adequate energy was required in order for the protein to exert a greater influence on growth. It was also observed that, regardless of energy levels, as the protein level increased the grams of live weight obtained per gram of feed protein decreased. At any energy level as the protein level was increased from 17 percent to 42 percent the grams of live weight per gram of feed protein dropped at approximately a 45 degree slope. All three energy levels displayed this characteristic except for a slight break at 1,210 Calories and 22 percent protein.

. *

1282

K. C. LEONG, M. L. STTNDE, H. R. BIRD AND C. A. ELVEHJEM

FIG. 7. Grams live weight per therm as influenced by energy and protein levels. Experiment 13.

Protein

FIG. 8. Grams carcass fat per kilogram of feed as influenced by dietary energy and protein. Experiment 13.

respectively), were required to obtain optimum carcass protein per kilogram of feed, the energy requirement also must be considered. The highest amount of carcass protein per kilogram of feed was with 1,450 Calorie diets, next highest was with 1,210 Calorie diets and the lowest with 950 Calorie diets. In general, as the energy level increased from 950 to 1,210 and then 1,450 Calories the grams of carcass protein per kilogram of feed also increased. This demonstrates the role of adequate energy in allowing a larger portion of dietary protein to act as protein. Figure 10 illustrates the gain in grams per kilogram of feed. As would be expected, the most economical use of the FIG. 9. Grams carcass protein per kilogram of feed as influenced by dietary energy and protein. Experiment 13.

27 %

3Z Protein

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ft

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

1283

cent protein diets, as compared to the feed conversion figures at the other protein levels, appeared to be impaired. The birds apparently over-consumed feed to compensate for sub-optimal protein with a resulting increase in body fat content. This appeared to be the case with all three energy levels till high enough protein levels were reached at 32, 37 and 37 percent protein at 950, 1,210 and 1,450 Calories, respectively. SUMMARY

FIG. 10. Gain in live weight per kilogram of feed as influenced by dietary energy and protein. Experiment 13.

feed was at the highest energy level of 1,450 Calories with 1,210 Calorie diets following second in efficiency and the least economical in this experiment being the 950 Calorie diets. The most efficient gain at each energy level was not at the optimum C/P ratio for chick growth. Optimum use of feed at 1,450 Calories was with 37 percent protein. For 1,210 Calories again it was with 37 percent protein while at 950 Calories it was with 32 percent protein as compared to 27, 22 and 17 percent protein as the optimum levels for chick growth, respectively. This might be because the birds at the optimum C/P ratio for growth were able to consume extra feed to make up the slight protein deficiency to obtain the optimum growths. The feed conversion figures for the 17 per-

The protein requirement for optimum chick growth at energy levels of 950, 1,210 and 1,450 Calories and with diets balanced with DL-methionine and creatine hydrate dropped to 17, 22, and 27 percent respectively. This indicated that a greater portion of the "balanced" protein was utilized as protein for growth. The protein properly supplemented with amino acids permitted a wider and more nearly constant C/P ratio than a poorer unsupplemented protein. With DL-methionine and

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% Proteiir:

Using diets with a protein mixture of one part each of fish meal and gelatin and three parts of crude casein and energy levels of 950, 1,210 and 1,450 Calories productive energy per pound, it was shown that as the energy level of the diets increased the percentage of protein required for optimum growth of chicks also increased. This was true for diets supplemented or unsupplemented with methionine and creatine hydrate. Protein levels for optimum growth with the unsupplemented diets at 950, 1,210, and 1,450 Calories were 27, 29, and 32 percent respectively. These would correspond to optimum Calorie to Protein ratios (C/P) of 35.2, 41.7, and 45.3. This indicated a rising C/P ratio with increasing energy level in the diets. Birds on the highest energy diets with low protein developed severe protein deficiency.

1284

K. C. LEONG, M. L. SUNDE, H.:. R. BIRD AND C. A. ELVEHJEM

ACKNOWLEDGMENTS

DL-Methionine for these experiments was furnished by E. I. DuPont de Nemours and Co., creatine hydrate by Allied Chemical and Dye Corporation, and several of the vitamins by Merck Sharp & Dohme Research Laboratories. REFERENCES Almquist, H. J., 1949. Amino acid balance at supernormal dietary levels of protein. Proc. Soc. Exp. Biol. Med. 72: 179-180. Almquist, H. J., 1952, 1957. Proteins and Amino Acids in Animal Nutrition. 2nd and 3rd editions. Division National Distillers and Chemical Co. V. S. Industrial Chemicals Co.

Almquist, H. J., and J. B. Merritt, 1950. Protein and arginine levels in chick diets. Proc. Soc. Exp. Biol. Med. 73: 136. Almquist, H. J., E. Mecchi and F. H. Kratzer, 1941. Creatine formation in the chicks. J. Biol. Chem. 141: 365-373. Arnold, A., O. L. Kline, C. A. Elvehjem and E. B. Hart, 1936. Further studies on the growth factor required by chicks. The essential nature of arginine. J. Biol. Chem. 116: 699-709. 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: 1301-1307. Bird, H. R., 1955. "Performance index" of growing chickens. Poultry Sci. 34: 1163-1164. Block, R. J., and D. Boiling, 1947. The Amino Acid Composition of Proteins and Foods. First edition. Second printing. Charles C Thomas, Publisher. Springfield, Illinois. Carver, D. S., and E. L. Johnson, 1953. Unidentified growth factors for the chick in vegetable oils and fatty acid concentrates. Poultry Sci. 32: 701-705. Combs, G. F., and G. L. Romoser, 1955. A new approach to poultry feed formulation. Maryland Agr. Exp. Sta. Misc. Pub. No. 226. Donaldson, W. E., G. F. Combs and G. L. Romoser, 1954. Results obtained with added fat in chick rations. Poultry Sci. 33: 1053. 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 chick. Poultry Sci. 35: 1100-1105. Donaldson, W. E., G. F. Combs, G. L. Romoser, W. C. Supplee and J. L. Nicholson, 1956. Fat tolerance in chickens. Poultry Sci. 35: 1140. Ewing, W. R., 1947. Poultry Nutrition. Third edition. W. Ray Ewing, South Pasadena, California. Fraps, G. S., 1946. Composition and productive energy of poultry feeds and rations. Texas Agr. Exp. Sta. Bulletin No. 678. Grau, C. R., 1948. Effect of protein level on the lysine requirement of the chick. J. Nutrition, 36: 99-108. Grau, C. R., and M. Kamei, 1950. Amino acid imbalance and the growth requirement for lysine and methionine. J. Nutrition, 41: 89—101. Griminger, P., H. M. Scott and R. M. Forbes, 1956. The effect of protein level on the tryptophan requirement of the growing chick. J. Nutrition, 59: 67-76. Griminger, P., H. M. Scott and R. M. Forbes, 1957. Dietary bulk and amino acid requirement. J. Nutrition, 62: 61-69.

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creatine hydrate, the optimum C/P ratio for chick growth was approximately 55. Poor feathering and feather picking were observed in the absence, but not in the presence of supplements of DL-methionine and creatine hydrate. The requirement for methionine plus cystine increased as the protein level of the diet increased. It also increased as dietary energy increased, if protein was adequate. Creatine hydrate was effective in replacing L-arginine HC1. Visceral fat deposition was influenced more by the source and amount of energy than by the C/P ratio. Birds fed the 1,450 Calorie diets had high visceral fat deposition regardless of protein levels. Birds on 1,210 Calorie diets had high fat deposition at the low protein level of 17 percent and lower fat deposition at protein levels of 22% or more. At 950 Calories, the birds had low fat deposition at all protein levels. Ether extract of the carcasses was influenced by the source and amount of energy rather than the C/P ratio. The content of ether extract was inversely correlated to the moisture content of the carcasses. At the lowest protein level, the protein content of the birds was correlated inversely with the ether extract.

PROTEIN, AMINO ACIDS AND ENERGY RELATIONSHIPS

38: 247-256. Robertson, E. I., R. F. Miller and G. F. Heuser, 1948. The relation of energy to fiber in chick rations. Poultry Sci. 27: 736. Runnels, T. D., 1954. The value of animal fat in combination with various other ingredients in broiler rations. Poultry Sci. 33: 1090. Scott, H. M., L. D. Matterson and E. P. Singsen, 1947. Nutritional factors influencing growth and efficiency of feed utilization. 1. The effect of the source of carbohydrate. Poultry Sci. 26: 554. Siedler, A. J., and B. S. Schweigert, 1953. Effect of feeding graded levels of fat with and without choline and antibiotic plus B12 supplement to chicks. Poultry Sci. 32: 449. Sunde, M. L., 1954. The use of animal fats in poultry feeds. J. American Oil Chem. Soc. 31: 49-52. Wietlake, A. W., A. G. Hogan, B. L. O'Dell and H. L. Kempster, 1954. Creatine formation in chick. J. Biol. Chem., 141: 365. Williams, M. A., and C. R. Grau, 1956. Food intake and utilization of lysine-deficient protein by the chick in relation to the digestible energy concentration of the diet. J. Nutrition, 59: 243-254. Yacowitz, H., 1953. Supplementation of corn-soybean oil meal rations with penicillin and various fats. Poultry Sci. 32: 930. Yacowitz, H., and V. D. Chamberlin, 1954. Further studies on the supplementation of broiler rations with fats. Poultry Sci. 33: 1090.

Relation of Arginine and Lysine to Feather Tyrosinase Activity1,2 W . J . OWINGS AND S. L .

BALLOTJN

Department of Poultry Husbandry, Iowa State University of Science and Technology, Ames (Received for publication April 1, 1959)

P

ROTEIN has a diversity of functions in animals; therefore, amino acid imbalances may display various types of symptoms. Some of these symptoms may 1 Journal Paper No. J-3613 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa. Project No. 1062. 2 A portion of the thesis presented by the senior author in partial fulfillment of the requirements for the M.S. degree.

be simply related to growth and efficiency of feed utilization, and some may be more subtle, such as differences in feather development or the well known bleaching or whitening of feathers as a result of lysine deficiency. Vohra and Kratzer (1957) reported that for both growth and feather pigmentation in poults, a single daily supplement of lysine was inferior to the same amount

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Henderson, E. W., and W. E. Irwin, 1940. The tolerance of growing chicks for soybean oil in their ration. Poultry Sci. 19: 389-395. Hill, F. W., and L. M. Dansky, 1954. Studies of the energy requirements of chickens. 1. The effect of dietary energy level on growth and feed consumption. Poultry Sci. 33: 112-119. Klose, A. A., E. L. R. Stokstad and H. J. Almquist, 1938. The essential nature of arginine in the diet of the chick. J. Biol. Chem. 123: 691-698. Kummerow, F. A., R. Weaver and H. Honstead, 1949. Choline replacement value of ethanolamine in chickens kept on a high-fat ration. Poultry Sci. 28: 475-478. March, B. E., and J. Biely, 1954. The nutritive value of fats of different origin in chick starters. Poultry Sci. 33: 1069. March, B. E. and J. Biely, 1956. Fat studies in poultry. 5. The effect of dietary fat level on the choline requirement of the chick. Poultry Sci. 35: 545-549. National Research Council, 1954. Nutrient Requirements for Domestic Animals. No. 1. Nutrient Requirements for Poultry. Pepper, W. F., S. J. Slinger and E. S. Snyder, 1953. Increasing the energy content of broiler diets high in wheat. Poultry Sci. 32: 921. Reiser, R., and P. B. Pearson, 1949. The influence of high levels of fat with suboptimum levels of riboflavin on the growth of chicks. J. Nutrition,

1285