Phenylalanine and Threonine Levels for Young Chicks1

Phenylalanine and Threonine Levels for Young Chicks 1 B. A. KRATJTMANN, S. M. HAUGE, E. T. MERTZ AND C. W. CARRICK

Purdue University Agricultural Experiment Station, Lafayette, Indiana (Received for publication August 30, 1957)

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RAU (1947) indicated that chicks require 0.6 to 0.8 percent DL-phenylalanine in the diet plus an equal amount of tyrosine. Almquist (1952) and the National Research Council (1954) gave the requirement for phenylalanine as 1.6 percent of the diet, 0.7 percent of which may be replaced by tyrosine. Fisher (1956) found the phenylalanine requirement to be about 0.5 percent of the diet in the presence of excess tyrosine. Almquist and Grau (1944) indicated that 1.0 percent DL-threonine appeared to be insufficient to support growth in a diet composed of pure amino acids. Wilkening et al. (1947) stated that 0.67 percent L-threonine from oxidized casein and gelatin apparently satisfied the chicks' requirement for threonine. Grau (1949) concluded that the L-threonine requiredent is approximately 0.45 percent of the diet. DL-threonine was only onehalf as active as L-threonine. Lewis (1951) reported that a diet containing 27 percent crude protein from wheat gluten and gelatin was deficient in threonine. The calculated threonine content was reported as being 0.58 percent of the diet. Almquist (1952) gives the threonine requirement as 0.6 percent L-threonine in a 20 percent protein diet. PROCEDURE In all trials Barred Plymouth Rock males were placed on the same diet for the first week in order to decrease yolk protein carry-over. At the end of the one1 Journal Paper No. 1149 of the Purdue University Agricultural Experiment Station.

week period the chicks were weighed individually, sorted into blocks according to weight, and distributed into the experimental lots. The extremely large and small chicks were discarded. All chicks were reared in electrically heated battery brooders, with wire floors. Rations and tap water were supplied ad libitum. The chicks were weighed individually at weekly intervals. Gains were treated statistically by analysis of variance. The protein ingredients were assayed microbiologically by the methods of Steele et al. (1949) using Leuconostoc citrovorum 8081 as the test organism. The assay values for phenylalanine were as follows: (percent) corn, 0.47; isolated soybean protein (Drackett), 4.22; gelatin, 1.95; and fish solubles, 0.80. The tyrosine values were as follows: (percent) corn, 0.56; isolated soybean protein, 2.83; gelatin, 0.43; and fish solubles, 0.19. Threonine values for casein and fish solubles were 3.44 and 0.68 percent respectively. The composition of the basal diets used is shown in Table 1. Amino acid additions were made at the expense of glucose. RESULTS AND DISCUSSION

Trial 1 was conducted to determine the phenylalanine requirement in an isolated soybean protein-gelatin diet. In Lots 1 through 4 corn was added in view of the results obtained with arginine in which the addition of corn gave maximum growth on a lower arginine level, Krautmann et al. (1956). The results of Trial 1 are shown in Table 2. No significant growth response was obtained by the addition of phenylalanine to either basal

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B. A. KRAUTMANN, S. M. HAUGE, E. T. MERTZ AND C. W. CARRICK

536

phenylalanine requirement to be about 0.5 percent in the presence of excess tyrosine. His diets calculate about 0.7 percent tyrosine which would be approximately 1.2 percent of total aromatic amino acids in his diets. Trial 2 was conducted to determine the threonine requirement in a casein diet. The results are shown in Table 3. Growth on the 0.54 percent threonine ration (Lot 9) was significantly less than that obtained on higher levels of threonine, however, the growth in the other lots was variable. It is probable that arginine was limiting in Lots 10 through 13, since these diets contained only approximately 1.3 percent arginine, which was later found to be inadequate in a casein diet, Krautmann el al. (1956). The results of Trial 3 are shown in Table 4. In this trial additional arginine was supplied. A significant growth response was obtained by the addition of 0.10 percent DL-threonine to the basal containing 0.55 percent threonine (Lots 14 and 15). Addition of greater increments of threonine was without significant effect. Growth on the purified diets was less than that obtained on a corn-soybean

TABLE 1.—Composition of basal diets Basal number A Ingredients (gms.): Glucose Ground corn Isolated soy protein (Drackett) Gelatin Alcohol extracted casein Mineral mixture* Fish solubles Vitamin mixture** Soybean oil DL-methionine DL-leucine DL-tryptophan DL-threonine L-arginine HC1 Glycine L-glutamic acid DL-phenylalanine Total

c

B

D

40.69 62.33 61.47 60.17 25.00 9.00 13.00 11.00 10.00 1.00 15.00 15.00 5.57 5.57 5.57 5.57 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 2.00 2.00 5.00 5.00 0.50 0.60 0.50 0.50 0.40 0.14 0.10 0.06 0.06 0.10 0.90 1.20 2.00 2.00 3.00 3.00 0.50 0.50

— — — — — — — — —

— — — —

— — — — — — — — —

100.00 100.00 100.00 100.00

* Mineral mixture (percent): K2HPO4, 0.85; Na2HP04, 0.52; NaCl (iodized), 0.502; MgS04 ' 7 H 2 0 , 0.50; F e ( C e H O ? ^ • 6H2O, 0.14; ZnS04, 0.005; CUSO4 • 5 H 2 0 , 0.002; H3BO3, 0.0009; CoCl2-6H 2 0, 0.0001; M n S 0 4 (tech.), 0.05; ground limestone, 1.50; Caa (P04) 2 , 1.50. ** Vitamin mixture (mgs. per 100 gms. feed); riboflavin, 0.466; niacin, 4.960; Ca pantothenate, 2.332; biotin, 0.033; folic acid, 0.242; inositol, 15.000; menadione (vitamin K ) , 0.100; thiamine, 0.551; pyridoxine hydrochloride, 0.904; choline chloride (25%), 150.00; B12, 0.00066; procaine penicillin, 0.440; vitamin E, 0.555 I.U./100 gms.; vitamin A (5,000 A), 1,000.0 I.U./100 gms.; vitamin D (1,500 D3), 150 I.C.U./100 gms.; glucose to total 3 percent.

diet containing 1.18 percent total aromatic amino acids2 with or without corn. These diets were higher in phenylalanine but lower in tyrosine than those used by Fisher (1956) in which he found the 2

Aromatic amino acids will refer to phenylalanine and tyrosine in this discussion.

TABLE 2.—Phenylalanine and tyrosine levels for young chicks Lot number

Ingredients (gms.): Basal A Basal B DL-phenylalanine

1

2

3

4

100.00

99.80

99.50

99.20

.20

.50

.80

.83 .45 1.28

.98 .45 1.43

1.13 .45 1.58

L-phenylalanine, % L-tyrosine, % Total L-aromatic, % Ave. 4 wk. wts. (gms.) 1-4 wk. gains (gms.)* No. chicks, males

.73 .45 1.18 365 292 25

* Least significant difference: 5 percent: 14 gms. 1 percent: 18 gms.

353 280 25

351 278 25

355 282 25

5

6

7

8

100.00

99.80 .20

99.50 .50

99.20 .80

.77 .41 1.18

.87 .41 1.28

1.02 .41 1.43

1.17 .41 1.58

362 289 25

364 291 25

361 288 25

363 290 25

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PHENYLALANINE AND THREONINE FOR CHICKS TABLE 3.—Quantitative requirement of threonine Lot number

Ingredients (gms.): Basal C DL-threonine

9

10

11

12

13

100.00

99.95 .05

99.90 .10

99.85 .15

99.80 .20

.54

.56

.59

.61

.64

L-threonine, % Ave. 3 wk. wts. (gms.) Ave. 1-3 wk. gains (gms.)* No. chicks, males :

207 137 15

240 170 15

241 171 15

225 155 15

225 155 15

Least significant difference: 5 percent: 18 gms. 1 percent: 23 gms.

oil meal diet (Lot 18). In the purified diets supplementation with pure amino acids was made when there was a question of adequacy. The total protein level was increased to 21 percent by the addition of glutamic acid and excess glycine. Addition of these pure amino acids may have caused an imbalance, or more likely the needed unidentified factors may not have been supplied in the casein diets which did contain fish solubles. In view of these results it is very unlikely that deficiencies of the aromatic amino acids, phenylalanine and tyrosine, or threonine will present a problem in

practical formulation of diets for young chicks. SUMMARY Under the conditions of these experiments the results indicate that: 1. The aromatic amino acid requirement was satisfied at 1.18 percent of the diet both with or without corn when isolated soybean protein and gelatin were used as primary sources of protein. 2. The minimum L-threonine requirement lies between 0.55 and 0.6 percent in a 21 percent protein diet.

TABLE 4.—Quantitative requirement of threonine Lot number

Ingredients (gms.): Basal D DL-threonine

14

15

16

17

18

100.00

99.90 .10

99.80 .20

99.70 .30

corn-soybean meal control*

.55

.60

.65

.70

L-threonine, % Ave. 3 wk. wts. (gms.) Ave. 1-3 wk. gains (gms.)** No. chicks, males

207 140 15

225 159 15

227 161 15

231 165 15

260 190 15

* Percentage composition: Gr. corn, 49.75; soybean oil meal, 36.00; vitamin mixture (Table 1), 3.00; soybean oil, 5.00; DL-methionine, 0.15; fish solubles, 3.00; limestone, 1.50; C a H P 0 4 2 H O H , 1.10; iodized salt, MnS0 4 (9-1), 0.50. ** Least significant difference: 5 percent: 16 gms. 1 percent: 21 gms.

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B. A. KRAUTMANN, S. M. HAUGE, E. T. MERTZ AND C. W. CARRICK REFERENCES

Almquist, H. J., 1952. Amino acid requirements of chickens and turkeys—A review. Poultry Sci. 31: 966-981. Almquist, H. J., and C. R. Grau, 1944. The amino acid requirement of the chick. J. Nutrition, 28: 325-331. Fisher, H., 1956. The L-phenylalanine requirement of the chick. Arch. Biochem. Biophysics, 60: 108114. Grau, C. R., 1947. Interrelations of phenylalanine and tyrosine in the chick. J. Biol. Chem. 170: 661-669. Grau, C. R., 1949. The threonine requirement of the chick. J. Nutrition, 37: 105-114. Krautmann, B. A., S. M. Hauge, E. T. Mertz and C. W. Carrick, 1956. The arginine level for chicks

as influenced by ingredients. Poultry Sci. 35: 1153. Lewis, E. E., C. A. Elvehjem and E. B. Hart, 1951. Studies on the nature of the nutritional deficiencies of wheat gluten meal. J. Nutrition, 43: 113— 130. National Research Council, Nutrient Requirements of Poultry. 1954. Steele, B. S., H. E. Sauberlick, M. S. Reynolds and C. A. Baumann, 1949. Media for Leuconosloc Mesenteroides P-60 and Leuconostoc Citrovorum 8081. J. Biol. Chem. 177: 533-544. Wilkening, M. C , B. S. Schweigert, P. B. Pearson and R. M. Sherwood, 1947. Studies on the requirement of the chick for tryptophan. J. Nutrition, 34: 701-714.

The Vitamin A Content of Fresh and Stored Shell Eggs* SELMA L. BANDEMER, ROBERT JOHN EVANS AND J. A. DAVIDSON Departments of Agricultural Chemistry and Poultry Husbandry, Michigan State University of Agriculture and Applied Science, East Lansing, Michigan (Received for publication October 9, 1957)

T

HE vitamin A content of fresh and stored shell eggs has been determined as part of a study of changes in composition occurring when shell eggs are kept in cold storage. Egg yolk is one of the better food sources of vitamin A, one egg furnishing 4 to 16 percent of the daily requirement (Boucher, 1941). Any losses of vitamin A from such a rich dietary source is of importance nutritionally. Large numbers of eggs are stored for extended times, and so-called fresh eggs are usually several days old before they are eaten. According to previous work from this laboratory, eggs stored for 12 months lost 18 percent of the niacin (Evans et al., 1951a), 51 percent of the vitamin B6 (Evans et al., 1951b), 14 percent of the riboflavin (Evans et al., 1952a), 8 percent

* Journal Article No. 2056 from the Michigan Agricultural Experiment Station.

of the pantothenic acid (Evans el al., 1952b), 27 percent of the folic acid (Evans et al., 1953a), and 33 percent of the vitamin B12 (Evans et al., 1955), but did not lose choline (Evans and Davidson, 1951) nor biotin (Evans et al., 1953b). Published data are conflicting as to changes in vitamin A content of eggs during storage (Jones et al., 1924-25; Manville, 1926). Preliminary work here indicated that a very large proportion of the vitamin A in hen's eggs was lost during storage. The data presented herein were obtained over several years under different experimental conditions. EXPERIMENTAL

The eggs used in the three experiments were produced by S. C. White Leghorn pullets housed in individual laying cages and fed a ration of constant composition. The ration contained ground corn 34.5 percent, ground oats 20.0 percent, wheat