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Table 1 The University of Illinois patterns of amino acid compositions in ideal proteins for chicks during the first three wk post-hatching 1

From: Dietary requirements of synthesizable amino acids by animals: a paradigm shift in protein nutrition

Amino acid

Amino acid content in the carcass Ref.[29] (% of crude protein)2

Dean & Scott standard (1965) Ref.[33]

Huston & Scott standard (1968) Ref.[34]

Sasse & Baker standard (1973) Ref.[35]

Baker & Han standard (1994) Ref.[36]

Amount in diet3

% of lysine

Amount in diet3

% of lysine

Amount in diet3

% of lysine

Amount in diet3

% of lysine

Arginine

6.65

1.10

98.2

1.00

105

0.95

104

0.95

106

Cystine

---

0.35

31.3

0.35

36.8

0.35

38.5

0.325

36.1

Glycine

---

1.60

143

1.20

126

0.60

65.9

0.60

66.7

Isoleucine

4.35

0.80

71.4

0.60

63.2

0.60

65.9

0.60

66.7

Histidine

1.80

0.30

26.8

0.30

31.6

0.33

36.3

0.32

35.6

Leucine

7.2

1.20

107

1.20

126

1.00

110

0.98

109

Lysine

6.6

1.12

100

0.95

100

0.91

100

0.90

100

Methionine

1.98

0.55

49.1

0.35

36.8

0.35

38.5

0.325

36.1

Phenylalanine

4.25

0.68

60.7

0.50

52.6

0.50

55.0

0.50

55.6

Proline

---

1.00

89.3

0.20

21.1

0.40

44.0

0.40

44.4

Threonine

4.4

0.65

58.0

0.65

68.4

0.65

71.4

0.60

66.7

Tryptophan

0.98

0.23

20.5

0.15

15.8

0.15

16.5

0.145

16.1

Tyrosine

---

0.63

56.3

0.45

47.4

0.45

49.5

0.45

50.0

Valine

5.0

0.82

73.2

0.82

86.3

0.69

75.8

0.69

76.7

Glutamic acid4

---

12.0

1071

10.0

1053

12.0

1319

12.0

1333

Total amino acids

 

23.0

 

18.7

 

19.9

 

19.8

 

Total nitrogen

 

2.83

 

2.33

 

2.37

 

2.35

 
  1. 1These ideal protein models were developed for 0- to 21-d-old broilers using crystalline amino acids. It was assumed that all of these amino acids were 100% available for absorption into enterocytes in chicks. Except for glycine and methionine, all amino acids are L-isomers. DL-methionine is used herein.
  2. 2Average values for 1-wk-old and 4- to 5-wk-old chicks.
  3. 3% of diet (as-fed basis; 90% dry matter).
  4. 4Provided as the nitrogenous source for synthesis of NEAA in chicks.
  5. This value refers to L-methionine.