Table 7 Effects of dietary Fe on activities of tissue Fe-containing enzymes of broilers on d 21

Control¹

0

2.21

19.0

16.2*

3.44*

4.34*

2.33*

28.7*

FeSO₄∙7H₂O¹

20

2.23

22.9

16.5

3.57

4.43

2.37

30.1

40

2.13

20.1

16.6

3.96

4.81

2.57

31.6

60

2.19

20.6

16.7

4.12

4.92

2.81

34.9

Fe-Prot ES¹

20

2.07

20.6

16.9

3.63

4.72

2.43

29.9

40

2.25

20.8

17.4

3.99

5.28

2.69

34.5

60

2.07

18.6

18.2

4.41

5.45

2.91

35.5

Feed grade NaFeEDTA¹

20

2.02

19.5

16.7

3.95

5.32

2.60

29.1

40

2.08

20.5

17.4

4.40

5.51

2.78

34.5

60

2.15

19.4

18.4

4.62

6.22

2.82

35.3

Food grade

NaFeEDTA¹

20

2.08

18.5

17.4

4.19

4.98

2.64

31.1

40

1.92

18.9

17.9

4.47

5.58

2.79

33.7

60

2.00

20.2

19.0

4.65

6.46

2.86

36.0

Pooled SE

0.18

1.40

0.41

0.31

0.36

0.17

1.71

Fe source²

FeSO₄∙7H₂O

2.18

21.2

16.6^B

3.88

4.72^B

2.58

32.2

Fe-Prot ES

2.13

19.8

17.5^A

4.00

5.15^AB

2.68

33.3

Feed grade NaFeEDTA

2.08

19.8

17.5^A

4.32

5.68^A

2.73

33.0

Food grade NaFeEDTA

2.00

19.2

18.1^A

4.44

5.67^A

2.76

33.6

Pooled SE

0.10

0.81

0.24

0.19

0.21

0.10

1.01

Added Fe level³, mg/kg

20

2.10

20.4

16.9^b

3.83^b

4.86^b

2.51^b

30.1^b

40

2.09

19.9

17.3^b

4.20^ab

5.29^ab

2.71^ab

33.6^a

60

2.10

19.7

18.1^a

4.45^a

5.76^a

2.85^a

35.4^a

Pooled SE

0.09

0.70

0.21

0.17

0.18

0.09

0.86

P-value

Fe source

0.6307

0.3541

0.0006

0.1672

0.0052

0.5973

0.7885

Added Fe level

0.9974

0.7886

0.0011

0.0480

0.0049

0.0244

0.0002

Fe Source × added Fe level

0.9529

0.6721

0.7452

0.9993

0.8438

0.9812

0.9456

Linear effect⁴

–

–

0.0002

0.0029

0.0006

0.0020

< 0.0001