Table 4 Effects of dietary tryptophan levels and diquat injection on the activities of antioxidant enzymes and the malondialdehyde concentration in the plasma and liver of the weaned piglets

Plasma

 SOD, U/mL

142.51^a

138.17^a

135.20^a

106.65^c

118.94^bc

115.55^bc

6.76

0.81

< 0.05

0.47

 GPx, U/mL

698.32^b

811.76^a

810.08^a

665.55^b

768.24^ab

748.07^ab

38.60

0.62

0.08

0.66

 MDA, nmol/mL

2.43^b

2.53^b

2.48^b

3.53^a

3.58^a

3.68^a

0.21

0.89

< 0.05

0.94

Liver

 SOD, U/mg protein

564.43^a

579.77^a

595.80^a

469.14^b

516.04^ab

527.69^ab

31.64

0.74

< 0.05

0.09

 GPx, U/mg protein

95.63^a

95.71^a

95.56^a

76.04^b

90.03^a

99.44^a

5.20

0.18

< 0.05

0.05

 MDA, nmol/mg protein

1.60^a

1.27^b

1.56^a

1.74^a

1.44^ab

1.59^a

0.14

0.23

0.09

0.06