Table 6 Effects of dietary threonine levels on activities of AP, γ-GT, CK and Na⁺/K⁺-ATPase in intestine of sub-adult grass carp^f

 PI

69.5 ± 7.3^a

84.4 ± 8.1^b

102.8 ± 10.1^cd

108.0 ± 10.7^d

125.0 ± 10.4^e

92.8 ± 9.1^bc

 MI

110.1 ± 7.0^c

120.3 ± 13.0^cd

125.8 ± 4.9^d

117.6 ± 8.2^cd

91.9 ± 8.6^b

71.3 ± 7.4^a

 DI

72.2 ± 6.9^c

80.3 ± 7.5^d

69.0 ± 5.4^c

54.7 ± 5.3^b

53.8 ± 2.6^b

35.8 ± 2.8^a

 PI

1.82 ± 0.16^a

2.27 ± 0.15^b

2.59 ± 0.28^c

2.52 ± 0.15^c

3.00 ± 0.16^d

2.24 ± 0.23^b

 MI

2.12 ± 0.16^a

2.89 ± 0.26^b

3.05 ± 0.21^b

3.09 ± 0.17^b

2.93 ± 0.19^b

2.94 ± 0.28^b

 DI

0.73 ± 0.08^a

0.87 ± 0.11^b

1.20 ± 0.07^c

1.23 ± 0.12^c

1.13 ± 0.11^c

0.76 ± 0.06^ab

 PI

2.62 ± 0.25^c

2.72 ± 0.19^c

2.74 ± 0.24^c

3.11 ± 0.29^d

1.52 ± 0.13^b

1.14 ± 0.13^a

 MI

1.36 ± 0.09^a

2.40 ± 0.18^c

2.35 ± 0.17^c

4.47 ± 0.44^d

4.28 ± 0.34^d

1.77 ± 0.17 ^b

 DI

6.69 ± 0.73^a

7.26 ± 0.44^a

6.96 ± 0.67^a

9.35 ± 0.45^b

8.86 ± 0.70^b

7.15 ± 0.75^a

 PI

0.37 ± 0.06^b

0.42 ± 0.05^c

0.41 ± 0.02^c

0.36 ± 0.03^b

0.37 ± 0.03^b

0.30 ± 0.03^a

 MI

0.48 ± 0.04^c

0.62 ± 0.04^d

0.47 ± 0.03^bc

0.43 ± 0.04^ab

0.39 ± 0.03^a

0.39 ± 0.04^a

 DI

0.35 ± 0.02^a

0.34 ± 0.02^a

0.35 ± 0.02^a

0.36 ± 0.01^a

0.35 ± 0.03^a

0.35 ± 0.02^a