Table 9.

Effect of dietary CP content on nonessential microbial AA and digestibility

Item1	CP contents (g/kg of DM)2					Contrast3
	CR	100	120	140	SEM	RI vs. VI	Linear	Quadratic
Apparent absorption of nonessential microbial AA (g/d)
Alanine	17.7	18.7	22.9	26.7	2.50	0.08	0.03	0.93
Aspartic acid	28.4	36.4	39.8	48.8	3.43	0.01	0.03	0.51
Cystine	2.7	3.0	3.4	4.0	0.44	0.16	0.14	0.81
Glutamic acid	31.7	34.6	42.0	50.3	4.32	0.04	0.02	0.94
Glycine	17.2	18.9	23.5	26.0	2.23	0.05	0.04	0.70
Proline	10.9	11.6	15.0	17.4	1.74	0.08	0.04	0.82
Serine	12.3	13.6	16.3	19.3	1.58	0.03	0.01	0.96
Tyrosine	13.6	15.7	18.8	19.9	1.82	0.02	0.07	0.59
Apparent digestibility of nonessential microbial AA (%)
Alanine	73.4	64.7	69.1	70.4	3.44	0.16	0.21	0.68
Aspartic acid	80.4	78.3	79.0	80.2	2.55	0.67	0.60	0.93
Cystine	64.3	60.0	61.7	61.9	5.13	0.61	0.80	0.90
Glutamic acid	73.2	65.8	69.6	72.0	3.27	0.29	0.20	0.86
Glycine	79.1	71.1	76.7	77.6	2.45	0.17	0.07	0.43
Proline	76.2	65.9	74.3	76.6	3.42	0.32	0.04	0.46
Serine	80.0	72.0	77.3	78.9	2.49	0.18	0.07	0.55
Tyrosine	86.4	83.0	84.7	84.8	2.19	0.38	0.55	0.78
Total NE micAA1	77.3	71.0	74.6	76.1	2.64	0.27	0.18	0.74
AA total
Ap.Ab.4 (g/d)	254.1	283.1	338.3	398.1	32.88	0.02	0.01	0.94
AD5 (%)	78.0	71.6	75.1	76.9	2.60	0.24	0.15	0.78

¹Total NE micAA = total nonessential microbial AA.

²Treatments: RI = restricted intake to 1.2% BW containing 120 g of CP/kg of DM; 100, 120, and 140 = voluntary intake containing 100, 120, and 140 g of CP/kg of DM, respectively.

³RI vs. VI = restricted intake vs. voluntary intake (100, 120, and 140 CP g of CP/kg of DM).

⁴Ap.Ab = apparent absorption.

⁵AD = apparent digestibility.