Table 8.

Effect of dietary CP content on essential microbial AA digestibility

Item	CP contents (g/kg of DM)1					Contrast2
	CR	100	120	140	SEM	RI vs. VI	Linear	Quadratic
Apparent absorption of essential microbial AA (g/d)
Arginine	13.1	14.8	17.6	19.9	1.87	0.04	0.05	0.90
Histidine	5.3	5.6	6.8	7.7	0.79	0.07	0.03	0.83
Isoleucine	13.8	14.8	17.8	22.0	1.89	0.03	0.01	0.74
Leucine	22.3	23.9	29.8	35.4	2.99	0.04	0.01	0.96
Lysine	19.0	21.4	24.8	28.5	2.93	0.05	0.06	0.95
Methionine	6.8	7.4	8.9	10.5	0.93	0.05	0.02	0.98
Phenylalanine	11.8	12.9	15.7	19.4	1.64	0.02	0.01	0.77
Threonine	13.7	14.9	17.7	21.1	1.68	0.03	0.01	0.89
Tryptophan	–	–	–	–	–	–	–	–
Valine	13.9	14.9	17.5	21.3	1.80	0.03	0.01	0.72
Apparent digestibility of essential microbial AA (%)
Arginine	80.0	74.6	78.2	78.9	2.50	0.33	0.23	0.62
Histidine	74.5	67.4	71.8	73.7	3.13	0.30	0.14	0.73
Isoleucine	76.9	70.6	73.2	77.2	2.93	0.28	0.08	0.82
Leucine	78.1	70.3	75.4	77.9	2.63	0.22	0.05	0.67
Lysine	81.5	82.3	84.8	78.3	2.20	0.10	0.18	0.62
Methionine	79.1	73.2	75.9	77.2	2.84	0.24	0.30	0.83
Phenylalanine	76.0	69.0	72.9	75.9	2.85	0.28	0.09	0.88
Threonine	78.5	71.9	74.8	76.8	2.60	0.16	0.15	0.87
Tryptophan	–	–	–	–	–	–	–	–
Valine	77.2	72.0	73.0	76.0	2.98	0.27	0.30	0.76
Total EAA microbial	78.8	72.3	75.6	77.8	2.57	0.20	0.12	0.84

¹Treatments: 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.

²RI vs. VI = restricted intake vs. voluntary intake (100, 120, and 140 CP g of CP/kg of DM).