Table 5.

Effects of dietary supplementation of glutamic acid to reduced protein diets on apparent total tract nutrient digestibility in weanling pigs at d 42 (%). ^1,2

Item	PC	NC	NC1	NC2	NC3	NC4	SEM	P-value
								PC vs. NC	Linear	Quadratic
Dry matter	81.40	79.29	79.97	80.02	80.92	80.83	1.55	0.345	0.464	0.917
Nitrogen	79.89	77.89	78.96	79.32	79.70	79.61	1.23	0.260	0.323	0.646
Energy	80.16	78.27	78.47	78.82	79.87	79.49	1.28	0.305	0.373	0.925

¹Values represent the means of randomly selected 8 pigs per treatment.

²PC (positive control), the basal standard protein diet with the Lys-to-Glu ratio at 1:2.35; NC (negative control), NC1, NC2, NC3, and NC4, the basal diet with 2% CP reduction and Lys-to-Glu ratios at 1:2.25, 1:2.30, 1:2.35, 1:2.40, and 1:2.45, respectively.