Table 3.

Growth performance, physical body composition, and N utilization of nursery pigs fed low CP diets with reduced concentrations of Gly and Ser and supplemental Thr or Glu

	Dietary treatment1						P-value
	CON	G1	G2	T1	T2	SEM2	Dietary treatment3	N-source4
Initial BW, kg	15.1	15.3	15.1	15.1	14.9
Final BW, kg	25.5	25.6	25.7	24.9	25.3	0.3	0.800	0.142
ADG; wk 1 to 3	497	500	508	469	488	14	0.800	0.041
ADFI; wk 1 to 3	874	879	878	873	875	13	0.488	0.353
G:F; wk 1 to 3	0.57	0.57	0.58	0.54	0.56	0.01	0.240	0.060
Physical body composition5
Carcass, kg	20.9	21.2	21.1	20.2	20.4	0.3	0.616	0.050
Viscera, g	3,073	2,938	3,148	3,030	3,235	80	0.757	0.470
Gastrointestinal tract, g	1,549	1,524	1,666	1,672	1,675	61	0.237	0.263
Liver, g	435	437	453	460	441	17	0.694	0.896
Kidneys, g	115	126	125	132	121	6	0.729	0.898
N utilization6
N intake, g/d7	14.3ab	14.9ab	15.0a	14.1b	14.2ab	0.2	0.031	0.002
Carcass N Retention, g/d	10.0	10.7	10.3	8.7	9.6	0.6	0.240	0.364
Viscera N Retention, g/d8	0.7	0.6	0.8	0.6	0.8	0.1	0.246	0.668
Carcass + viscera N retention, g/d	10.7	11.3	11.1	9.3	10.4	0.6	0.267	0.406
Apparent N utilization efficiency,%	74.3	75.7	73.5	66.3	73.2	3.5	0.419	0.789

¹CON, control; G1, Gly supplied at 60% of CON and replaced with Glu; G2, Gly supplied at 20% of CON and replaced with Glu; T1, Gly supplied at 60% of CON and replaced with Thr; T2 Gly supplied at 20% of CON and replaced with Thr.

²Maximum value of the standard error of the means.

³ P-value for one-way ANOVA.

⁴ P-value for the effect of N source (G1+ G2 vs. T1 + T2).

⁵Physical composition for pigs at the end of the experimental period (i.e., day 21).

⁶N utilization calculated over the entire experimental period (i.e., 21 d); DM basis.

⁷SID N intake (NRC, 2012).

⁸Visceral fraction included heart, lungs, spleen, pancreas, kidneys, liver (drained gall bladder), and empty bladder and gastrointestinal tract.

^a,bMeans followed by different superscripts in the same row are different according to a Tukey’s multiple range test (P < 0.05).