Table 6.

Comparison of in vivo determined nitrogen and phosphorus intake, retention, and excretion with the calculated retention from NRC (2012) model, and blood urea nitrogen and creatinine of pigs fed with phase 2 grower diets¹

Items	CSBM	LP	DDGS	DDGS +IVT	SEM	P-value
Feed intake, kg/d	2.01	1.93	1.95	1.94	0.06	0.5285
N intake, g/d	54.89a	40.35c	48.26b	49.19b	1.39	<0.0001
N in feces, g/d	7.36b	6.33b	9.48a	9.11a	0.58	<0.0001
N in urine, g/d	15.93a	9.21b	12.12b	11.96b	1.35	0.0004
N excreted, g/d	23.28a	15.53b	21.59a	21.06a	1.32	<0.0001
N retained, g/d	31.61a	24.81b	26.67b	28.13b	1.27	0.0001
N digestibility, %2	86.60a	84.25a,b	80.50c	81.38b,c	2.28	0.0002
Net protein utilization, %3	57.75	61.44	55.26	57.14	2.76	0.073
Apparent biological value, %4	66.75	72.92	68.75	70.23	1.28	0.176
P intake, g/d	8.43a	6.79c	7.71b	7.14b,c	0.29	<0.0001
P in feces, g/d	4.39	4.14	3.94	3.83	0.26	0.1614
P retention of intake, %	47.89a	39.10b	49.08a	46.37a,b	2.89	0.0079
Predicted N retention5, %	30.23	38.12	36.77	36.52	–	–
Predicted P retention5, %	32.39	34.25	42.21	42.36	–	–
BUN6, mg/dL	10.41a	5.90b	8.18a,b	6.79b	1.23	0.0061
Creatinine, mg/dL	1.62	1.59	1.81	1.83	0.25	0.6983

¹DDGS = CSBM diet with 30% distillers dried grains with solubles; DDGS + IVT = DDGS diet supplemented with L-Ile, L-Val, and L-Trp.

²N digestibility = N digested/ N intake = (N intake—N feces)/ N intake × 100.

³Net protein utilization = N retained/ N intake = (N intake—N feces—N urine)/ N intake × 100.

⁴Apparent biological value = N retained/ N digested = (N intake—N feces—N urine)/ (N intake—N feces) × 100.

⁵Predicted N and P retention from the NRC (2012) model for a 50–75 kg pig.

⁶BUN, blood urea nitrogen.

^a,b,cValues with different superscripts within the columns are different (P < 0.05).