Table 2.

Dietary intake, apparent digestibility, N balance, and total tract passage rate of growing steers in response to i.v. infusion of LPS and abomasal infusion of BCAA

Item	Treatment1				SEM	P-value
	−LPS		+LPS
	−BCAA	+BCAA	−BCAA	+BCAA		LPS×BCAA	LPS	BCAA
n	5	5	5	3
Intake, kg/d
DM	2.49	2.62	1.77	2.31	0.19	0.27	0.01	0.09
OM	2.30	2.41	1.63	2.13	0.18	0.27	0.01	0.09
NDF	1.01	1.06	0.70	0.95	0.08	0.20	0.01	0.06
ADF	0.69	0.72	0.51	0.64	0.07	0.34	0.03	0.12
Apparent digestibility, %
DM	78.6	76.1	80.8	78.2	1.31	0.98	0.19	0.12
OM	80.3	78.2	82.7	79.8	1.23	0.78	0.19	0.11
NDF	72.4	68.8	76.9	72.9	2.14	0.95	0.11	0.16
ADF	72.4	68.8	76.2	72.5	1.92	0.98	0.13	0.13
N balance
Dietary N intake, g/d	58.2	61.1	41.2	53.3	4.58	0.31	0.01	0.11
Infused N, g/d	6.3	10.2	6.3	10.2	—	—	—	—
Total N supply, g/d	64.4	71.2	47.4	63.5	4.58	0.31	0.01	0.02
Fecal N, g/d	15.7	18.0	10.2	14.5	1.50	0.49	<0.01	0.03
Urinary N, g/d	29.7	29.0	30.4	33.5	1.31	0.25	0.11	0.45
Apparent N digested
g/d	48.7	53.1	37.2	49.0	3.30	0.30	0.04	0.03
% of total N supply	76.1	74.8	78.3	77.2	1.23	0.95	0.13	0.43
Retained N
g/d	18.9	24.0	6.5	15.6	3.56	0.65	0.02	0.11
% of total N supply	28.6	33.9	6.0	24.5	9.69	0.57	0.18	0.31
Urinary NMH3
mmol/d	3.60	3.51	4.04	4.76	0.52	0.49	0.15	0.59
Daily µmol/kg of BW	2.04	1.98	2.31	2.75	0.23	0.33	0.05	0.46
Passage, %/h
Cr	4.17	4.43	1.95	2.27	0.40	0.92	<0.01	0.37
Yb	3.07	3.55	1.96	2.03	0.50	0.67	0.02	0.56

¹A 2 × 2 factorial arrangement of intravenous infusions (1 mL/min) of 100 mL sterile saline containing either 0 μg or 1.0 to 1.5 μg of LPS per kg of BW (−LPS vs. +LPS), and abomasal infusions of an essential AA solution that supplied either 0 or 35 g/d BCAA (−BCAA vs. +BCAA).

²n = steers per treatment; 2 steers receiving the +LPS and +BCAA treatment combination were removed from the experiment due to severe respiratory reactions to the LPS infusions. LPS = lipopolysaccharide; BCAA = branched-chain AA.

³N^τ-methylhistidine excreted in urine.