Table 5.

Effect of bacterial culture, enzyme and yeast additives on ruminal N flows and metabolism in a dual-flow continuous culture system

	Treatmenta					P-valueb
Item	CTRL	EB	EBY	2X	SEM	ADD	YEAST	DOSE
NH3-Nc, mg/dL	19.79	19.45	19.82	20.66	1.46	0.87	0.50	0.54
N flows, g/d
Total N	2.59	2.43	2.74	2.5	0.18	0.77	0.13	0.11
NH3-N	0.76	0.71	0.78	0.77	0.08	0.79	0.13	0.53
NANd	1.83	1.71	1.95	1.74	0.19	0.82	0.25	0.13
Bacterial N	0.91	0.84	0.99	0.84	0.14	0.80	0.45	0.17
Dietary N	0.92	0.87	0.97	0.91	0.08	0.98	0.43	0.53
RDP-Ne supply	2.49	2.52	2.43	2.49	2.32	0.92	0.46	0.55
RUP-Nf	0.92	0.87	0.97	0.91	0.08	0.98	0.43	0.53
ENUg	32.72	30.20	35.47	30.04	5.07	0.80	0.45	0.17
Bacterial efficiencyh	14.36	13.77	16.06	13.42	1.86	0.97	0.48	0.11

^aCTRL: no additives; EB: addition of enzymes and bacteria; EBY: addition of enzymes, bacteria and yeast; 2X-EBY: addition of enzymes, bacteria, and yeast at double the EBY dosage.

^bOrthogonal contrasts: ADD—CTRL vs. EB, EBY, and 2X; YEAST—EB vs. EBY and 2X; and DOSE—EBY vs. 2X.

^cAmmonia nitrogen.

^dNonammonia nitrogen.

^eRumen degraded protein N.

^fRumen undegraded protein N.

^gEfficiency of N use = g of bacterial N/g of available N.

^hBacterial efficiency = g of bacterial N/kg of OM truly digested.