Table 5.

Effect of microencapsulated organic acids and pure botanicals on N metabolism in a dual-flow continuous-culture system

Parameter1, %	Level of inclusion2				SEM	P-value3
	0	30	60	90		Lin	Quad
NH3–N, mg/dL	4.49	4.11	4.47	4.41	0.48	0.91	0.49
Total N4	2.35	2.38	2.41	2.41	0.11	0.68	0.84
NH3–N5	0.19	0.18	0.20	0.19	0.02	0.81	0.93
NAN6	2.15	2.20	2.21	2.21	0.11	0.69	0.85
Bacteria N7	1.16	1.10	1.12	1.16	0.07	0.88	0.42
Dietary N8	1.00	1.10	1.09	1.05	0.06	0.63	0.32
ENU9	41.9	45.7	44.8	43.9	1.45	0.48	0.15
Bacterial efficiency10	19.3	19.6	18.8	19.6	1.43	0.95	0.83
RDP-N supply11	2.50	2.40	2.43	2.47	0.06	0.78	0.37
RDP-N supply12	71.5	68.7	69.1	70.1	1.83	0.66	0.34
RUP-N supply11	0.99	1.10	1.09	1.05	0.06	0.63	0.32
RUP-N supply12	28.5	31.3	30.9	29.9	1.83	0.66	0.34

¹Apparent degradability is the percentage of the nutrient degraded and true degradability is the percentage of the nutrient degraded discounting for the nutrient present in the bacterial pellet.

²Levels of inclusion ranging from 0 to 90 g/25 kg of total mixed ration.

³Contrast: linear and quadratic, there was no cubic effect, thus P-values are not presented.

⁴Total N =  total N flow (g/d) = NH₃-N + NAN (Bach and Stern, 1999).

⁵NH₃–N = ammonia N flow (g/d) = mg/dL of effluent NH₃–N × (g of total effluent flow/100).

⁶NAN = nonammonia N flow (g/d) = total N − NH₃-N.

⁷Bacterial-N flow (g/d) = (NAN flow × % atom excess of 15N in NAN effluent)/(% atom excess of ¹⁵N in bacteria pellet), according to Calsamiglia et al. (1996).

⁸Dietary N flow (g/d) = g of effluent NAN − g of effluent bacterial N.

⁹ENU = efficiency of N use = (g of bacterial N/g of available N) × 100 (Bach and Stern, 1999).

¹⁰Bacterial efficiency = g of bacterial N flow/kg of OM truly digested (Calsamiglia et al., 1996).

¹¹N supply = g/d.

¹²N supply %.