Table 4. Effect of glycerin inclusion on nitrogen metabolism of rumen microorganisms in dual-flow continuous culture system.

Item 1	Glycerin, %			SEM	P-value
	0	15	30		Linear	Quadratic
NH3-N, mg/100ml	11.0	13.1	17.8	0.90	< 0.01	0.24
CP digestibility, %	79.4	67.6	65.9	1.82	< 0.01	0.04
Nitrogen flow, g/d
Total N	1.57	1.49	1.54	0.03	0.79	0.35
NH3-N	0.35	0.41	0.56	0.03	< 0.01	0.22
NAN	1.24	1.11	0.98	0.05	0.02	0.95
Microbial N	0.99	0.75	0.79	0.04	0.01	0.04
Dietary N	0.20	0.30	0.20	0.03	0.99	0.07
Microbial efficiency 2	23.9	19.4	20.4	0.78	0.09	0.07

¹NH₃-N = ammonia nitrogen; CP = crude protein; NAN = non-ammonia nitrogen; OM = organic matter.

²Microbial efficiency = g of microbial N/kg of OM truly digested.