Table 4.

Effects of inclusion of different additives in diets with 2 levels of concentrate on nitrogen metabolism parameters in a dual-flow continuous culture system

Item†	Concentrate level‡		Additives§					SEM	P-value
	Low	High	Control	Yeast cells	Blend 1	Blend 2	Monensin		Diet	Additive	Diet × Addit
Microbial efficiency, g/kg	193	236	202	234	215	198	224	23.2	0.03	0.77	0.51
N efficiency, g/kg	477	701	548	639	581	536	641	58.0	<0.01	0.53	0.51
N capture, g/kg	385	593	454	531	483	444	534	47.8	<0.01	0.51	0.49
Flow, g
N	1.07	1.62	1.35	1.35	1.29	1.39	1.32	0.07	<0.01	0.81	0.64
NH3–N	0.027	0.023	0.023	0.032	0.022	0.022	0.027	0.005	0.36	0.34	0.12
NAN	1.04	1.60	1.33	1.32	1.27	1.37	1.29	0.064	<0.01	0.81	0.70
Bacterial N	0.59	1.11	0.78	0.92	0.84	0.76	0.93	0.082	<0.01	0.43	0.41
RUP-N	0.45	0.49	0.55ab	0.39c	0.43bc	0.62a	0.36c	0.065	0.67	<0.01	0.50

^a,b,cDifferent letters on the same line indicate significant differences between means related to additives (P < 0.05).

^†N = nitrogen; NH₃–N = ammoniacal nitrogen; NAN = non-ammonia nitrogen; RUP = undegradable protein.

^‡High (80% concentrate), low (20% concentrate).

^§Control—diet without additive inclusion; Yeast cells (Saccharomyces cerevisiae) hydrolyzed, inactivated, and dried by spray at 2,133 mg/kg DM (BioHydro Yessinergy LTDA, Campinas, SP, Brazil); Blend 1—yeast culture (Saccharomyces cerevisiae), beta-glucans, fructooligosaccharides, galactooligosaccharides, and mannanoligosaccharides at 1,600 mg/kg DM (Golf Yessinergy LTDA, Campinas, SP, Brazil); Blend 2—beta-glucan and mannanoligosaccharide fractions from Saccharomyces cerevisiae at 1,600 mg/kg DM (GlucanMos Yessinergy LTDA, Campinas, SP, Brazil); Monensin (Rumensin, 25 mg/kg DM).