Table 8.

Effect of AFEX wheat straw diet and a recombinant fibrolytic enzyme on nitrogen (N) utilization by wethers (n = 8 per treatment)

	Control		AFEX1			P-value
Item	Enz− 2	Enz+ 3	Enz−	Enz+	SEM	Diet	Enz4	Diet × Enz
N intake, g/d	44.8	44.3	41.9	38.1	3.69	0.16	0.50	0.61
Fecal N, g/d	11.7	10.3	12.9	11.7	1.01	0.10	0.09	0.92
Urine N, g/d	17.5	19.9	18.3	17.6	1.61	0.56	0.48	0.20
RN5, g/d	14.4	14.4	9.8	10.3	2.57	0.01	0.87	0.84
RN/N intake, %	31.0	32.1	21.1	25.4	4.35	0.02	0.36	0.58
RN/digested N, %	41.5	41.6	30.6	36.5	5.55	0.05	0.41	0.41
RN, g/kg BW0.75	0.69	0.74	0.48	0.52	0.122	0.02	0.53	0.98

¹AFEX = ammonia fiber expansion treatment (30% AFEX straw pellets on a dietary DM basis replacing alfalfa hay pellets).

²Enz− = diet without enzyme.

³Enz+ = diet with enzyme.

⁴Enz = recombinant fibrolytic enzyme treatment effect (XYL10C, a β-1,4-xylanase, EC 3.2.1.8, GH10 from Aspergillus niger).

⁵RN = retained N.