Table 5.

Effect of AFEX wheat straw diet and a recombinant fibrolytic enzyme on ruminal abundance of archaea and bacteria, and phylum-level taxonomic composition of the most abundant bacterial communities (%) in the ruminal contents of wethers (n = 8 per treatment)

	Control		AFEX1			P-value
Item	Enz− 2	Enz+ 3	Enz−	Enz+	SEM	Diet	Enz4	Diet × Enz
Archaea	2.4	2.4	2.7	2.2	0.265	0.81	0.35	0.46
Bacteria	97.6	97.6	97.3	97.8	0.265	0.81	0.35	0.46
Bacteroidetes	46.0	44.9	50.7	47.8	3.53	0.17	0.46	0.72
Firmicutes	36.8	36.7	31.1	34.8	2.25	0.02	0.28	0.23
Spirochaetes	7.0	6.3	9.1	9.0	1.26	<0.01	0.61	0.66
Fibrobacteres	2.9	2.0	2.0	2.4	0.47	0.56	0.51	0.18
Actinobacteria	2.4	2.0	1.7	1.1	0.44	0.02	0.14	0.70
Proteobacteria	0.9	1.3	1.0	1.2	0.26	0.92	0.28	0.67
Kiritimatiellaeota	0.7	1.2	0.3	1.1	0.32	0.03	<0.001	0.12
Synergistetes	0.7	0.8	0.7	0.5	0.21	0.30	0.61	0.15
Planctomycetes	0.4	0.5	0.2	0.6	0.03	0.60	0.21	0.45
Others (<0.5%)	0.9	1.0	0.8	1.1	0.27	0.99	0.25	0.47

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).