Table 6.

Community structure of ruminal archaea in solid phase as affected by incubation conditions and betaine supplementation in vitro.

	Osmolality1			Temperature (°C)			Betaine2				P value
	Normal	Hyper	SE∗	39.5	42	SE∗	Control	Low	High	SE∗	O 3	T 3	B 3	Interaction4
Phyla
Crenarchaeota	0.001	0.001	0.0008	0.002	5 × 10−4	0.0008	5 × 10−4	0.001	0.002	0.001	0.98	0.10	0.26
Euryarchaeota	0.99	0.99	0.0007	0.991	0.993	0.0007	0.994	0.993	0.991	0.001	0.19	0.07	0.09
Genera
Vadin CA11	0.27	0.26	0.016	0.293	0.2426	0.0162	0.288	0.253	0.260	0.018	0.56	0.001	0.15
Methanosphaera	0.13	0.13	0.0308	0.115	0.159	0.030	0.119	0.0328	0.166	0.125	0.96	0.06	0.19
Methanosarcina	2 × 10−5	2 × 10−4	1 × 10−4	2 × 10−4	1 × 10−5	1 × 10−4	1 × 10−5	2 × 10−4	9 × 10−5	1 × 10−6	0.29	0.20	0.46
Methanobrevibacter	0.45	0.50	0.0208	0.494	0.463	0.0208	0.487	0.454	0.494	0.023	0.02	0.14	0.26	(O × T)
Methanobacterium	3 × 10−5	3 × 10−5	7 × 10−6	3 × 10−5	3 × 10−5	7 × 10−6	2 × 10−5	3 × 10−5	4 × 10−5	7 × 10−6	0.58	0.42	0.16
Methanimicrococcus	0.01	0.003	0.002	0.0045	0.011	0.0025	0.006	0.005	0.011	0.003	0.02	0.05	0.33	(O × T)

¹Normal osmolality ~ 295 mOsmol kg⁻¹; hyperosmolality ~ 420 mOsmol kg⁻¹. ²Betaine levels: control (0), low (51), and high (286) ppm. ³O: osmolality; T: temperature; B: betaine. ⁴Only effects with significance (P ≤ 0.05) or tendency marked with bracket (P ≤ 0.10) are listed. ^∗Standard error. ^$P value is for testing the fixed effect of osmolality (n = 36), temperature (n = 36), and betaine addition (n = 24). Significance: P < 0.05.