TABLE 3.

Archaeal species detected in the rumen of nonlactating cows fed methane-reducing additives^c

Archaeal species	Relative abundance (%)
	Study 1a					Effect			Study 2b					Effect
	CTL	LIN	NIT	LIN+NIT	SEM	Linseed	Nitrate	lin×nit	CTL	TEA	NIT	TEA+NIT	SEM	Saponin	Nitrate	sap×nit
Methanobacterium alkaliphilum	0.04	0.71	0.03	0.01	0.002	0.166	0.126	0.138	0.01	0.56	0.05	0.00	0.001	0.184	0.173	0.120
Methanobrevibacter acididurans	0.01	0.00	0.01	0.01	0.000	0.966	0.506	0.649	0.00	0.00	0.00	0.01	0.000	0.448	0.876	0.623
Methanobrevibacter boviskoreani clade	2.72	1.44	2.72	1.86	0.018	0.502	0.891	0.887	3.89	0.50	0.40	2.46	0.018	0.776	0.740	0.234
Methanobrevibacter gottschalkii clade	38.08	45.63	21.10	19.28	0.051	0.584	<0.001	0.371	39.39	38.46	29.32	27.01	0.051	0.862	0.203	0.824
Methanobrevibacter oralis	0.47	0.34	0.32	0.25	0.001	0.158	0.115	0.641	0.27	0.46	0.30	0.27	0.001	0.271	0.250	0.137
Methanobrevibacter ruminantium clade	36.28	33.06	54.18	62.10	0.043	0.742	<0.01	0.365	33.80	37.75	47.87	47.66	0.043	0.766	0.107	0.735
Methanobrevibacter sp. strain RT	0.02	0.03	0.01	0.00	0.000	0.999	0.059	0.102	0.04	0.02	0.00	0.01	0.000	0.673	0.078	0.168
Other Methanobrevibacter	2.54	1.64	1.70	1.13	0.002	0.109	0.136	0.712	1.56	2.05	1.52	1.50	0.002	0.331	0.220	0.296
Methanosphaera cuniculi	0.22	0.04	0.25	0.23	0.001	0.575	0.561	0.668	0.05	0.09	0.08	0.10	0.001	0.641	0.760	0.774
Methanosphaera sp. strain A4	0.08	0.03	0.05	0.04	0.000	0.193	0.746	0.456	0.05	0.03	0.02	0.03	0.000	0.912	0.089	0.066
Methanosphaera sp. strain ISO3-F5	7.97	6.41	8.60	8.36	0.011	0.691	0.581	0.777	9.43	8.59	6.26	11.61	0.011	0.143	0.937	0.053
Other Methanosphaera	0.83	0.35	0.88	0.34	0.001	0.081	0.934	0.913	0.45	0.57	0.25	0.50	0.001	0.211	0.375	0.639
Other Methanobacteriaceae	0.07	0.05	0.08	0.05	0.000	0.255	0.976	0.806	0.04	0.05	0.04	0.06	0.000	0.418	0.841	0.565
Other Methanococcales	0.01	0.00	0.00	0.00	0.000	0.337	0.337	0.337	0.00	0.01	0.00	0.00	0.000	0.337	0.337	0.337
Methanomicrobium mobile	0.24	0.08	0.01	0.00	0.003	0.320	0.081	0.376	0.51	0.46	0.62	0.04	0.003	0.399	0.679	0.477
Other	0.09	0.07	0.00	0.01	0.001	0.918	0.156	0.849	0.00	0.23	0.00	0.01	0.001	0.257	0.306	0.311
Group 10 species	0.60	0.00	0.16	0.00	0.003	0.166	0.405	0.405	0.99	0.84	0.61	0.56	0.005	0.820	0.435	0.908
Candidatus “Methanomethylophilus alvus”	0.02	0.01	0.02	0.01	0.000	0.360	0.642	0.689	0.00	0.02	0.01	0.01	0.000	0.243	0.845	0.110
Group 12 species	1.99	2.21	2.50	2.05	0.006	0.902	0.878	0.745	1.51	2.41	3.27	2.36	0.006	0.999	0.244	0.218
Group 8 species	0.10	0.09	0.03	0.00	0.000	0.797	0.234	0.876	0.02	0.00	0.00	0.00	0.000	0.214	0.156	0.297
Group 9 species	0.03	0.02	0.09	0.16	0.001	0.677	0.244	0.648	0.04	0.21	0.03	0.02	0.001	0.052	0.025	0.039
Other Methanomassiliicoccaceae	2.96	3.12	3.87	1.58	0.000	0.842	0.687	0.226	2.74	1.51	3.44	1.67	0.000	0.987	0.859	0.883
Other	4.59	4.66	3.37	2.52	0.001	0.918	0.156	0.849	5.18	5.15	5.92	4.11	0.001	0.257	0.306	0.311

^aIn study 1, cows were fed a control (CTL) diet or CTL diet supplemented with linseed (LIN), nitrate (NIT), or linseed plus nitrate (LIN+NIT). Tested effects were linseed (CTL and NIT versus LIN and LIN+NIT) and nitrate (CTL and LIN versus NIT and LIN+NIT) and their interaction, lin×nit.

^bIn study 2, cows were fed a control (CTL) diet or CTL diet supplemented with tea saponin (TEA), nitrate (NIT), or tea saponin plus nitrate (TEA+NIT). Tested effects were saponin (CTL and NIT versus TEA and TEA+NIT) and nitrate (CTL and TEA versus NIT and TEA+NIT) and their interaction, sap×nit.

^cValues are the means from four observations, and analysis was performed on square root-transformed taxonomic tables using the aov function in R.