Rumen microbial degradation of bromoform from red seaweed (Asparagopsis taxiformis) and the impact on rumen fermentation and methanogenic archaea

Table 6 Effect of bromoform at different concentrations (C) and incubation times (T) on CH₄ inhibition rate (%) in different archaeal species (Exp. 2)

	BES 100 µmol/L	CHBr₃ concentration, µmol/L				SEM	Contrasts C	Time							SEM	Contrasts T
	BES 100 µmol/L	0.4	2	10	50	SEM	Contrasts C	d 2	d 5	d 7	d 9	d 12	d 15	d 17	SEM	Contrasts T
Methanobrevibacter smithii	17.8 ± 3.46	14.3^b	19.0^b	34.4^a	32.9^a	2.96	L^, Q^*	27.5^abc	35.4^a	32.3^ab	28.5^abc	20.0^bcd	17.7^cd	14.5^d	3.92	L^**
Methanobrevibacter ruminantium	60.3 ± 4.05	58.4	62.9	71.1	68.7	3.98	Q^†	54.2^b	72.2^ab	54.5^b	60.3^bc	60.3^bc	76.1^a	79.1^a	5.26	L^**
Methanosphaera stadtmanae	31.2 ± 3.35	54.8^b	73.7^a	75.4^a	76.6^a	1.71	L^, Q^*	89.9^a	72.7^b	73.8^b	74.0^b	56.7^c	58.2^c	65.7^bc	2.26	L^**, Q
Methanosarcina barkeri	40.3 ± 3.81	37.6^ab	24.7^b	31.8^ab	46.5^a	3.28	L^*	29.9	28.7	28.5	35.0	38.9	40.8	44.2	4.34	L^†
Methanobrevibacter millerae	28.7 ± 5.14	42.0^b	63.3^a	69.2^a	75.6^a	5.56	L^*, Q^	47.5^c	54.6^bc	53.4^bc	71.6^ab	77.1^a	69.9^ab	63.8^abc	7.35	L^*, Q^†
Methanothermobacter wolfei	19.6 ± 5.75	30.5^b	39.9^ab	48.6^a	48.4^a	3.42	L^, Q^*	43.3^a	20.5^b	47.9^a	50.6^a	40.0^a	42.7^a	47.8^a	4.52	NS
Methanobacterium mobile	10.2 ± 4.05	22.3^b	33.3^a	19.9^b	30.1^a	2.67	Q^†	30.7^b	20.1^d	16.0^d	23.5^bcd	43.7^a	20.6^cd	30.3^bc	3.53	NS

In the first column, mean ± SE (standard error). For the treatments, SEM (standard error of the mean)
BES treatment was not included in the statistical analysis
BES 2-bromoethanesulphonate, CHBr₃ Bromoform, SEM Standard error of the mean
^a−dValues within a row with different superscripts differ significantly at P < 0.05 (n = 3)
Contrast: NS Not significant, L Linear response, Q Quadratic response; ^***P < 0.001; ^**P < 0.01, ^*P < 0.05; ^†P < 0.1

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