Table 2.

Effects of acetogen, S. cerevisiae fermentation product, co-addition of acetogen and yeast culture on methane emission and rumen fermentation parameters

Parameter	Control	TWA4	XP	TWA4XP	SEM	P-value
						TWA4×XP	TWA4			XP
							Main	+XP	−XP	Main	+TWA4	−TWA4
CH4 (ml/g substrate)
6 h	7.76±0.15c	9.89±0.71b	8.20±0.18c	16.06±0.42a	0.43	<0.01	<0.01	<0.01	<0.01	<0.01	<0.01	0.48
12 h	27.69±0.91b	28.30±2.85b	24.76±0.20b	38.36±0.10a	1.50	<0.01	<0.01	<0.01	0.78	<0.05	<0.01	0.2
24 h	53.97±0.75b	48.55±0.22b	49.58±2.88b	64.76±1.46a	1.66	<0.01	<0.05	<0.01	0.05	<0.01	<0.01	0.1
48 h	60.19±0.20b	59.88±0.61b	59.23±0.83b	88.26±1.03a	0.74	<0.01	<0.01	<0.01	0.77	<0.01	<0.01	0.38
CH4 (% of GP)
6 h	17.12±0.17c	20.76±0.003b	17.70±1.47c	27.20±0.73a	0.77	<0.01	<0.01	<0.01	<0.05	<0.01	<0.01	0.59
12 h	31.44±0.75ab	31.40±2.93ab	29.12±0.28b	35.35±0.04a	1.52	0.07	0.08			0.61
24 h	40.25±0.57ab	36.11±0.27c	38.30±1.74bc	39.84±1.03ab	1.03	<0.05	0.24	0.32	<0.05	0.42	<0.05	0.22
48 h	35.51±0.19b	35.57±0.31b	36.00±0.22b	43.74±0.47b	0.32	<0.01	<0.01	<0.01	0.9	<0.01	<0.01	0.31
VFA (mmol/L)
Total	99.46±0.15c	100.05±0.49c	103.16±0.76b	114.94±1.08a	0.71	<0.01	<0.01	<0.01	0.58	<0.01	<0.01	<0.01
Acetate (A)	61.40±0.30c	62.15±0.17c	64.28±0.41b	70.82±1.85a	0.6	<0.01	<0.01	<0.01	0.39	<0.01	<0.01	<0.01
Propionate (P)	23.11±0.15b	23.14±0.28b	23.63±0.30b	27.18±0.23a	0.25	<0.01	<0.01	<0.01	0.95	<0.01	<0.01	0.18
Butyrate	9.46±0.09c	9.47±0.08c	10.04±0.15b	11.07±0.28a	0.17	<0.05	<0.05	<0.01	0.96	<0.01	<0.01	<0.05
A:P*	2.66±0.03ab	2.69±0.03ab	2.72±0.03a	2.61±0.03b	0.028	<0.05	0.17	<0.05	0.46	0.76	0.07	0.14
DMD (%)	62.34±0.26	61.39±2.33	59.88±2.42	62.59±1.67	1.88	0.65	0.74			0.36

GP: gas production; VFA: volatile fatty acids; DMD: dry matter degradation; TWA4: acetogen; XP: Saccharomyces cerevisiae fermentation product; TWA4XP: co-addition of acetogen and yeast culture; SEM: pooled standard error of the mean (n=3). For the P-value, ×: interaction; +: with supplementation; −: without supplementation. Data, shown as mean±standard error (n=3), within a row with different superscripts differ significantly (P<0.05).^* Data were expressed as proportions