In Vitro Rumen Fermentation Characteristics of Some Naturally Occurring and Synthetic Sugars

Figures & data

Table 1. In vitro gas production (mL/g of dry matter) obtained after 3, 9 and 24 h of fermentation of different sugars incubated with different sources of inoculum.

	Incubation time
	3 h			9 h			24 h
	Caec	RuNoAd	RuAd	Caec	RuNoAd	RuAd	Caec	RuNoAd	RuAd
Glucose	58.29	110.19	105.66	280.26	277.97	274.84	323.64	339.25	333.08
Fructose	13.03	104.94	98.62	211.12	280.11	276.10	302.48	340.30	342.84
Xylose	10.92	38.29	38.42	183.00	212.14	223.86	308.16	330.38	339.25
Galactose	35.95	43.04	42.46	249.16	250.50	256.02	314.13	333.97	345.44
Arabinose	13.39	50.05	51.50	214.93	240.32	234.61	319.97	340.12	330.88
Mannitol	3.02	21.11	22.38	36.06	146.71	151.00	228.02	298.45	293.43
Sucrose	17.91	105.76	116.27	228.07	273.61	263.68	297.35	336.83	324.65
Lactose	56.70	34.40	31.68	254.67	211.22	224.77	298.53	320.05	311.92
Lactulose	8.48	19.18	18.59	78.27	109.42	134.37	276.20	315.86	340.48
Sucralose	0.23	-3.26	-3.16	0.24	-4.42	-4.31	-1.32	-4.30	-3.98
SEM		16.56			90.32			77.19
Significance
Inoculum		0.01			0.01			0.01
Sugars		0.01			0.01			0.01
Interaction		0.01			0.01			0.01

Caec, caecal inoculum; RuAd, ruminal inoculum from animals adapted to feed with sugars; RuNoAD, ruminal inoculum from animals not adapted to feed with sugars.

Table 2. Production of volatile fatty acids (VFA, mmol/L) and their molar percentages (%:mmol/100 mmol of total VFA) after 24 h in vitro fermentation of different sugars with different sources of inoculum.

	Inoculum	Sugars										SEM	Significance
		Glucose	Fructose	Xylose	Galactose	Arabinose	Mannitol	Sucrose	Lactose	Lactulose	Sucralose		Inoculum	Substrate	Interaction
VFA, mmol/L	Caec	57.82	62.01	48.83	58.43	54.41	54.98	59.87	57.78	59.67	7.77
	RuAd	40.42	41.57	47.24	44.61	47.61	39.88	39.78	42.56	37.84	-2.72	10.18	0.01	0.01	0.01
	RuNoAd	42.94	43.77	47.16	43.70	50.07	41.02	39.88	39.54	38.23	-2.72
Acetate, %	Caec	64.01	61.87	64.52	65.62	60.22	61.35	64.01	71.28	69.11	53.79
	RuAd	47.44	47.29	52.92	50.14	53.09	44.28	47.26	53.84	54.99	61.23	0.13	0.01	0.01	0.01
	RuNoAd	49.38	49.09	55.68	52.25	54.66	43.77	48.48	55.04	57.49	64.59
Propionate, %	Caec	19.16	25.37	21.16	18.95	23.46	26.58	20.63	15.87	19.98	24.16
	RuAd	27.02	27.43	29.64	27.44	28.87	33.00	27.55	28.95	23.17	17.57	0.16	0.01	0.01	0.01
	RuNoAd	28.48	29.55	28.35	27.99	28.37	33.48	28.58	26.96	22.99	14.76
Butyrate, %	Caec	12.24	8.28	10.00	11.01	11.41	7.02	10.92	8.72	6.82	11.22
	RuAd	20.54	20.26	12.73	17.07	12.77	16.98	20.22	12.25	17.16	12.73	0.20	0.01	0.01	0.01
	RuNoAd	16.35	15.55	10.45	14.02	11.00	16.25	17.32	12.56	14.60	11.31
Valerate, %	Caec	1.96	2.04	1.90	1.93	2.09	2.06	1.95	1.68	1.83	4.20
	RuAd	2.99	3.10	2.54	3.00	2.81	3.76	2.99	2.95	2.75	4.34	0.03	0.01	0.01	0.01
	RuNoAd	2.77	2.79	2.58	2.82	2.79	3.57	2.71	2.79	2.54	3.98
Isobutyrate, %	Caec	1.12	0.96	1.05	1.05	1.19	1.15	1.02	1.07	0.91	2.41
	RuAd	0.59	0.55	0.74	0.78	0.87	0.55	0.58	0.60	0.60	1.19	0.006	0.01	0.01	0.01
	RuNoAd	1.04	1.01	1.06	1.03	1.13	0.94	0.99	0.89	0.81	1.59
IsoValerate, %	Caec	1.50	1.48	1.37	1.45	1.61	1.85	1.47	1.39	1.36	4.21
	RuAd	1.42	1.37	1.41	1.57	1.59	1.42	1.40	1.41	1.33	2.94	0.007	0.01	0.01	0.01
	RuNoAd	1.99	2.00	1.88	1.88	2.05	1.99	1.92	1.76	1.57	3.77
NGR	Caec	4.62	3.09	3.99	4.62	3.54	2.84	4.16	5.59	4.14	3.16
	RuAd	3.28	3.20	2.64	3.07	2.72	2.37	3.18	2.71	3.85	4.93	0.029	0.01	0.01	0.01
	RuNoAd	2.88	2.71	2.70	2.87	2.70	2.28	2.91	2.97	3.77	5.91

Caec, caecal inoculums; RuAd, ruminal inoculum from animals adapted to feed with sugars; RuNoAD, ruminal inoculum from animals not adapted to feed with sugars; VFA, volatile fatty acids produced after 24h fermentation (mmol/L); NGR, non glucogenic ratio- (acetate+2 butyrate)/propionate.

Table 3. Curve fit parameters of gas production curves of different sugars incubated with buffered rumen fluid for 72 h.

	Potential gas production, mL/g DM	Fermentation rate, %/h
Glucose	372.03	10.42
Fructose	368.83	10.57
Xylose	378.07	6.79
Galactose	374.73	7.22
Arabinose	386.20	7.18
Mannitol	385.40	4.63
Sucrose	368.43	9.83
Lactose	379.03	6.08
Lactulose	436.30	3.47
SEM	76.11	0.00000804
Significance
Sugars	0.01	0.01

DM, dry matter.