Table 4.

Capacity of strained rumen and cecum liquids from lambs fed wheat- or corn-based diets to degrade readily fermentable substrates in vitro^a

Parameter	Value for indicated diet and substrate								SEM	P valueb
	Wheat				Corn
	Rumen		Cecum		Rumen		Cecum
	Wheat	Corn	Wheat	Corn	Wheat	Corn	Wheat	Corn		D	FC	S
Gas production at 6 h of incubation
Total (μmol/h)	440.40	357.05	382.55	302.66	367.64	264.83	379.96	279.24	45.872	NS	NS	<0.01
Methane (μmol/h)	49.75	37.82	25.90	19.52	36.00	23.57	9.03	6.61	5.344	<0.01	<0.01	<0.05
Methane (%)c	11.18	10.46	6.28	6.10	9.47	8.43	2.60	2.40	0.873	<0.01	<0.01	<0.05
Gas production at 24 h of incubation
Total (μmol/h)	548.47	493.79	465.47	398.28	485.38	397.97	458.20	378.63	40.417	NS	= 0.06	<0.05
Methane (μmol/h)	660.60	645.18	315.22	322.35	567.47	498.07	156.25	164.74	55.042	<0.05	<0.01	NS
Methane (%)c	13.33	13.12	7.62	8.11	12.28	11.73	4.92	5.44	0.001	0.06	<0.01	NS
Hydrogen recovery (%)	68.11	74.10	50.43	53.24	72.57	70.66	45.36	47.67	3.500	NS	<0.01	0.101
VFA production at 24 h of incubation
Total (mM)	122.18	119.47	118.48	111.03	96.96	104.12	96.47	86.59	5.205	<0.01	NS	NS
Acetate (%)d	58.04	54.17	63.10	60.48	58.90	53.03	59.75	59.30	7.455	NS	<0.05	<0.01
Propionate (%)d	23.10	25.18	17.17	16.84	21.37	22.07	25.20	24.95	7.59	NS	NS	NS
Butyrate (%)d	13.70	15.04	15.26	17.34	13.63	19.30	11.25	11.65	9.85	NS	NS	<0.01
Acetate/butyrate ratio	2.76	2.30	4.72	4.09	2.97	2.50	2.38	2.38	0.642	NS	NS	NS
Minor VFA (%)d,e	6.21	6.70	5.39	5.88	5.94	5.91	3.63	3.55	1.124	NS	NS	NS

^aValues represent the means of the results of 6 observations.

^bD, diet; FC, fermentative compartment; S, substrate. The double and triple interactions between D, FC. and S were never significant (P> 0.05). NS, not significant.

^cμmol of CH₄ per μmol of total gas produced.

^d% mM of individual VFA per mM of total VFA produced.

^eMinor VFA are valerate, isovalerate, isobutyrate, and caproate.