Table 2. Fermentation parameters of cecal content.

Item	30 d	60 d	120 d	180 d	SEM	P values
pH	—	6.31b	6.42b	6.71a	0.08	<0.01
Ammonia nitrate (mg/g)	5.32a	5.34a	3.34b	1.50c	0.57	<0.01
Volatile fatty acids (mmol/g)	40.03a	34.86ab	33.22b	30.88b	1.82	0.04
Acetate (%)	74.46	78.42	77.42	75.86	1.51	0.37
Propionate (%)	7.14	6.85	6.99	7.45	0.29	0.65
Butyrate (%)	18.40	16.93	16.88	19.64	0.80	0.18
Acetate: Propionate (A: P)	10.59	11.17	11.14	9.81	0.71	0.40

^a-c Values with different superscripts in the same row differ significantly (P<0.05). The data are the means.