Effects of urea plus nitrate pretreated rice straw and corn oil supplementation on fiber digestibility, nitrogen balance, rumen fermentation, microbiota and methane emissions in goats

Table 4 Effect of urea plus nitrate pretreated rice straw (UN) and combination of UN and corn oil supplementation (UNCO) on dissolved gases and fermentation end products in the rumen of goats

Items	Treatment			Time after morning feeding			SEM	P - value
Items	Control	UN	UNCO	0 h	2.5 h	6 h	SEM	Treatment	Time	Treatment × Time
pH	6.34^b	6.47^a	6.33^b	6.51^a	6.30^b	6.34^b	0.072	< 0.001	< 0.001	0.42
NH₄⁺, mmol/L	8.26^b	10.8^a	11.2^a	10.9	10.8	8.6	1.31	0.02	0.06	0.58
Dissolved gases
Dissolved hydrogen, μmol/L	0.57^a	0.44^b	0.46^b	0.30^c	0.71^a	0.46^b	0.038	< 0.001	< 0.001	0.61
Dissolved methane, mmol/L	1.31^a	1.23^a	0.99^b	1.55^a	1.01^b	0.96^b	0.067	< 0.001	< 0.001	0.18
Total VFA, mmol/L	82.3	82.1	77.5	77.4^b	85.6^a	79.0^ab	3.73	0.15	< 0.001	0.99
Molar proportion of individual VFA, mol/100 mol
Acetate	70.1	70.5	69.2	69.7	70.4	69.7	0.89	0.19	0.57	0.97
Propionate	19.3	20.6	19.9	19.4	20.1	20.4	0.92	0.12	0.21	0.99
Butyrate	7.52^a	6.15^b	8.10^a	7.50	6.91	7.36	0.472	< 0.001	0.28	0.72
Iso-butyrate	1.05^a	0.90^b	0.91^b	1.16^a	0.85^b	0.84^b	0.058	< 0.001	< 0.001	0.77
Valerate	0.65^a	0.57^b	0.65^a	0.62^ab	0.67^a	0.59^b	0.029	0.02	0.03	0.85
Iso-valerate	1.40	1.21	1.31	1.66^a	1.13^b	1.14^b	0.102	0.09	< 0.001	0.96
Acetate/Propionate ratio	3.83	3.50	3.66	3.73	3.67	3.59	0.20	0.06	0.58	0.99
(Acetate + butyrate)/Propionate ratio	4.23^a	3.82^b	4.09^ab	4.13	4.03	3.97	0.141	0.01	0.52	0.99

^a-cMeans with different superscripts within a row and heading are significantly different (P ≤ 0.05)

ISSN: 2049-1891