Ruminal digestibility, microbial count, volatile fatty acids and gas kinetics of alternative forage sources for arid and semi-arid areas as in vitro

Figures & data

Table 1. Nutrient compositions and RFV of different alternative forages (n = 6).

	Alfalfa	A. patula	P. lanceolata	SD	SEM	p value
TCT	0.37^b	0.46^b	1.38^a	0.48	0.16	<.001
CP	19.18^a	14.64^b	10.74^c	3.70	1.23	<.001
EE	1.54^b	1.40^b	1.95^a	0.26	0.08	≤.001
Ash	8.45^c	14.56^a	11.59^b	2.65	0.88	<.001
CF	30.66^a	23.99^b	24.71^b	3.23	1.07	<.001
aNDFom	38.01^b	41.04^a	37.29^b	1.81	0.60	≤.001
ADFom	32.78^a	27.92^b	31.88^a	3.64	1.21	≤.001
HC	5.22^b	13.12^a	5.41^c	5.31	1.77	<.001
ADL	6.48^b	4.86^c	10.20^a	4.79	1.69	<.001
RFV	155.06	152.22	159.01	3.21	1.07	.492

SD: Standard deviation of means; SEM: Standard error of means; TCT: total condensed tannin; CP: crude protein; EE: diethyl ether extract; CF: crude fibre; aNDFom: neutral detergent fibre assayed with a heat stable amylase and expressed exclusive of residual ash; ADFom: acid detergent fibre expressed exclusive of residual ash; HC: hemicellulose (aNDFom-ADFom); ADL: acid detergent lignin determined by solubilisation of cellulose with sulphuric acid; RFV: relative feed value.

^a,b,cMeans within the same line with differing superscripts are significantly different.

Table 2. In vitro gas kinetics and cumulative gas productions of different alternative forage (n = 6).

	Alfalfa	A. patula	P. lanceolata	SD	SEM	p value
Gas kinetics
cgas	0.05	0.05	0.05	0.02	0.01	.788
bgas	52.79	55.75	52.22	2.44	0.99	.372
(a + b)gas	53.26	56.95	52.17	2.96	1.20	.280
Cumulative gas production
3 h	9.83	9.66	10.58	1.60	0.32	.212
6 h	20.00	20.16	20.75	2.01	0.41	.732
12 h	33.66	33.00	33.25	2.94	0.60	.930
24 h	41.33	41.16	42.00	3.49	0.71	.878
48 h	56.66	54.33	53.16	2.83	0.81	.233
72 h	57.33	55.33	55.16	3.30	0.95	.674
96 h	57.33	56.33	55.83	3.72	1.07	.874

SD: Standard deviation of Means; SEM: Standard Error of Means; c_gas=gas production rate (%, 0.2 g DM); b_gas=gas production from insoluble fraction (ml/0.2 g DM); (a + b)_gas=potential gas production (ml/0.2 g DM).

Table 3. Estimated gas production parameters, ruminal ammonia-N concentration and in vitro ruminal methane production of different alternative forages (n = 6).

	Alfalfa	A. patula	P. lanceolata	SD	SEM	p value
ME	7.91	7.85	7.96	0.47	0.09	.915
NEL	4.50	4.48	4.49	0.39	0.08	.996
OMD	51.33	51.19	51.87	2.96	0.60	.886
Ammonia-N	47.85^a	48.02^a	36.50^b	6.23	1.80	<.001
Methane	19.23^ab	22.06^a	16.69^b	2.84	0.81	.007

SD: Standard deviation of Means; SEM: Standard Error of Means; ME: estimated metabolisable energy (MJ/kg DM); NE_L: estimated net energy lactation (MJ/kg DM); OMD: estimated organic matter digestibility (%); Ammonia-N: ammonia-N concentration of rumen fluid at 24 h (mg N/L); Methane: it expresses methane production as percent in total gas produced at 24 h.

^a,bMeans within the same line with differing superscripts are significantly different.

Table 4. Effects of different forage sources on total VFAs (mmol/L), molar proportions of individual VFAs (% of total VFAs), bacteria (×10⁸/mL) and protozoa numbers (×10⁴/mL) in rumen fluid (n = 6).

Items	Alfalfa	A. patula	P. lanceolata	SD	SEM	p value
Total VFAs	110.36	111.78	113.09	40.20	11.60	.602
Acetic acid (A)	47.40	53.30	60.57	8.49	2.45	.062
Propionic acid (P)	28.38^a	19.51^b	20.75^b	3.80	1.09	<.001
Butyric acid (B)	15.46	18.97	12.66	4.97	1.43	.205
Other volatile acids	8.75	8.20	6.01	2.01	0.58	.088
(A + B)/P	2.22^b	3.71^a	3.54^a	0.66	0.19	<.001
Total bacteria	2.52	2.96	2.45	0.40	0.11	.197
Total ciliate protozoa	42.92	43.08	42.59	8.86	2.55	.419
Isotricha spp.	0.26^a	0.20^a	0.16^b	0.06	0.02	.049
Dasytricha sp.	0.62	0.58	0.57	0.14	0.04	.913
Diplodiniinae	10.63	12.20	16.00	4.19	1.21	.149
Entodiniinae	31.41	30.10	25.86	9.13	2.63	.213

SD: Standard deviation of means; SEM: Standard error of means; Total VFAs: Acetic + propionic + butyric + other volatile acids. Other volatile acids: Iso-butyric acid + Valeric acid + Iso-valeric acid.

^a,bMeans within the same line with differing superscripts are significantly different.