Table 5.

Effect of metabolites from tropical trees on molar proportions of volatile fatty acids and CH₄ production in the rumen.

Diet/Conditions and Quantity of Substrate	Source of Metabolites	Dose	Molar Proportion			CH4	References
			Acetate	Propionate	Butyrate	mmoL/day
RUSITEC (14 g/day of mix grass: legume, 80: 20 in fermenters).	Samanea saman 14884	ND	63	27	7	3.61	[73]
	Acacia angustissima 459	ND	64	26	7	2.02
	Sesbania sesban 10865	ND	63	28	7	1.55
Basal diet	Sheep fed with concentrates	0:3	73	19	7	1.85	[74]
B. brizantha: Cratylia argentea		1:3	72	21	7	1.81
		2:1	68	23	7	1.73
Basal diet	Sheep fed with concentrates plus S. saponaria (7.71 g crude saponin/lamb/day) in each proportion	0:3	72	21	6	1.63
Cratylia argentea: B. brizantha		1:3	70	23	6	1.68
		2:1	69	23	7	1.64
Isoenergetic and isoproteic balanced diets	Neomillspaughia emargiata Tabernaemontana amygdalifolia Caesalpinia gaumeri Piscidia piscipula Leucaena leucocephala Havardia albicans	1:3	61	25.8	13.92	1.73	[75]
Water flour (80%) Water straw (20%)	Sapindus mukurossi Water extract	20 g/100 mL of solvent	53.12	34.20	12.67	22.68	[72]
	Control	0	60.26	21.71	17.97
	Sapindus mukurossi Methanol extract	20 g/100 mL of solvent	61.21	27.24	11.56	0
	Control	0	61.48	27.4	11.21
	Sapindus mukurossi Ethanol extract	20 g/100 mL of solvent	60.60	29.11	10.29	11.48
	Control	0	61.10	29.92	8.97
	Control	0	3.92	0.94	0.30	2.35
HFD 80:20	Myristica fragrans	1 mL extract/100 mL	2.90	0.76	0.31	1.97	[76]
	Control	0	4.09	1.13	0.38	2.57
LFD 20:80	Myristica fragrans	1 mL extract/100 mL	3.06	0.96	0.41	2.01

RUSITEC: Ruminal simulation technique system; CH₄: methane; ND: not determinate; HFD: high fiber diet; LFD: low fiber diet.