Effect of foliage from multi-purpose trees and a leguminous crop residue on in vitro methanogenesis and ruminal N use

The effects of supplementing a low-quality tropical grass (Brachiaria humidicola CIAT 6133) with foliage from multi-purpose trees (MPTs; Acacia angustissima ILRI accessions 459 and 15132; Sesbania sesban ILRI 10865 and 15019, Samanea saman ILRI 14884) and a leguminous food-feed crop (Cajanus cajan ILRI 16555) on methanogenesis and N use were measured with rumen simulation technique. All supplements improved the supply of fermentable nutrients, particularly of degradable N, and improved N utilization. One accession of A. angustissima (459) and one of S. sesban (10865) were effective in limiting methanogenesis. Effects of C. cajan and S. sesban (10865) on N turnover and total methane were additive when supplemented together. Thus, this combination presents a promising choice to improve low-quality tropical diets at a limited methane emission.