Chemical composition, organic matter digestibility and gas production of nine legume grains

Nine legume grains (Pisum sativum, Cicer arietinum, Vicia sativa, Vicia faba, Lathyrus ochrus, Lathyrus cícera, Lupinus angustifolius and Lupinus luteus) were studied with respect to their chemical composition, organic matter digestibility (OMD) and digestible energy (DE) using rams in metabolic cages. Gas production by grains was evaluated using rumen inoculum. The majority of these legume grains showed values of: crude protein (CP) — 21 to 24%, ether extract (EE) — 1.5 to 5%, neutral detergent fibre (NDF) — 15 to 22%, acid detergent fibre (ADF) — 6 to 13%, starch — 30 to 40%, OMD — 90 to 92%, DE — 16 to 17 MJ kg−1 dry matter (DM) and gas production (48 h) of 110 to 145 ml g−1 DM. Lupinus however showed much higher values of CP (29.1% and 34.4%), NDF (26.9% and 28.6%), ADF (22.9% and 24.6%), EE (5.4% and 7.2%) and lower values of starch about 0.8%, OMD (83.6% and 86.0%) and gas production (95.9 and 104.6 ml g−1 DM). Gas production (48 h) was negatively correlated to CP (r = −0.74; P < 0.05), NDF (r = −0.93; P < 0.001), ADF (r = −0.78; P < 0.01), positively with starch (r = 0.70; P < 0.05) and positively with OMD (r = 0.68; P < 0.05). Gas production in this type of feed was not shown to be a good criterion for assessing their OMD.