methane, ruminants, tropical grasses, forage shrubs
Objective: To evaluate total in vitro gas and methane (CH 4 ) production in different mixtures of Hyparrhenia ruffa (Hr) and Leucaena leucocephala (Ll).
Design/methodology/approach: In airtight biodigesters with 200 mL of culture medium, 20 g of the following treatments were incubated by triplicate: T1: 100 % Hr, T2: 80 % Hr + 20 % Ll, T3: 60 % Hr + 40 % Ll, T4: 40 % Hr + 60 % Ll; these were inoculated with 20 mL of fresh rumen fluid and incubated at 38 ± 0.5 °C for 24, 48, 72 and 96 h. The total gas and CH 4 production were assessed; the data were analyzed in a completely randomized design.
Results: The addition of 20 %, 40 % and 60 % Ll in mixture with Hr decreased theneutral detergent fiber (NDF), acid detergent fiber (ADF), total gas and CH 4 production, while the crude protein content increased.
Study limitations/implications: In vivo studies are required / by including amounts higher than 20 % Ll may improve energy utilization efficiency.
Findings/conclusions: Adding more than 20 % L. leucocephala in a mixture with H. ruffa decreases total gas and CH 4 production.