In vitro fermentation and production of methane and carbon dioxide from rations containing Moringa oleifera leave silage as a replacement of soybean meal: in vitro assessment

Plant leaf meal of some forage trees such as Moringa oleifera has attracted an increasing interest as a good and cheap source of protein. The present in vitro experiment employed the in vitro wireless gas production (GP) technique to evaluate the inclusion of M. oleifera leaves ensiled for 45 days as a replacement for soybean meal in rations. A control basal ration was formulated to contain 17.5% soybean meal as a source of protein. Soybean meal in the control ration was replaced with silage (MOS) at increasing levels of 0 to 100%. Replacing soybean meal with MOS gradually increased (P < 0.001) GP kinetics (asymptotic GP, rate of GP, and lag time of GP). However, soybean meal replacement decreased (P < 0.001) asymptotic methane (CH(4)) and carbon dioxide (CO(2)) productions, and rate of CH(4) production and increased the lag time of CH(4) and CO(2) production. Gradual increases (P < 0.001) in the digestibility of dry matter, neutral detergent fiber and acid detergent fiber, ruminal bacteria count, fermentation pH, and the concentrations of ruminal total volatile fatty acids, acetate, and propionate were observed with rations containing MOS. Decreases in the digestibility of crude protein, ruminal protozoal count, and the concentrations of ruminal ammonia-N were observed with MOS rations. It is concluded soybean meal can be completely replaced by MOS with desirable effects on ruminal fermentation.