0210 Effects of spices on in vitro enteric methane production

Abstract

This experiment was conducted to study the effects of spices (Rosmarinus officinalis, RO and Allium cepa, OP) on in vitro rumen fermentation, methane production and digestibility of corn silage-based ration. A corn silage-based total mixed ration (TMR; 0.5 g/sample) for dairy cows was treated with each of the spices at doses of 0 (Control), 5 (Low), 10 (Med) and 15% (High) of the TMR or with monensin (1.2 mg/g of TMR). Each mixture was incubated in triplicate in 50 mL of a rumen fluid-buffer inoculum (ratio 1:2) in a 120-mL gas-tight culture bottle at 39°C for 24 h in each of two runs. In vitro DM digestibility (DMD), fermentation parameters, gas and methane production were measured. Data were analyzed using the GLIMMIX procedure of SAS. The high dose of RO decreased DMD and acetate-propionate ratio relative to the Control, whereas, all doses of OP increased DMD and decreased acetate-propionate ratio relative to Control and monensin treatments. Gas volume (mL/g DM) and methane (mL/g DMD) were reduced (P < 0.05) by the High dose of RO and monensin, but not by Low and Med doses, relative to the control. Compared with monensin, adding OP at Low, Med and High doses reduced (P < 0.05; mL/g DMD) the gas volume (158 vs. 140, 136 vs. 110) and methane production (13.48 vs. 9.98, 9.46, and 10.38), respectively. Ruminal pH was increased by monensin and reduced by the High dose of OP. In conclusion, the High rate of Rosmarinus officinalis reduced methane production but decreased TMR digestibility whereas, all doses of of Allium cepa reduced methane production and increased TMR digestibility compared with the control and monensin treatments.