Effect of Cinnamon Bark Meal (Cinnamomun burmanni Ness ex Bl) on in Vitro Methane Production and Rumen Methanogens Diversity

Plant secondary metabolites such as cinnamaldehyde have been used to manipulate methane production in the rumen. The research aimed to investigate the effect of cinnamon bark meal as cinnamaldehyde source on methane production and methanogen diversity in the rumen. Substrate of fermentation consist of Pennisetum purpureum, wheat pollard and soybean meal. Cinnamon bark meal was added into feed sample equal to cinnamaldehyde level as much as 200, 400, 600, 800 mg based on dry matter (DM). Parameters recorded were dry matter digestibility (DMD), organic matter digestibility (OMD), methane production, number of protozoa and communities of methanogen. Fermentation parameters were measured by incubating the sample in a rumen liquor buffer that was taken from a rumen fistulated Bali cattle. In vitro gas production was analyzed using Menke and Steingass gas production technique. Methanogenic communities were observed using Terminal Restriction Fragment Length Polymorphism (T-RFLP) technique. The bacterial diversity (H' index) and evenness (E index) were calculated from the peak value. Results showed that there was no significant (P>0.05) different among treatments on IVDMD, IVOMD, methane production and number of protozoa. Based on T-RFLP, methanogenic archaea diversity was not affected by the diet. This study shows that addition of cinnamon bark meal as cinnamaldehyde source may not viable CH4 mitigation strategies to reduce methanogenic activity in the rumen.