In vitro green house gas production and organic matter digestion effected by natural tannin sources, and ground maize added to substrate of mom grass (Hymenachne acutigluma)

Abstract

Two in vitro experiments were done to evaluate the green house gas production and organic matter digestibility. In the first experiment thirteen plant varieties were used for analysis of nutrients and condensed tannin content, then for gas production. The second experiment was a completely randomized design with 5 treatments and 3 replications. The treatments were levels of ground maize at 0, 5, 10, 15 and 20% (DM) added to the main substrate being Mom grass (Hymenachne acutigluma) corresponding to the CM0, GM5, GM 10, GM l5 and GM20 treatments. The results showed that in Exp l, condensed tannin contents were high in P. guajava leaves, rnangostine peel and S. sanrarangense leaves (11.8, 10.4 and 9.72%, respectively). They gave a lower CH4 production (less than 0.10 ml/g DOM) compared to others. While Arachis pintoi, P. purpureum and Brachiaria mutica, which were lower in condensed tannin content (less than 2.10%), resulted in and produced higher Ch4 production (rnorelhan 8.85 ml/g DOM). In the Exp 2, the total gas, CH4 and CO2 production (ml/g OM) at 96h were significantly (P<0.05) different among the treatments and the CH4 production of GM l5 treatment was significantly higher (P<0.05) than those of the GM0, GM5 and GMl0 treatment. Similarly, the significantly higher (P<0.05) DOM (digested organic matter) values were found for the GM15 and M20 treatment as compared to CMO and GM10 treatments. The conclusion was that naturally condensed tannin sources from the plants (more than 9.5%) gave a lower in vitro CH4 production, and no reduction of CH4 elfected by increasing supplementation of ground maize to grass was found in the present experiment.