Methane Production and Fermentation Pattern of Local Sheep Rumen Given Complete Feed with Indigofera sp. and Mung Bean Sprout Waste Using RUSITEC

Abstract

Methane (CH4) enteric, naturally is fermentation metabolic from rumen microorganism which is in gas form and most of it will be excreted through the mouth as an eructation process. Indigofera sp. is a legume shrub which has high nutrient content; 27.97% crude protein, 19-50% NDF (neutral detergent fiber), 15% crude fiber, 0.22% calcium, 0.19% phosphor, and organic matter digestibility (in vitro) was 56-72%. Mung bean sprout waste is part of bean sprouts which is not consumed by humans, it contain green husk of bean and usually mixed by chunks of tail and head of sprouts that are no longer intact. Mung bean sprout waste contain 13-14% crude protein, crude fiber 49.44%, and 64.65% TDN. Indigofera sp. and mung bean sprout waste are potential as feed sources. Both of them could be used in ruminant ration as high protein and energy contribution. Ruminant methane production is highly influenced by nutrient composition and chemical form of ration, so any information regarding methane production determined by forms and compositions of ration are precious. This study aimed to identify the effect of complete feed for local sheep containing 30% Indigofera sp. or 30% mung bean sprout waste on methane production and obtained the rumen fermentation pattern using RUSITEC. The measurement of methane production can be performed using experimental animals (in vivo), in vitro, and semi in vitro–better known as rumen simulation technique (RUSITEC) which is a more complex rumen simulator than other in vitro analysis. Methane concentration was measured using methane analyzer. The rations were composed iso-calories and pelleted, they contained 30% Indigofera sp. and 70% concentrate (IS) or 30% mung bean sprout waste and 70% concentrate (LT). The rumen fluid were obtained from eight adult local sheep. They were kept for three months, four of them were fed IS and the other four were LT. Incubated ration in RUSITEC were same as fed for the sheep, it expected that obtained the same fermentation conditions between RUSITEC and sheep rumen. RUSITEC Analysis was conducted for eleven days, consisted of five days for adaptation period and six days (sixth to eleventh) for observation period. Responses observed were total gas production, percentage and methane production, pH, ammonia concentration, dry matter and organic matter degradation. The fermentation of responses by time were presented descriptively. Averages of responses were analyzed using student t-test. The patterns of total gas production, percentage and methane production, pH, ammonia concentration, dry matter and organic matter degradation were fluctuation by observation time. Total gas production of IS was significantly (P < 0.05) higher (1995.81 mL/day) than LT (1682.49 mL/day). Methane production of IS ration (163.58 ml/day equivalent to 9.59 mL/g incubated dry matter) was not significantly different with LT (141.43 ml/day equivalent to 8.23 mL/g incubated dry matter). The pH Values, ammonia concentration, dry matter and organic matter degradation of IS and LT were 6.78 and 6.91; 7.59 mM and 4.85 mM; 53.56% and 43.25%; 57.52% and 45.96% respectively. The pH value and ammonia concentration were not significant different in all treatments, however dry and organic matter degradation were significantly (P < 0.05) higher in IS compared to LT. Value of pH during running with RUSITEC was in normal range (6.54-7.05). In both groups of incubation rations, all responses were fluctuation during fermentation. The high degradation of dry matter and organic matter of IS had significant effect on total gas production but did not enough affect the methane production.