81 Effects of engineered biocarbons on total gas and methane production, rumen fermentation and microbial protein synthesis in a semi continuous fermentation system (RUSITEC)

Abstract

Abstract This study investigated the effects of engineered biocarbon on nutrient digestibility, rumen fermentation, total gas and methane (CH4) emissions, and microbial protein synthesis in a rumen simulation technique (RUSITEC) fed a barley silage-based TMR. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal and 3% minerals. Three pine-based biocarbon products CP016, CP024 and CP028. were added at 2% of substrate DM. Biocarbons differed in bulk density, surface area, pore volume, pH, but had similar chemical compositions. Treatments were assigned to sixteen vessels (n = 4/treatment) in two RUSITEC apparatuses in a randomized block design. The experiment period was 17 d, with a 10-d adaptation and 7-d sample collection period. Data were analyzed using the PROC MIXED in SAS, with treatment (T), day (D) and TxD interactions as fixed effects and RUSITEC apparatus and fermenters as random effects. Compared to the control, biocarbon did not affect total gas (P = 0.98), the amount of CH4 produced per unit of DM incubated (P = 0.48) or per unit of DM digested (P = 0.27). Biocarbon treatments averaged 6.5 g of CH4 /g DM incubated and 9.06 g CH4 /g DM digested as compared to 7.1 g of CH4 /g DM incubated and 10.46 g CH4 / g DM digested in the control, respectively. Biocarbon CP024 had the greatest numerical reduction, followed by CP028 then CP016 in all CH4 associated parameters. Biocarbon addition did not affect the disappearance of DM (P = 0.63), OM (P = 0.34), CP (P = 0.48), NDF (P = 0.12), or VFA (P = 0.65) and ammonia N levels (P = 0.99) and protozoal counts (P = 0.72). The amount of bacterial nitrogen (mg/d) associated with feed particles increased (P < 0.003), suggesting that biocarbon may have enhanced colonization. In conclusion, engineered biocarbon did not reduce CH4 emissions in the RUSITEC.