Abstract
This study investigated the effects of post-pyrolysis treated biochar on nutrient disappearance, total gas and methane (CH4) production, rumen fermentation and microbial protein synthesis in an artificial rumen system (RUSITEC) fed a barley silage-based diet. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal and 3% mineral/vitamin supplement (DM basis). Three spruced-based biochars, treated post-pyrolysis with either zinc chloride, hydrochloric acid/nitric acid mixture or sulfuric acid were added at 2.0% of substrate DM. In a randomized complete block design, treatments were assigned to sixteen vessels (n = 4/treatment) in two RUSITEC systems. The experiment was conducted over 15 d, with 8 d of adaptation and 7 d of sampling. Nutrient disappearance of dry matter (DM), organic matter (OM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) was determined after 48 h of incubation from d 9 to 12, and microbial protein synthesis was measured from d 13–15. Data were analyzed using PROC MIXED in SAS, with the fixed effect of treatment and random effect of RUSITEC system and vessel. Biochar inclusion did not affect disappearance of DM (P = 0.49), OM (P = 0.60), CP (P = 0.14), NDF (P = 0.48), ADF (P = 0.11) or starch (P = 0.58). Biochar also had no effect on total gas production (P = 0.31) or CH4 produced expressed as a % of total gas production (P = 0.06), mg/d (P = 0.70), mg/g of DM incubated (P = 0.74), or mg/g of DM digested (P = 0.64). No effect on total VFA (P = 0.56) or NH3-N (P = 0.20) production were observed. Neither microbial protein synthesis nor total protozoa count were affected by biochar addition (P > 0.05). In conclusion, biochar inclusion in a silage-based diet did not exhibit the potential to mitigate CH4 emissions or improve digestion in a RUSITEC system.
Control tools to selectively produce purple bacteria for microbial protein in raceway reactors
