Effect of engineered biocarbon on rumen fermentation, microbial protein synthesis, and methane production in an artificial rumen (RUSITEC) fed a high forage diet1

Abstract

The objective of this study was to investigate the effects of adding engineered biocarbon to a high-forage diet on ruminal fermentation, nutrient digestion, and enteric methane (CH4) production in a semi-continuous culture artificial rumen system (RUSITEC). The experiment was a completely randomized block design with four treatments assigned to sixteen fermentation vessels (four/treatment) in two RUSITEC apparatuses. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal, and 3% supplement (DM basis) with biocarbon added at 0, 0.5, 1, and 2% of substrate DM. The study period was 17 d, with a 10-d adaptation and 7-d sample collection period. Increasing biocarbon linearly increased (P < 0.05) disappearance of DM, OM, CP, ADF and NDF. Compared to control, increasing biocarbon enhanced (P < 0.01) production of total VFA, acetate, propionate, branch-chained VFAs, and tended to increase (P = 0.06) NH3-N. Microbial protein synthesis linearly increased (P = 0.01) with increasing biocarbon. Addition of biocarbon reduced overall CH4 production compared with the control (P ≤ 0.05). There were no differences (P > 0.05) in production of total gas, large or small peptides, or in the number of protozoa as a result of addition of biocarbon to the diet. Addition of biocarbon to a forage diet increased DM digestibility by up to 2%, while lowering enteric CH4 production and enhancing microbial protein synthesis in in vitro semi- continuous culture fermenters.

The effect of total and individual alfalfa saponins on rumen methane production

“…It is worth mentioning that when protozoa are partially inhibited by saponin-rich sources, predation intensity is reduced; in consequence, the intensity of the predation of rumen bacteria by protozoa decreases. 1,2 This is in line with our results, which show higher bacterial counts with increased saponin levels. The reason for this might be that the saponins found in this alfalfa variety have a stimulating effect on the growth of some cellulolytic bacteria.…”

“…Methane emission is a key factor in climate change, as it exerts a global warming potential 28 times greater than that of CO 2 . 1 Furthermore, methane produced by ruminant digestion results in significant dietary energy loss. 2 Developing strategies to mitigate methane production in dairy cows is a challenge in both environmental and economic terms.…”

Use of biochar as feed supplements for animal farming

“…McFarlane et al (2017) reported that 81 g/kg dry matter of plant-based biochar reduced the digestibility of forage and increased volatile fatty acid production. Saleem et al (2018) found that pine-based biochar could improve in vitro ruminal fermentation, nutrient disappearance, and microbial protein synthesis, and reduce enteric methane production. Leng et al (2012) reported that cattle weight increased by 25% when 0.6% rice husk-based biochar was added to the diet, when compared to the control diet without biochar.…”

“…Since 2010, biochar has increasingly been used as a feed additive in animal husbandry (O'Toole et al, 2016). As shown in Table 1, biochar used as a feed supplement is commonly made from biomass such as rice husks (Leng et al, 2012;Phongpanith, Inthapanya, & Preston, 2013), woody green waste (Prasai et al, 2016), pine wood chips (Saleem et al, 2018) and jarrah wood (Joseph et al, 2015).…”

“…Phanthavong, Viengsakoun, Sangkhom, and Preston (2015) showed in an in vitro rumen incubation experiment that biochar could reduce methane production by between 0.5% and 1.7% when compared to a control without biochar after 24 h incubation. Biochar can improve in vitro ruminal fermentation, nutrient disappearance and microbial protein synthesis, and reduce enteric methane production (Saleem et al, 2018).…”