In vitro production of methane with increasing levels of corn- or wheat-based dried distillers' grains with solubles in a barley silage-based diet

Abstract

Methane production from wheat- or corn-based dried distillers' grains with solubles (CDDGS, WDDGS) was compared in vitro. Wheat DDGS (49 g fat/kg dry matter [DM]) or CDDGS (115 g fat/kg DM) partially or completely replaced whole-crop barley silage at 200, 400, 600, 800 or 1000 g/kg DM. Production of CH₄ increased linearly and quadraticly (p<0.01) with increasing levels of CDDGS. Cumulative CH₄ production at 24 h was higher (p<0.05) for WDDGS (12.0±0.5 mg/g DM) than CDDGS up to 800 g/kg DM. Molar proportions of propionate in incubation fluid were higher (p<0.05) for CDDG than for WDDGS at 200, 400 and 600 g/kg DM, respectively. In vitro CH₄ production (mg CH₄/g DM; mg CH₄/g digested DM [DMD]) was lower for CDDGS than WDDGS up to 800 g/kg substrate DM. The higher residual oil content in CDDGS compared to WDDGS likely elicited this response.

Keywords:

• In vitro
• dried distillers' grains with solubles
• methane

Acknowledgements

The authors thank R. Chung, D. Vedres and M. Huynh for their assistance. This study was funded by the Feed Opportunities in the Biofuels Industry (FOBI) network of the AAFC Agricultural Bioproducts Innovation programme, and from the Norwegian–Canadian BILAT project.