Effectiveness of xylanase and Saccharomyces cerevisiae as feed additives on gas emissions from agricultural calf farms

Abstract

The aim of the present study was to evaluate the potential of supplementing calves’ diets with exogenous enzymes (xylanase; XYL) and yeast (Saccharomyces cerevisiae [SC]) on the sustainable control of methane (CH4) and carbon dioxide (CO2) productions in agricultural calves farming. Three different levels of supplemented diets of XYL (0, 3 and 6 mg/g of dry matter (DM)), SC (0, 2 and 4 mg/g of DM) and mixture of XYL and SC (0, 2 mL XYL þ 2 mg SC, 6 mL XYL þ 4 mg SC/g of DM) were tested. Asymptotic gas production (GP) consistently decreased by each of the additives with the lowest value at the high dose of XYL þ SC mixture (P < 0.05) compared with the control and the low dose of XYL þ SC mixture. Methane production was reduced by additives inclusion (P < 0.05) when compared with the control treatment with no additive. Xylanase þ SC at all doses increased CO2 production (P < 0.05) whereas the high dose had the most statistically significant (P < 0.05) reduction in GP and CH4 production compared with control, XYL and SC additives at different doses. Interaction between additive and rumen liquor was observed for rate of GP (P ¼ 0.027) and initial delay before GP (P < 0.001). Inclusion of XYL, SC, and XYL þ SC mixture had less asymptotic GP while XYL þ SC mixture had the lowest initial delay (39%) before GP began. The XYL þ SC had the lowest rate of CH4 production (9%) and highest asymptotic CO2 production (81%). The findings of this study indicate that inclusion of XYL or SC additives can improve rumen fermentation and reduce greenhouse gases production. The study also established that the mixture of XYL and SC is more efficient in reducing gas and CH4 emissions for cleaner environmental production conditions in calf farming.