Resumen:
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.
Descripción:
Worldwide, agricultural farming systems, such as livestock
production, face the increasing challenge of maintaining future
global demand for meat and dairy products because of an expected
increase in population (Wiedemann et al., 2017). The Food and
Agriculture Organization (FAO, 2006) expects that an increase in
purchasing power for food from animal sources raises the yearly
demand to 465 and 1.043 million t for meat and milk products.
Besides, the FAO estimates the growth of global population to reach
9.6 billion by the y 2050 (FAO, 2016), with a doubled purchasing
power for meat and dairy products. To meet this rise in demand,
agricultural systems need to devise a means to adapt to the probability
of dangerous climate change and become more resilient,
productive and sustainable (FAO, 2016)