Resumen:
In livestock production, ruminal fermentation leads to significant loss of digestible feed energy and increase
methane (CH4) and carbon dioxide (CO2) productions. These gases are the major sources of
greenhouse gases that cause environmental degradation and climate change. The present study aimed at
investigating the sustainable control of CH4 and CO2 production from ruminal fermentation by evaluating
ruminal inclusion of Escherichia coli (E. coli) on diets containing different levels of soybean hulls (SH)
replacing corn grains (CG). Three different levels of mixed ration were prepared; CG was replaced with
SH at three different levels (per kg dry matter (DM)): 0 g (control), 75 g (SH 75), and 150 g (SH 150). The
E. coli was used at four doses: 0, 10, 20 and 40 mL/g DM of substrate. The SH rations had decreased linear
and quadratic (P < 0.05) effects on asymptotic gas production (GP). Interactions occurred between SH
ration and E. coli doses (P < 0.05) on the fractional rate of GP. E. coli at all doses did not produce any effect
on the CH4 production parameters. However, the control had the highest CH4 production at 40 mL/g DM
E. coli addition compared to other SH rations and their respective E. coli doses. SH ration linearly
(P ¼ 0.006) decreased asymptotic CO2 production. The study established that SH ration and E. coli doses
had no effect on the CH4 production; however, they had a decreased effect on asymptotic GP. This study
demonstrated that inclusion of SH 150 ration at different E. coli doses reduced asymptotic CO2 production
without effect on CH4 production and this may be useful for the sustainable mitigation of CO2 production
from livestock production.