Deciphering the role of Moringa oleifera seeds and probiotic bacteria on mitigation of biogas production from ruminants.

Maintaining cleaner and more sustainable ecosystems by mitigating greenhouse gas (GHG) emissions from livestock through dietary manipulation is in demand. This study was aimed to assess the effect of Moringa oleifera seeds and probiotics (Pediococcus acidilactici BX-B122 and Bacillus coagulans BX-B118) as feed supplements on GHG production and fermentation profile from steers and sheep. The treatments included diets containing 0, 6, 12, and 18% of M. oleifera seeds meal and a mixture of probiotic bacteria (0.2 ml/g of diet). Total biogas production, CH₄, CO, and H₂S emission from animals (up to 48 h), rumen fermentation profile, and CH₄ conversion efficiency were recorded using standard protocols. Results showed interaction among M. oleifera seeds and probiotics on asymptotic biogas production and total biogas production up to 48 h (P < 0.05). The rate of CH₄ emission in steers was reduced from 0.1694 to 0.0447 ml/h using 6 and 18% of M. oleifera seeds (P < 0.05). Asymptotic CO and the rate of CO production were increased (P < 0.05) by supplementing different doses of M. oleifera seeds and probiotics. Adding 12% of M. oleifera seeds and probiotics reduced H₂S production from 0.0675 to 0.0112 ml H₂S/g DM (at 48 h of fermentation) in steers. In sheep, the additives mitigated H₂S production from 0.0364 to 0.0029 ml H₂S/g DM (at 48 h of fermentation), however there were not interaction (P = 0.7744). In addition, M. oleifera seeds and probiotics reduced the pH level and dry matter degradability (DMD) in steers and sheep (P < 0.0001) showing a positive impact on CH₄:ME and CH₄:OM (in steers) and CH₄:SCFA (in sheep), while the interaction was not significant (P > 0.05) for CH₄:SCFA (in steers) and CH₄:ME and CH₄:OM (in sheep). In conclusion, the interaction of M. oleifera seeds and probiotics in the feeding diet reduced GHG emissions and affected the fermentation profile of steers and sheep.