Comparative Physiological Assessment of Three Natural Feed Additives on In-vitro Rumen Fermentation Efficiency

This study investigated the impact of three natural feed additives: Sodium bentonite, Moringa oleifera, and red seaweed (Jania Granifera) on in vitro rumen fermentation characteristics, methane mitigation, enzyme activity, and microbial population dynamics. Rumen fluid was collected from Baladi sheep and incubated in gas-tight syringes with feed supplemented with the respective additives. After 24 hours of incubation, Key fermentation parameters were evaluated, including total gas and methane production, pH, ammonia concentration, total and individual volatile fatty acids (VFAs), extracellular cellulase activity, microbial biomass, and microbial efficiency. Quantitative PCR was employed to quantify the relative abundance of total bacteria, cellulolytic bacteria, and methanogenic archaea.The results demonstrated that red seaweed supplementation significantly reduced methane production (~34%) and the abundance of methanogenic archaea (to 0.38-fold compared to the control). However, it lowered total VFAs and cellulase activity. Moringa supplementation enhanced gas production and microbial yield, and maintained high cellulase activity and acetate production, suggesting improved microbial growth. Sodium bentonite enhanced fermentation efficiency and propionate production, exerting moderate methane suppression. Although all additives increased the relative abundance of cellulolytic bacteria, discrepancies were noted between bacterial counts and enzyme activities, suggesting potential metabolic inhibition by bioactive compounds in the additives.In conclusion, the findings support the targeted use of these natural additives to improve ruminal fermentation efficiency, modulate the ruminal microbial ecosystem, and reduce methane emissions to minimize the effects of methane on global warming.