Mechanisms of Moringa oleifera Leaf Extract Influences Productive Performance, Immunity, Milk Composition, and Rumen Microbiota in Ruminants: A Review

Moringa oleifera leaf extract (MOLE), including polysaccharides, polyphenols, amino acids and other extracts, are increasingly being used as feed additives in ruminant nutrition due to their high profiles of bioactive compounds. This comprehensive narrative review aims to review current research on their use in ruminant production regarding their productive performance, immune status, rumen microbiota and fermentation. Dietary supplementation with MOLE enhances growth rates and feed conversion efficiency, as well as immune status, milk yield and rumen microbiology, in ruminants by improving nutrient digestibility and metabolic efficiency. Additionally, MOLE exerts significant immunomodulatory effects, and studies indicate that immunoglobulins, antioxidants, cytokines, and enzymes reduce oxidative stress markers and incidence of subclinical diseases in dairy animals. Furthermore, supplementation with MOLE often increases milk fat and protein content while reducing somatic cell counts (SCCs) in milk. MOLE enhance the function of the rumen fermentation profile by increasing volatile fatty acid (VFA) production, especially propionate, and also regulating the stability of rumen pH. Additionally, it also selectively promotes microbial community diversity, enhances the population of cellulolytic bacteria and has a suppression function in protozoa and methanogens. Moreover, MOLE also contributes to improving fiber degradation and reducing the emissions of methane. In conclusion, MOLE is considered as a viable natural strategy to promote productivity, immune function, health, and environmental sustainability while decreasing methane production in ruminant production.