Recent Advances in Plants Secondary Metabolites and Their Application as Rumen Fermentation Manipulating Agents in Ruminants
Nutrition of ruminants is dominated by manipulation of the microbial fermentation that occurs in the rumen. Feed additives of natural origin were the potential of plant extracts as beneficial manipulators of ruminal fermentation. In recent years, many researches confirm that plants produce secondary metabolites, such as alkaloids, saponins, tannins, terpenoid, essential oil and other compositions, which have antimicrobial, growth-promoting, antioxidation, and immunological enhancing properties, making them to be potential alternatives to antibiotics to manipulate microbial activities in the rumen. Thus, research and applications of plant secondary metabolites as ruminant feed additives will become a focus. The objectives of this paper are to review the most important findings on effects of the plant extracts in the rumen, to describe their identified origins, categories, effective components and modes of action, and to provide some ideas for further investigation and applications of plant extracts in ruminant nutrition.