Beneficial effects of plant extracts in ruminant nutrition: A review

Abstract

Use of antibiotics in animal feeds was banned hence researches on alternative natural products that can modulate ruminal fermentation have been intensified. Plant extracts are considered as natural compounds that can replace antibiotics as safe and sustainable alternatives. Extracts contain some plant secondary metabolites (PSM) that are a natural resource and are largely unexploited in ‘conventional’ animal production systems. They are considered as a source of antinutritional factors and not as a source of exploitable performance-enhancing compounds. Recent and continuing changes to legislation controlling the use of animal feed additives have stimulated interest in bioactive PSM as alternative performance enhancers. Interest is largely on their manipulative role in digestive and absorptive processes of the hindgut. The aim of the present review is to discuss the use of plants and their extracts to manipulate the rumen microbial ecosystem to improve the efficiency of rumen metabolism. The bioavailability of PSM and their actions on peripheral metabolism will be considered with a view to improve animal performance. In order to fully exploit their bioactive properties for the benefit of animal performance, modes of action need to be understood.