Opportunities Offered by Plant Bioactive Compounds to Improve Silage Quality, Animal Health and Product Quality for Sustainable Ruminant Production: A Review

Abstract

Plant bioactive compounds (PBC) are widespread in the plant kingdom, including in forage species, but their impact on silage fermentation and ruminant use of PBC-containing silage has been under-researched. The beneficial effects of PBC include plant-protein protection against excessive degradation by tannins or polyphenol oxidase leading to reduced soluble nitrogen (N) and better N use efficiency by animals, reduced emissions of pollutants such as enteric methane (CH4), improved animal health through antimicrobial, anthelmintic or antioxidant activities, and positive effects on animal product quality—especially greater increased polyunsaturated fatty acid (PUFA) content. However, there are still gaps in the research that require an interdisciplinary effort to ensure a balanced approach that co-addresses the economic, environmental and health pillars of sustainability. Here we review the potential offered by PBC to improve silage quality, nutrient use efficiency, performances and health of ruminants, and product quality. In addition, we use an example of cross-fertilization between disciplines to show that incorporating PBC-containing legume species in grass silage can provide multiple and additive effects from silage fermentation to product quality.