The impact of phytogenic feed additives on ruminant production: A review

Ruminant livestock, a vital source of high-value proteins such as red meat and milk, requires efficient and sustainable farming practices. To enhance production and quality, researchers have turned to various feed additives, with phytogenic feed additives (PFA) gaining significant attention following the European Union's ban on antibiotics in 2006. PFA, which are plant- derived products, are also often referred to as phytonutrients, phytochemical, plant natural compounds, plant bioactive compounds, or herbal feed additives, and are natural and safe alternatives to synthetic antibiotics. The review highlights the diverse benefits of PFA in ruminant livestock production. These compounds can improve ruminant performance, rumen fermentation, milk production, reproductive health, blood profiles, antioxidant and antimicrobials properties, immunity and meat quality. Specific bioactive compounds in PFA, such as essential oils, polyphenols and flavonoids, exhibit significant antimicrobial, antifungal, antioxidant and antiparasitic properties. They also modulate ruminal fermentation, reduce methane emission, and enhance feed intake and palatability. The mechanisms through which PFA function include improving feed utilisation and growth performance, as well as mitigating oxidative stress and inflammation. The mechanism behind this effect is based on donating hydrogen atoms, activating detoxifying enzymes and quenching reactive oxygen species. The review underscores the need for further research to fully understand these processes. Considering the rising global demand for meat and dairy products, PFA present a viable solution for sustainable livestock farming. They offer a natural effective and safe alternative to antibiotics, promising improved productivity, animal health, and food quality. This review aims to provide a comprehensive characterization of PFA and their potential in ruminant nutrition and production.