Aromatic essential oils in feed substitution and animal production

Aromatic plant essential oils are a mixture of volatile compounds extracted from the tissues and organs of plants (flowers, leaves, stems, seeds, fruits, roots or bark) and are secondary metabolites of plants. It protects plants against fungal, bacterial and viral invasion, defends them against insect and herbivore feeding, and also attracts pollinators by scent to facilitate the spread of pollen and seeds. The diversity of plant essential oil compounds determines the diversity of their biological activities, such as antibacterial, antioxidant, anti-inflammatory, antiviral and anti-immune stimulation. The use of aromatic plants in China has a long history, as early as more than 5,000 years ago in the time of Yandi Shennong, aromatic plants were used by people to get rid of plague and drive away epidemics and purify the body and mind. With the development of the times, aromatic plants are increasingly used in food, daily chemical and pharmaceutical industries.

In the livestock production system, the uncontrolled use of antibiotics may not only lead to the production of "super bacteria", but also cause unsafe livestock products and environmental pollution. In response to the current problem of antibiotic abuse, people are actively looking for new antibiotic alternatives, and aromatic plant essential oils contain natural bioactive compounds, and less toxic, less residual, less likely to develop resistance, as an alternative to antibiotics gradually began to play its own advantages.

Feed additives are compounds added to animal feeds to improve their health and growth and production performance. These compounds have functions such as enhancing digestibility, maintaining and enhancing the distribution of beneficial flora in the intestinal tract, and improving the quality of products of animal origin.

Since the 1990s, it has become clear that the use of antibiotic-based additives in animal feeds can lead to the development of bacterial resistance. Drug resistance can be transmitted through the food chain and has a significant impact on food safety as well as human health. As a result, several countries have enacted a series of policies and regulations to restrict the use of antibiotics in feed. The Ministry of Agriculture and Rural Affairs Notice No. 194 stipulates that from July 1, 2020, feed manufacturers will stop producing commercial feed containing growth-promoting drug feed additives (except traditional Chinese medicine). These policies have given a strong impetus to the development and utilization of plant-derived feed additives, and the use of aromatic plants as an alternative to antibiotics and other synthetic substances is one of the eco-friendly strategies to solve the dilemma of the livestock feed industry. The use of plant essential oils as feed additives in animal production has grown significantly over the past few decades.

Aromatic plant essential oils have multiple functions as feed additives, based on the following aspects.