Antimicrobial properties

The antimicrobial mechanism of aromatic plant essential oils mainly involves alteration of fatty acid outer membrane, damage to cytoplasmic membrane, depletion of proton motive force, metabolites and ion leakage. The antimicrobial effect of compounds such as carvacrol, thymol, eugenol and cinnamaldehyde in plant essential oils is significant, and a variety of compounds in essential oils often have synergistic effects, which can efficiently inhibit the growth of harmful microorganisms in the rumen and intestine of animals, reduce methane emissions from ruminants, contribute to the improvement of animal performance, and the accumulation of active ingredients in metabolic tissues can inhibit the growth of spoilage or pathogenic bacteria . In addition, feeds are prone to mold in storage, and animals feeding on moldy feeds can lead to chronic poisoning. Plant essential oils can inhibit the growth of mold and slow down the growth of mold, thus ensuring the quality of feeds.

Anti-oxidation

Phenolic compounds in essential oils can act as reactive oxygen scavengers to reduce damage to proteins, DNA and cell membrane lipids; they can affect the activity of antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, etc., which have the function of inhibiting or delaying lipid oxidation in animals to improve the quality of meat and, to a certain extent, the flavor of meat. The antioxidant compounds in essential oils may also enter the circulatory system and be retained in tissues such as muscle, thus ensuring longer shelf life of fats, meat and eggs. The antioxidant properties of plant essential oils may also influence the properties of the feed itself, for example by protecting it from oxidation-induced spoilage and thus extending its storage time.

Anti-viral

Eucalyptus essential oil, garlic essential oil and peppermint essential oil can be used directly to prevent or treat viral diseases in poultry and livestock, and have a preventive effect on epidemics such as avian influenza, swine fever and rinderpest.

Immunomodulation

The chemical components of essential oils such as carvacrol, thymol and cinnamaldehyde can stimulate the animal organism to produce high levels of antibodies, while increasing the number of lymphocytes and promoting a variety of immunomodulatory effects to maintain the animal organism at a healthy level.

Flavor Regulation

Most plant essential oils are beneficial to the flavor and palatability of feeds. By stimulating the secretion of digestive enzymes, increasing gastric and intestinal motility, enhancing animal appetite and promoting digestion and absorption, and increasing animal growth rate and feed conversion, plant essential oils regulate animal nutritional metabolism and improve their performance.

Due to these functions, aromatic plants are considered to be one of the most promising categories of environmentally friendly feed additives, especially those with outstanding antibacterial and antioxidant functions, such as oregano, thyme and rosemary. Aromatic plant essential oils have a broad prospect in the field of animal production. In order to promote the utilization of plant essential oils in animal production, the active ingredients, pharmacological mechanisms of action, toxicity and clinical effects of essential oils should be fully researched, while new plant species with high active ingredients should be screened and suitable areas should be selected for large-scale planting to meet the development needs of the vigorously growing livestock industry.

The Institute of Botany, Chinese Academy of Sciences has selected and bred new varieties of oregano with high essential oil content and high carvacrol content for the development of natural plant feed additives targeting the reduction of antibiotic use.