Potential of phytobiotics in poultry nutrition

Prof. Dr. Michael Grashorn,WG Poultry Science, Dept. of Livestock Population Genomics (470c),University of Hohenheim, Germany

Keywords:Broiler, laying hen, nutrition, feed additives, phytobiotics, anti-bacterial, anti-oxidant, immunity

Abstract
Antibiotics have been used in animal feeds for a long time as growth promoters. They helped to overcoming unfavorable environmental conditions, high infection pressures and stress situations. Due to increasing resistances of microorganisms against antibiotics in humans the European Union banned the use of antibiotics as growth promoters in animal feed in 2006. Meanwhile, more countries have introduced or are considering to introducing a ban on the use of antibiotics in animal nutrition. To overcoming critical situations in poultry production alternative feed additives are needed. Besides prebiotics, probiotics and organic acids, phytobiotics seem to be the most promising group. Phytobiotics are plant derived feed additives, including essential oils, which contain a broad number of pharmacologically active compounds with proven impact on wellbeing and health of the animals. Antioxidant, antifungal, antibacterial, antiviral, sedative and antidepressant activities of phytobiotics are described for poultry in literature. Although, the mode of action is not clear for all active compounds, it is acknowledged that there is a stimulation of the secretion of digestive enzymes (resulting in better performance), a direct inhibition of the growth of bacteria, viruses and fungi (reducing the risk of infectious diseases), and a stimulation of the immune system (better health). A broad variety of plant derived feed additives exists, which vary distinctly in their composition and thus in their action. In the beginning of the research on phytobiotics mainly dried herbs and spices have been used, as e.g. fennel, oregano, thyme, sage, garlic. But, soon it was clear that extracts, especially of essential oils, are more promising. Major essential oil components are carvacrol, thymol, γ-terpine and p-cymene. Mostly, phytobiotics improve growth, egg production and feed conversion, whereas, effects on product quality are less clear, besides a better oxidative stability of the meat. In conclusion, phytobiotics are a well suited alternative to antibiotic growth promoters in laying hen and broiler feeding. Although, the knowledge on the action of phytobiotics is continuously increasing there is still a need for further research. The review will try to give an actual overview on the state of the art of using phytobiotics in laying hen and broiler feeding.