Immunomodulation as a tool to reduce antibiotic therapy in intensive poultry production

The aim of the present review is to demonstrate the possibility of limiting antibiotic therapy in intensive poultry production through the use of various immunomodulators. In an era of increasing resistance of microorganisms to antimicrobial agents, it is particularly important to improve the efficiency of the immune system, which is indispensable for birds to survive in an environment where this system is constantly exposed to a number of stimuli that directly or indirectly affect its functioning. This is all the more important as the health of birds kept under intensive systems depends mainly on the functional status of their immune system, which determines the level of postvaccination immunity and the effectiveness of treatment. That is because its proper function is needed for the elimination of pathogenic microorganisms, stimulation of repair processes in damaged tissues and protection against reinfection. This paper focuses on the possibilities of modulating immune mechanisms and correcting the reactivity of the immunological system in poultry by using natural or synthetic immunomodulators. The results presented here suggest that methisoprinol and β-glucans are effective in modulating immune processes in turkeys and may find practical application in mass rearing of these birds: β-glucans mainly in prophylactic programmes, whereas methisoprinol both in prevention and treatment of diseases of viral etiology occurring with immunosuppression. It has also been shown that phytoncides contained in well-composed complementary feeds show immunomodulatory effects in broiler chickens and turkeys and are effective in the prevention and treatment of black head disease in turkeys. Considering the key role of the immune system in fighting pathogens, it should be concluded that synthetic and natural immunomodulators, including phytoncides used in the prevention and treatment of poultry diseases, can effectively reduce and, in some cases, replace or support antibiotic therapy.