L22 Natural antioxidants and stresses in poultry production: from vitamins to vitagenes Peter F. Surai 1-5* , Vladimir I. Fisinin 5-6 1 Trakia University, Stara Zagora, Bulgaria; 2 Szent Istvan University, Godollo, Hungary; 3 Sumy National Agrarian University, Sumy, Ukraine; 4 Odessa National Academy of Food Technologies, Ukraine; 5 Russian Academy of Science, Moscow, Russia; 6 All Russian Institute of Poultry Husbandry, Sergiev Posad, Russia. *Corresponding author: psurai@feedfood.co.uk Keywords: antioxidants, poultry, stress, vitagenes Summary Commercial poultry production is associated with various stresses leading to decrease of productive and reproductive performance of growing chickens, parent birds as well as commercial layers. In gener- al, there are four major types of stress in poultry industry: technological, environmental, nutritional and internal stresses. Growing body of evidence indicates that most of stresses in poultry production at the cellular level are associated with oxidative stress due to excess of free radical production or inadequate antioxidant protection. Therefore, dietary antioxidants are considered to be the main protective means to deal with various stresses in poultry production. Indeed, the development of the effective antioxidant so- lutions to decrease negative consequences of commercially- relevant stresses is an important task for poultry scientists. One of such approaches is based on possibilities of modulation of vitagenes, a family of genes responsible for animal/poultry adaptation to stress. The new concept of fighting stresses is based on an idea that supplying birds with various antioxidants via the drinking water could help them to effectively deal with stress conditions. In fact, it was proven that inclusion of vitagene-regulating com- pounds (carnitine, betaine, vitamin E, etc.) in water, as well as some minerals, vitamins, electrolytes and organic acids could be effective in fighting various stresses. Stresses in poultry production Commercial poultry production is associated with various stresses leading to decrease of productive and reproductive performance of growing chickens, parent birds as well as commercial layers. In gener- al, there are four major types of stress in poultry industry: technological, environmental, nutritional and internal stresses (Surai and Fisinin, 2016a; 2016b; Table 1).In fact, a list of commercially-relevant stress- es in poultry production could be quite long, but the main point is the most of the stresses suppress repro- ductive performance of parent birds including reduced fertility and hatchability. Furthermore, stresses are associated with impaired feed conversion, reduced average daily weight gain, immunosuppression and increased mortality in growing birds. Growing body of evidence indicates that most of stresses in poultry production at the cellular level are associated with oxidative stress due to excess of free radical production or inadequate antioxidant protection (Surai, 2002; 2006; Surai and Fisinin, 2016a; 2016b). According to the recent literature review, heat and diet are among main means causing oxidative stress in domestic birds that may lead to biological damage, serious health disorders, lower growth rates, and, hence, economic losses (Estevez, 2015). Therefore, dietary antioxidants are considered to be the main protective means to deal with various stresses in poultry production (Surai, 2002; 2006) Antioxidant systems of the body During evolution, living organisms have developed specific antioxidant protective mechanisms to deal with ROS and RNS (Surai, 2002). Therefore it is only the presence of natural antioxidants in living organisms which enable them to survive in an oxygen-rich environment. The general term antioxidant systems  describes these mechanisms, which are diverse and responsible for the protection of cells from the actions of free radicals. These systems include: Natural fat-soluble antioxidants (vitamins A, E, carot- 116