ISSUE FOCUS 30 FEED & ADDITIVE MAGAZINE September 2023 Stress affects the performance, health status and thus economic profitability of layers during their egg production cycle. Oxidizing agents are formed throughout the body exceeding the hen’s antioxidant capacity. Such oxidative stress leads to a suboptimal functioning of vital organs, lower egg production or -quality, as well as higher susceptibility to diseases. Therefore, productive hens are often in need of preventive tools such as highly effective bioactive antioxidants added sufficiently to their diet, for an adequate level of protection. POLYPHENOLS AS A NATURAL STRATEGY TO EFFECTIVELY CONTROL OXIDATIVE STRESS IN LAYERS Steven Beckers Global Product Manager Antioxidants Impextraco - Belgium OXIDATIVE STRESS, AN IMPORTANT METABOLIC CHALLENGE Oxidative stress is a major and still underestimated issue in animal production leading to significant performance losses. It is caused by multiple factors such as • antibiotic treatments • climatic stress, e.g. heat stress • high animal stocking densities • pathogenic pressure (low hygiene) • animal handling • feed quality and -transitioning • ventilation • induced molting Also a high metabolic activity, linked to intensive production systems, represents a key disposal factor. When too much of these stressors impact the animal, an imbalance occurs between the formation of unstable oxidants (i.e. free radicals) and the biological capacity of body cells to detoxify them. Thus, during such challenging conditions, the animal fails to produce sufficient endogenous antioxidants itself. An overload of free radicals – mainly Reactive Oxygen Species (ROS) - is generated in vivo. An important source of these unstable intermediates is the cell’s mitochondria as these are characterized by an intense oxidative metabolism (i.e. aerobic respiration), and their functioning is very sensitive to ROS-induced damage. Excess radicals attack and damage macromolecules in vital constituents of all types of body cells, such as the cell membrane (i.e. phospholipid peroxidation), mitochondria and the genetic material. Such oxidative biological injuries provoke an impaired integrity, functioning or even death of cells, resulting in inflammation which further enhances oxidative stress. Oxidative damage on a cellular level affects several tissues and eventually the whole body, i.e. systemic level. HEAT STRESS, A KEY DRIVER FOR OXIDATIVE STRESS ALSO IN LAYERS Similar to other farmed livestock species, laying hens face cellular oxidative stress during their pro-
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