# Antioxidant and Antimicrobial Properties of Selected Phytogenics for Sustainable Poultry Production
## 2 Antioxidant Properties of Phytogenic Products Used in Poultry Production  
Phytogenics are very rich in bioactive compounds with potent antioxidant properties that can modulate the immune system, reduce oxidative stress, and thus improve growth performance and meat quality [11]. Due to their ability to shield lipids and proteins, antioxidants are frequently and effectively used as natural additives in poultry feed. They are increasingly becoming popular as alternatives to synthetic antioxidant additives, such as butylated hydroxytoluene and tocopheryl acetate. Their beneficial effects are mediated through the improvement of the antioxidant status of poultry [12; 13], including increasing the activities and gene expression of antioxidant enzymes [3] whilst decreasing lipid peroxidation [14]. In addition, the phytochemicals can modulate the antioxidant status of poultry through their alteration of meat fatty acid composition from the saturated (lauric, myristic, palmitic, and stearic acids) to the monounsaturated (e.g., oleic acid) and polyunsaturated (PUFA) (long-chain) fatty acid lineages [4; 7]. Saturated fatty acids are undesirable in meat due to their association with hypercholesterolemia and other chronic metabolic diseases in humans [4; 7] whilst PUFAs, particularly omega-3 fatty acids, are associated with good health [15]. Furthermore, some of the antioxidant bioactive compounds in phytogenics, such as anthocyanins, polyphenols, retinol, and tocopheryl, have good pigmentation-imparting effects [16; 17], with the potential to enhance meat color. These compounds also have the potential to enhance meat stability by delaying the oxidation of stored meat. According to [PERSON] et al. [18], the antioxidant defense and immunity-boosting qualities of dietary plant polyphenolics help maintain a balance between the generation of free radicals and their neutralization by supporting the antioxidant system along the gut lining. The significant antioxidant activity of polyphenolics is attributed to the presence of hydroxyl groups, which function as hydrogen donors to surrogate radicals created during the initial stage of lipid oxidation, thus delaying the generation of hydroxyl peroxide. Indeed, the intake of phytogenic products in poultry results in an increase in serum antioxidant enzyme activities and a decrease in the malondialdehydeehyde level [15; 16; 17; 18]. The antioxidant propertiesof phytogenic compounds, such as \(\alpha\)-tocopherol acetate or butylated hydroxytoluene, are useful in the protection of dietary lipids from oxidative damages [19]. Plant oils containing natural antioxidants contribute to the improved oxidative stability of meat and meat products containing higher levels of polyunsaturated fatty acid. Accordingly, antioxidants in phytogenic products have the potential to improve meat quality [16]. This is achieved when plant-derived antioxidants scavenge excess oxygen free radicals and chelating metals [20] or by increasing the activity of antioxidant enzymes, thereby reducing oxidative damage [21] in meat products. Furthermore, the protective effects of most dietary phytochemicals are a result of multiple distinct mechanisms [22], and hence, meat quality is affected by protecting muscle function in a live animal body. In addition, phytochemicals have been shown to benefit animals in terms of improved performance, meat quality [23], and an enhanced endogenous antioxidant system. This is possibly done by directly affecting specific molecular targets or indirectly as stabilized conjugates affecting metabolic pathways [24]. As a result, both external and endogenous stimuli activate and deactivate critical events in intracellular relays, allowing proper signaling to diverse downstream target molecules in a highly sophisticated manner to fine-tune cellular homeostasis [25].