# Application of Natural Antioxidants from Fruits Waste for Improving Egg Quality Characteristics
## 2 Methodology of Selecting Relevant Articles  
The search conducted was limited to research articles having the full text available in the English language. The main databases used were Web of Science, PubMed, Google Scholar, and Scopus. Primary search keywords used were fruits' waste, fruits' pomace, antioxidant compounds, laying hens, performances, egg quality, shelf life, and bioactive compounds. Searches were also performed using the taxonomic names of the plants. The search covered the literature published from the most recent years and published in peer-reviewed journals. Book chapters, if available online, were also incorporated. The selection process was refined through criteria designed to identify studies directly related to the application of fruit waste in poultry feed formulations, specifically aimed at evaluatingtheir effects on production performances, health status, and egg quality. Studies were considered if they evaluated the chemical and functional aspects of natural antioxidants from fruit waste (peels, seeds, pulp, or pomace) and their effects on various egg quality characteristics and nutritional value, assessing outcomes in egg production or quality as well as their implications on animals' health. Studies with insufficient experimental rigor, an undeclared sample size, or those without the potential for applications in real-world experimental trials were not considered. We focused on studies that used fruit waste with higher availability after fruit processing, in a sustainable manner. After the literature survey, we found over 150 papers that described the chemical composition of the fruit waste, the effects on laying hens' diets, or both. These synthesized results aim to highlight potential mechanisms through which fruit-derived antioxidants contribute to egg quality improvements and the potential trends for future research. The Role of Natural Antioxidants on Laying Hens' Performances, Egg Quality Characteristics, and Shelf Life  
Natural antioxidants, particularly those derived from plant-based sources, have been proposed as safer alternatives to synthetic ones and offer additional health advantages including reduced inflammation as well as enhanced protection against diseases [21]. Among multiple plant materials used in antioxidant activity support, fruit waste stands out as a sustainable and abundant reservoir of bioactive compounds. Some fruit waste contains significant amounts of polyphenols, flavonoids, carotenoids, and vitamins [22; 23]. Through repurposing and reusing these off-cuts from fruits, the poultry sector would be able to address both consumers' requests for natural additives in animal origin products and the necessity for greater sustainability measures in feed and food production methods. In laying hens' nutrition, antioxidants are essential because they protect the cells and tissues from oxidative damage, which, over time, degrades the quality of the eggs. A recent study by [PERSON] et al. [24] found that oxidative stress in laying hens can be caused by several issues, such as illness, environmental stressors, and the metabolic demands of egg production. Oxidative stress in birds can have a detrimental effect on the health status and quality of the eggs they lay, leading to lower productivity and a lower quality of the final products [25; 26]. Other recent studies reported that bioactive compounds from several types fruit waste demonstrated great promise in this area. For example, rosehip meal at 3% improved egg yolk lipids and albumen protein quality, health indices, and the shelf life of stored eggs due to rosehip's high vitamin C, polyphenols, and antioxidant capacity content [20]. Pomegranate peel waste at 2.5% and 5% inclusion levels increased yolk coloration and reduced yolk MDA content while improving lipids' content, as shown by [PERSON] et al. [27], which might be caused by anthocyanin's presence.