Protein hydrolysates derived from poultry by-products as nutraceuticals: Bioactive potential, limitations, safety considerations, and commercialization perspectives.

Over the past five decades, global agricultural production has increased substantially due to population growth, technological advancements, and farmland intensification. While this expansion has contributed to improved food security, it has also raised significant environmental concerns, driving international sustainability initiatives such as the United Nations 2030 Agenda and its 17 Sustainable Development Goals. In this context, circular economy strategies have gained attention for their potential to convert agricultural by-products into value-added resources, thereby reducing environmental burdens while creating economic opportunities. The poultry industry represents a major source of agricultural by-products, generating large quantities of feathers, blood, offal, and eggshells each year, underscoring the urgent need for sustainable utilization pathways. This review summarizes recent advances in the production of poultry by-product derived protein hydrolysates and evaluates their potential as bioactive nutraceuticals. Evidence regarding antioxidant, anti-inflammatory, and antimicrobial activities is critically examined, alongside key barriers to industrial application, including unclear mechanisms of action, batch-to-batch variability, consumer safety concerns, and regulatory constraints. Although poultry protein hydrolysates exhibit promising nutraceutical potential, further research is required to standardize production processes and address legal and safety challenges. Initial applications in animal and pet nutrition may provide practical models for safety assessment and regulatory approval, facilitating future translation into human nutrition. Interdisciplinary collaboration across food science, biotechnology, toxicology, and regulatory science will be essential to advance sustainable poultry by-product valorization.