Application of fruit and vegetable processing by‑products as ingredients in aquafeed

Aquaculture is the fastest-growing sector in the food industry. To support this growth, approximately 53 million tonnes of aquafeed are produced each year. Traditionally supported by fishmeal and fish oil, the modern aquafeed industry searches actively for novel ingredients of high nutritional value, functionality and high sustainability performance. The adoption of circular production models with the re-introduction of food processing waste in aquafeed is a valuable strategy to improve aquaculture sustainable growth. The waste generated from the fruit and vegetable processing industry (F&V by-products) arises as a source for ingredients of high nutritional and functional value. This review gathers the information available on: (i) the nutritional requirements of the most produced freshwater and marine fsh species; (ii) on the production of crops that potentially originate valuable by-products for aquafeed. The nutritional and functional value of such by-products are revised as well as the routes to process and transform these by-products into aquafeed ingredients. More than 100 peer-reviewed papers were analysed to collect information on fsh nutrition requirements, nutritional evaluation of F&V by-products, their application in aquafeed, and the processing and transformation methods allowing its use. The by-products of olive oil and wine production hold high potential to replace fsh meal and fsh oil in aquafeed. On the other hand, the extracts of seeds and peels of several fruits and vegetables can be used as a source of functional compounds to improve fsh welfare, even if they must constitute a minor component in the feed formulation. The use of F&V by-products in aquafeed requires efcient processing methods to enhance their nutritional value, eliminate antinutritional substances, ensure feed safety, and optimise resource utilisation. Emerging technologies like high-pressure homogenization (HPH) and ultrasound-assisted extraction (UAE) are efective to add value to these by-products. However, constraints related to variable composition, scalability of technologies, regulations, market acceptance, sustainability, and waste management costs still halt their full use as ingredients in aquafeed.