Solid-state fermentation of fruit and vegetable discards: production of nutritionally enriched ingredients and potential bioactive extracts for aquaculture sector

Abstract

A significant amount of fruits and vegetables are wasted each year, causing negative impacts on both the economy and the environment. Repurposing these surplus fruits and vegetables as animal feed could reduce feeding costs while aligning with efforts to prevent resource wastage and enhance processing plant efficiency. The present research aimed to optimize a solid-state fermentation (SSF) process to produce nutritionally and functionally enriched aquaculture feed ingredients. SSF led to increased protein and fat content, thereby improving the essential amino acid profile and fatty acid concentration in the fermented ingredients. Additionally, an extraction process led to a bioactive extract with in vitro antioxidant and antimicrobial properties, effective against bacteria from Vibrio, Tenacibaculum, Bacillus, and Staphylococcus genera. In vivo trials including 5\% of fermented ingredients showed no differences in productivity parameters compared to a control diet in sea bass. However, including 0.5\% of the fermented extract in the diets reduced mortality when sea bass was exposed to the pathogen Tenacibaculum maritimum.