The growing demand for sustainable aquaculture calls for innovative feed solutions that reduce reliance on conventional ingredients such as fishmeal and soybean meal, which compete with human food production. Circular economy principles promote the use of agricultural by- products as alternative feed ingredients, minimizing resource competition and waste.
In central Italy, small-scale trout (Salmo trutta fario and Oncorhynchus mykiss) farms have faced economic challenges due to regulatory restrictions on restocking non-native species and the economic impact of the 2016 earthquake in the Marche region. Many farms are struggling to remain operational, pushing the need for cost-effective and sustainable practices.
As part of the Horizon 2020-PRIMA AgrI-fiSh project (2022-2025), this study tested novel aquaculture feeds replacing up to 70% of conventional feed components with agricultural by- products. The experimental trials were conducted in a trout farm in Visso (Italy), testing two experimental diets (A and B) derived from legume and cereal processing waste and grape by- products, known for their antioxidant and fatty acid content.
Brown trout (n=900) were reared in nine tanks (three per diet) under controlled conditions. Growth performance and condition factor (K) were evaluated using one-way ANOVA and post-hoc Tukey’s test (p<0.05). While all groups showed increased total length, final body weight was lower in experimental diets compared to control.
Further studies on rainbow trout, as well as ongoing trials in Spain on seabass and in Algeria on tilapia, aim to refine these formulations and improve productivity, fostering a more sustainable and resilient aquaculture sector.