
The use of fish protein hydrolysates aligns with global efforts to reduce waste and environmental impact in aquaculture, marking a significant step towards more sustainable food systems.
A recent study published in the Journal of the World Aquaculture Society by researchers from the University of Camerino, and Porto Conte Ricerche, Alghero, Italy, demonstrates that fish protein hydrolysates, derived from rainbow trout processing by-products, can effectively replace traditional fishmeal in feeds for gilthead sea bream juveniles without compromising growth, health, or nutritional quality.
This ingredient has the advantage of being a sustainable protein source, repurposing fish processing waste—such as heads, skin, and trimmings—into a high-value feed ingredient. Unlike plant-based alternatives, fish protein hydrolysates offer an amino acid profile that is more closely aligned with the nutritional needs of fish and is free from antinutritional factors. Additionally, the hydrolysis process ensures the high bioavailability of essential nutrients, supporting optimal growth and health in farmed species.
The study evaluated the inclusion of fish protein hydrolysates in aquafeeds over an 85-day trial, yielding significant results: juveniles fed diets enriched with this innovative ingredient achieved growth rates and feed conversion ratios (FCR) equivalent to those on fishmeal-based diets.
The body composition of the fish—including protein, lipid, and moisture levels—remained consistent across all diet groups. Furthermore, fish protein hydrolysate-enriched diets were readily consumed, confirming their palatability matches that of traditional feeds.
The adoption of this ingredient represents a practical solution to reduce dependency on wild fish stocks and mitigate waste. By incorporating by-products from rainbow trout processing into aquafeeds, the aquaculture industry moves closer to addressing environmental challenges while simultaneously enhancing the economic value of fish processing.
While the results are promising, the study noted fat accumulation in the liver across all diet groups, which researchers attributed to the inclusion of vegetable oils rather than the hydrolysates themselves. Future feed formulations may need to adjust lipid sources to minimise this issue.
Further research will also investigate the suitability of fish protein hydrolysates for larger gilthead sea bream during the on-growing phase, aiming to optimise its application throughout the farming cycle.
The use of this innovative ingredient exemplifies the shift towards a circular economy in aquaculture, where waste is transformed into valuable resources. As the industry seeks to balance productivity with sustainability, innovations like fish protein hydrolysates pave the way for eco-friendly, high-quality seafood production.