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Upcycled Animal Protein Hydrolysates for Gilthead Seabream: Impact on Growth Performance, Nutrient Utilisation,
A Alves-de-Oliveira1,2, M Monteiro1,2, T Sá1
1CIIMAR/CIMAR LA, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Av. General Norton de Matos S/ N, Matosinhos 4450-208, Portugal, up.pt.
Aquaculture Nutrition
|July 19, 2026
Summary
Novel protein hydrolysates from insect, fish, and swine by-products can replace high-quality fish protein hydrolysates in gilthead seabream diets. These alternative protein hydrolysates support circular aquafeed formulations without compromising growth or feed efficiency.
Area of Science:
- Aquaculture and Animal Nutrition
- Sustainable Feed Development
- Circular Economy in Agri-food Systems
Background:
- Increasing demand for sustainable aquafeed ingredients drives interest in protein hydrolysates (PHs) from processed animal proteins (PAPs).
- PHs offer a method to upcycle protein-rich waste streams into valuable aquafeed components.
- Local circular feed systems are crucial for reducing reliance on traditional feed sources.
Purpose of the Study:
- To evaluate novel PHs from insect meal, fish by-products, and swine by-products as replacements for a commercial fish PH (CPSP90).
- To assess the impact of these alternative PHs on gilthead seabream (Sparus aurata) growth, nutrient digestibility, and intestinal health.
- To determine the potential of these PHs in supporting circular aquafeed formulations.
Main Methods:
- Gilthead seabream juveniles were fed diets containing 3% of alternative PHs (insect, fish, swine) or a control diet with CPSP90 for 88 days.
- Voluntary feed intake (VFI), final body weight (FBW), and feed conversion ratio (FCR) were measured.
- Nutrient digestibility and anterior intestine histomorphology were analyzed. Gene expression analysis was performed on fish fed the SWINE and INSECT diets.
Main Results:
- All experimental diets were well accepted, with similar VFI, FBW, FCR, and intestinal histomorphology across treatments.
- Fish fed the SWINE diet showed altered muscle gene expression related to myogenic differentiation, but no growth improvement.
- Fish fed the INSECT diet exhibited reduced lipid losses and potential metabolic adjustments, while the FISH diet group showed performance comparable to the control.
Conclusions:
- Alternative protein hydrolysates from insect, fish, and swine by-products demonstrate potential as replacements for high-quality fish PHs in gilthead seabream diets.
- These novel PHs can contribute to circular aquafeed strategies while maintaining fish growth and feed efficiency.
- Further research into specific PH sources and their metabolic effects can optimize their use in sustainable aquaculture.
