The growing demand for healthy seafood has made aquaculture one of the fastest-growing food production sectors in the world.
In addition to creating new jobs, this branch of agriculture ensures a steady supply of fish, which is increasingly sought after on the market, while at the same time it has great potential to reduce pressure on wild fish populations, increase food security, and stimulate the development of sustainable technologies and innovations that contribute to marine conservation and the growth of the blue economy.
One of the biggest challenges in fish farming is reducing dependence on fishmeal and fish oil, the key ingredients of fish feed that are largely obtained from already depleted stocks of small pelagic fish. This is why the EU, through the Circular Economy Action Plan, promotes the development and use of sustainable alternatives, such as proteins from insects and poultry by-products, in order to reduce pressure on the sea and increase supply security.
In line with these recommendations for sustainable aquaculture growth, Croatian scientists from the Institute of Oceanography and Fisheries and the Croatian Veterinary Institute, in collaboration with Italian colleagues from the University of Udine and domestic fish-farming companies, carried out the largest trial to date in the Adriatic. On a commercial scale, they tested new fish feed formulas that significantly reduce the share of marine ingredients, replacing them with sustainable land-based sources. The results of the research were published in the respected international journal Future Foods.
“Through preliminary laboratory research we identified two formulas that proved most effective for the farming of gilthead sea bream and European sea bass. These feeds are based on a high proportion of proteins from the poultry industry and insect meal, specifically black soldier fly, while part of the lipids come from plant-based sources,” said Dr. Tanja Šegvić Bubić, senior scientist at the Aquaculture Laboratory of the Institute in Split.
However, to verify the sustainability of such formulas, it was necessary to test them in commercial sea cages, where fish growth and quality are strongly influenced by factors such as water temperature, stocking density, and everyday farming practices.
“During the research, we compared the new formulas with the standard feed used on farms, conducting trials at fish farms in the central and northern Adriatic. Our goal was to determine whether our mixtures could deliver equal or better results under real farming conditions, as had previously been shown in laboratory trials,” added Dr. Šegvić Bubić.
To obtain precise data, the team monitored growth, fillet yield, and nutritional composition of the fish (basic chemical composition, mineral profile, and fatty acids), applying methods in line with relevant ISO standards.
The results are remarkable and could represent a breakthrough for the future of fish farming. It was shown that fish fed the new formulas grew just as well as on standard feed, and in the case of sea bream, the results were even better – higher final body weight, higher specific growth rate, lower feed conversion ratio, and greater fillet yield, along with higher values of polyunsaturated fatty acids such as omega-3.
For sea bass, growth was similar to that on standard feed, but fillet yield was higher, while the profile of saturated and unsaturated fatty acids in both species remained within recommended values for human nutrition.
“It is a special feeling, after so many years of work, to see such good results. We have shown that land-based protein sources can be successfully used to maintain or even improve farming performance and fish quality, while at the same time aligning with environmental sustainability goals and preserving key nutrients important for human health,” concluded Dr. Šegvić Bubić.
The research was funded by the Interreg project AdriAquaNet (Project ID 10045161), with additional support from the SustainAqua project, financed through the Next Generation EU – National Recovery and Resilience Plan 2021–2026.
