Assessing environmental sustainability of substitute feeding formulas for gilthead seabream (Sparus aurata) using Life Cycle Assessment.

The rise in fish and seafood consumption driven by aquaculture comes with its share of challenges and controversies, notably the need for expanded feed production. The use of fishmeal and fish oil to raise carnivorous fish has caused environmental problems, including ecosystem imbalance and habitat destruction, as well as ethical issues like fishing forage fish for feed instead of human consumption. Thus, the industry has been actively pursuing alternative feed ingredients to reduce reliance on fish-derived components. This progress in the aquaculture feed sector has made selecting the best feed solution complex across various fronts. This study aims to assess the environmental impacts of three feed formulations, each with different protein sources (poultry by-products, PMB, Tenebrio molitor larvae, TM, or Hermetia illucens larvae, HI), tailored for the gilthead seabream (Sparus aurata), a prized species in European aquaculture. The environmental sustainability of these alternatives was evaluated against benchmarks of fishmeal and fish oil-based feed. Employing a cradle-to-gate approach and a FU of 1 kg of product, the study utilized OpenLCA software supported by the Ecoinvent ® v3.7.1 database. The results focused on the production stages of each ingredient, including logistical and transportation aspects leading up to the final formulation. All alternatives to traditional feed demonstrated either comparable or superior environmental performance (i.e. - 66 % of PMB-f, -33 % of TM-f and - 29 % HI-f kgCO eq) with few exceptions for TM-f. This investigation highlighted how integrating innovative ingredients could positively impact the environmental footprint of aquafeed production chains. Furthermore, the main hotspots in the alternative feed formulas life cycles have been identified and viable alternatives for improvement have been proposed, such as selecting different input materials or enhancing energy efficiency. This assessment allows to guide the selection of more environmentally friendly feed formulations before their integration into aquaculture chain processes.