Poultry by-product meal in diets for farmed Atlantic salmon supports high growth performance, fish welfare and fillet quality under commercial-like field conditions

Continuous growth in Atlantic salmon aquaculture and increased feed-food competition are driving us to implement increased circularity in our food systems. Poultry by-product meal is an underutilized, high-quality protein source, with great potential in diets for farmed Atlantic salmon in Europe. A commercial-like field experiment was conducted with 435,000 Atlantic salmon fed one of three diets: A commercial-like control diet based on conventional protein sources, and two test diets where poultry by-product meal replaced 5 % and 10 % of the crude protein content, respectively. The objectives of this study were to evaluate the effect of poultry by-product meal on growth performance, fish welfare and fillet quality. After 11 months of feeding to triplicate sea cages, the mean weight of the fish increased from 482 g to 5.9 kg. No differences were found between the dietary groups for growth performance, mortality, feed conversion ratio, gut histology or fillet quality parameters such as gaping, firmness, colour or fatty acid composition. We conclude that poultry by-product meal can be used in diets for Atlantic salmon in inclusions up to 10 % without compromising growth performance, fish health and welfare or product quality. • Dietary poultry by-product meal inclusion did not compromise fillet quality. • Gut histology showed no adverse effects from poultry by-product meal inclusion. • Poultry by-product meal can replace 10 % of conventional protein sources. • Fish welfare was not compromised by poultry by-product meal inclusion.