Dietary trace mineral (Cu, Fe, Mn, Zn, and Se) source and levels on production parameters, fillet quality, mineralization, and skin morphology of 1+ and 0+ Atlantic salmon across regions in Norway

Summary

The shift from marine-based to plant-based ingredients in Atlantic salmon feeds presents a complex challenge due to varying nutrient levels and combinations, including mineral levels. Studying the effects of new feeds in large, slaughter-ready fish poses logistical and financial challenges. Unlike most mineral nutrition research studies, typically conducted under controlled conditions, the current study utilizes large-scale research license experiments, providing a vast amount of systematically gathered information. This approach allows for a more conclusive overview of how mineral supplementation affects salmon production in a commercial setup. This study aimed to explore the practical implications of using different dietary levels of essential trace minerals (Cu, Fe, Mn, Zn, and Se) in either organic or inorganic forms in salmon feeds. A total of 12 full-scale feeding trials were conducted across three locations representative of Norwegian salmon production: Northern, Mid, and Western Norway. Each location included four trials with nutritional interventions replicated for 1+ and 0+ smolt. Results indicated that quality parameters, slaughter yield, and welfare indicators were significantly influenced by smolt age, location, and mineral level. Specifically, reduced Fe levels mitigated prooxidative effects and increased the availability of essential trace minerals, while increased Zn supplementation improved skin welfare. The use of organic minerals resulted in reduced gaping, elevated mineral levels in key tissues, and enhanced production performance. This article highlights the complex interplay between dietary mineral supplementation and fish performance, quality, welfare indicators, and tissue mineralization in commercially produced Atlantic salmon. The findings from this study demonstrate the critical role of trace minerals in improving mineral availability and overall fish welfare, underscoring the importance of considering multiple factors in formulating optimal feed compositions for enhancing fish health, performance, and welfare in aquaculture practices. These insights offer significant advancements over previous studies by providing practical solutions to the challenges of modern feed formulations and their impacts on Atlantic salmon production.