The nutritional quality of feed affects farmed salmon health and welfare significantly. Shifts from fish-based to plant-based feeds have welfare implications that require careful management.
Nutritional welfare in farmed salmon is a consequence of tension between sustainability goals and species-appropriate feeding. Atlantic salmon evolved as marine predators requiring omega-3 fatty acids, high-quality protein, and specific micronutrients from fish and crustacean prey. Substituting plant proteins reduces production costs but creates welfare challenges: soy-based feeds cause intestinal inflammation that impairs nutrient absorption and immune function. Vitamin and mineral deficiencies from inappropriate feeds cause skeletal deformities and metabolic disease. Algal oil — providing marine omega-3 directly from the algae that fish accumulate it from — represents a nutritionally appropriate and sustainable alternative to fish oil. Feed formulation is a welfare issue as much as a sustainability one, and both dimensions must be addressed in responsible aquaculture.