Seasonal effect on the biochemical composition of Atlantic seaweeds cultivated in integrated multitrophic aquaculture

Seaweeds are recognized as sustainable food sources rich in nutrients and bioactive compounds, but their composition is highly influenced by seasonality. This study evaluated the biochemical profiles of Ulva sp., Fucus vesiculosus, Porphyra dioica, and Palmaria palmata cultivated in integrated multitrophic aquaculture across different seasons. Results showed marked seasonal and species-specific fluctuations. Porphyra exhibited the highest protein content, except in spring. Ulva was richer in lipids and magnesium across all seasons. Palmaria displayed lowest sodium-to-potassium ratios (<1), considered beneficial in reducing the risk of cardiovascular diseases. The distinct seasonal shifts in carbohydrate composition suggest each species adapts its polysaccharide metabolism. All species contained relevant essential amino acids and essential fatty acids contents. Red seaweeds showed high content of omega-3 eicosapentaenoic acid and phycobiliproteins, highlighting their functional potential. These findings demonstrate that seasonal variability shapes the nutritional and bioactive composition of seaweeds, offering opportunities to optimize biomass production for targeted applications.