A seaweed extract containing laminarin (L) and fucoidan (F) (L/F) was manufactured from brown seaweed (Laminaria digitata) in spray-dried (L/F-SD) and wet (L/F-WS) forms. The effect of supplementation of pig diets with L/F-SD and L/F-WS (L, 500 mg/kg feed; F, 420 mg/kg feed) for 21 days pre-slaughter, on quality indices of fresh M. longissimus dorsi (LD) steaks was examined. Susceptibility of porcine liver, heart, kidney and lung tissue homogenates to iron-induced (1mM FeSO₄) lipid oxidation was also investigated. Dietary supplementation with L/F did not increase plasma total antioxidant status (TAS). In LD steaks stored in modified atmosphere packs (80% O₂:20% CO₂) (MAP) for up to 15 days at 4 °C, muscle pH, surface colour (CIE 'L*' lightness, 'a*' redness and 'b*' yellowness values) and microbiology (psychrotrophic and mesophilic counts, log CFU/g pork) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C>LF-SD>L/F-WS. A statistically significant reduction in lipid oxidation (P<0.05) was observed in LD steaks from 75% of pigs (n=6) fed with L/F-WS compared to controls. Iron-induced lipid oxidation increased in liver, heart, kidney and lung tissue homogenates over the 24h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue homogenates. Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.
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