Farming a wild seaweed and changes to its composition, bioactivity, and bioaccessibility: The Saccorhiza polyschides case study

The nutritional value, elemental and fatty acid composition as well as key biological activities were determined in a large brown seaweed species (Saccorhiza polyschides, abundant in European shores), taking into account the effects of wild vs farmed and land-based vs open sea Integrated Multi-Trophic Aquaculture (IMTA) system dichotomies. The results showed that S. polyschides has significant amounts of relevant nutrients, some biological activity (anti-inflammatory), high contents of the essential elements Se (1.07–1.79 mg/kg dw) and I (367–522 mg/kg dw), and a high bioaccessibility of I. However, As levels should be monitored, given their high bioaccessibility (∼60–70% range), and I levels may translate into excessive I intake if too much seaweed is consumed (if daily consumption of dried S. polyschides exceeds 3 g dw). Regarding the wild-farmed dichotomy, wild S. polyschides had a moderately higher nutritional value, including a better ω3/ω6 ratio, but a lower Se content than farmed S. polyschides, 0.80 ± 0.01 vs 0.58–0.69 and 1.07 ± 0.05 vs 1.16–1.79 mg/kg dw, respectively. Furthermore, bioaccessibility of elements was not much affected by cultivation. Concerning land-based vs open sea IMTA, in comparison to S. polyschides in earthen ponds, lower Hg and Pb contamination, but higher Cd levels were determined in the seaweed cultivated in open sea. S. polyschides farming per se did not have a large deleterious impact on the characteristics of this edible seaweed and may ensure the production of large amounts of algal biomass for feed, food, and nutraceutical applications.Highlights: S. polyschides had anti-inflammatory activity and high I content (367–522 mg/kg dw); As levels should be monitored, given their high bioaccessibility (∼60–70% range); Wild S. polyschides had a higher nutritional value, including a better ω3/ω6 ratio; Regarding land-based vs open sea IMTA, land-based seaweed had lower Cd levels; S. polyschides farming did not affect this seaweed and may enable scale-up.The experimental work was funded by the projects AQUAMAX (Ref.: 16-02-01-FMP-0047) and I9+ PROALGA (Ref.: 16-01-03-FMP-0011). Furthermore, experimental work related to seaweed cultivation and R. Quintã's contract at IPMA were funded by IntegraSea Project (European Union's Horizon 2020 programme under Marie Skłodowska-Curie grant agreement 800506).info:eu-repo/semantics/publishedVersio