Introduction
A seafood-based diet has been widely recognized as beneficial to human health. Yet, most European consumers do not meet the dietary recommendations of eating at least two portions of fish (equivalent to 300 g) per week to ensure the provision of essential nutrients (EFSA, 2015) . One third of global population has severe nutritional deficiencies, particularly iodine (I) , selenium (Se) and iron (Fe), which results in impaired endocrine, neurophysiological and immunological functions (Pinkaew and Karrila, 2015). The development of eco-innovative farmed fish with adequate levels of essential nutrients through fortification with sustainable natural marine resources (e.g. iodine-rich macroalgae and Se-rich yeast) represents a potential strategy to overcome worldwide nutritional deficiencies, but also to increase consumer confidence in farmed seafood products (Tocher, 2015 ). The present study aimed to evaluate the potential nutritional benefits associated with the consumption of tailor-made farmed gilthead seabream ( Sparus aurata) and common carp ( Cyprinus carpio ), fortified with macroalgae and Se-yeast enriched diets.
Material and methods
Three diets (1 control and 2 supplemented with different blends of I-rich macroalgae and Se -yeast) were tested for 3 months in each fish species, simulating a finishing diet period. At the end of the trial, fish were slaughtered following the typical commercial practices and fillets were collected without skin: one fillet was immediately stored ( “raw sample”) and the second fillet was steamed at 105 ºC for 15 minutes prior to storage ( “cooked sample”). Iodine, Se and arsenic (As) contents were determined by inductively coupled plasma mass spectrometer , whereas macro and trace elements were quantified by micro-Energy Dispersive X-Ray Fluorescence (Barbosa et al., 2020).
Results and Conclusions
Results showed that biofortification strategies through the incorporation of I-rich seaweed and Se-yeast in seabream and carp diets can improve the nutritional quality, enhancing I, Se and Fe levels. Yet, whereas fortified carp fillets presented higher content of I (over 100% increase), fortified seabream fillets presented higher content of Se (over 90% increase) compared to non-fortified ones . S teaming increased I and Se contents in fortified seabream fish fillets and decreased Cl, Fe and Ca contents . Elements True Retention (TR) values ranged from 60% (Ca) to 134% (I) and from 65% (Ca) to 125 % (I) in fortified and non-fortified seabream fillets, respectively . On the other hand, steaming increased Fe and Zn contents in fortified carp fillets but decreased K, Ca and As contents . TRs values ranged from 59% (As) to 128% (Fe) and from 64% (Ca) to 117% (Fe ) in fortified and non-fortified carp fillets, respectively . Interestingly, higher TR was observed for As in non-fortified fillets (91% in seabream and 72% in carp), compared to fortified fillets (87-88 % in seabream and 59-62% in carp). In terms of nutritional benefits, the consumption of 150 g of steamed fortified seabream provided higher contributions to the daily Adequate Intakes (AI) set for I (12%, 9% and 20% for adults, pregnant woman and children, respectively), Se (85%, 70% and over 100% for adults, pregnant woman and children, respectively) and Fe (over 100 % for all groups ). Similarly, steamed fortified carp provided increased contributions to the daily AI set for I (21%, 16 % and 35 % for adults, pregnant woman and children, respectively), Se (30%, 24 % and over 100% for adults, pregnant woman and children, respectively), Fe (over 100% for all groups) and Zn (38%, 28 % and 66 % for adults, pregnant woman and children, respectively). It is worth mentioning that the consumption of fortified fillets still yielded Se and Fe intakes below the Tolerable Upper Intakes (Se: up to 99% UL in seabream and up to 34 % UL in carp; Fe: up to 12% UL in seabream and 18% UL in carp). These findings highlight the benefits of developing eco-innovative fortified farmed fish, through sustainable, safe, and cost-effective feeds, as well as the benefits of steaming as a suitable cooking procedure for fish healthy human consumption.
Funding
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No.773400 (SEAFOODTOMORROW ). This output reflects only the author’s view and the European Union cannot be held responsible for any use that may be made of the information contained therein.
References
Barbosa, V., Maulvault, A.L., Anacleto, P., et al., 2020. Enriched feeds with iodine and selenium from natural and sustainable sources to modulate farmed gilthead seabream ( Sparus aurata) and common carp ( Cyprinus carpio ) fillets elemental nutritional value. Food and Chem. Toxicology, 140, 111330. doi: 10.1016/j.fct.2020.111330
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Pinkaew , S., Karrila , T.T., 2015. Key properties of iodine-, iron- and zinc- fortified fish cracker: effects of ambient shelf storage on iodine retention and quality indicators. Int. J. Fam. Ther . 50, 1979–1987. doi:10.1111/ijfs.12871
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