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Being a rich source of important nutrients, including highly digestible proteins, vitamins (A, D3), trace minerals (iodine, selenium) and n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA), fish consumption is generally regarded as part of a healthy dietary pattern. Exogenous feeding in aquaculture unlocks the possibility to tailor fish composition with healthy valuable nutrients. However, the use of supplements in the fish feed during fish production may undermine consumers' perception opinion of these fortified products. The effectiveness success of a functional food is a combination of its efficacy and meeting consumers' expectations. A self-administered questionnaire was designed to assess consumers' preferences regarding fish consumption, and their perception of farmed seabream as a functional food. A high consumption rate of fish, (between daily, and a minimum of three times a week), was reported by 47% of the respondents. Freshness, flavour, quality and price were the four most valued attributes. Good acceptance of the fish fortification concept was observed (53%), as well as positive receptiveness to its consumption (50%). Anti-oxidants and omega-3 fatty acids were the most accepted compounds for fish fortification. Additionally, two consumer groups were established based on their high (HIG) or low (LIG) interest in fish origin (wild vs aquaculture). The LIG was more receptive to all aspects of fish fortification and showed willingness to buy and consume it. This suggests that fortified fish could be targeted to the LIG profile group, which represents 42% of the studied population. With appropriate communication, farmed fish may be a good candidate for functional food. PROMAR Program (Portugal) [31-03-05-FEP-0060] FEDER fundsEuropean Union (EU) COST Action Feed for Health [FA 0802] FCT doctoral grant, Portugal [SFRH/BD/73452/2010]

Fish and seafood consumption are increasing worldwide and the contribution of aquaculture products to consumers' diets is significant. External feeding in aquaculture unlocks the possibility of tailoring fish products with health beneficial compounds. A study was undertaken to evaluate the feed fortification with an iodine rich macroalgae (Laminaria digitata) and selenised yeast, at its maximum permitted levels, on minerals and vitamins content in rainbow trout edible part. Dietary supplementation resulted in a six-fold increase for iodine and a 2.9-fold increase for selenium contents in trout fillets without altering sensorial traits. The fortified fish presented a nutritional contribution of 12.5% DRI for iodine and 78% DRI for selenium, but all produced fish could supply 80% DRI for vitamin D3. Overall, fish from this trial could be labelled as "high in selenium and high in vitamin D3" under the EFSA definition for a functional food. (C) 2016 Elsevier Ltd. All rights reserved. AQUAIMPROV - Programa Operacional Regional do Norte [SAESCTN-PIIDT/1/2011, NORTE-07-0124FEDER-000038] Lallemand Animal Nutrition (France) [ALKOSEL R397]

To test how iodine and both iodine and selenium supplementation affected the thyroid status as well as growth and survival in Senegalese sole, larvae were reared in a recirculation system from 15 to 34 DAH. Sets of three tanks were assigned to each of the following three diets: control (C), iodine (I) and iodine and selenium (I + Se). Samples were collected at 15, 27 and 34 DAH to determine dry weight, iodine and selenium levels, GPx and ORD activities, thyroid hormone levels and thyroid follicles histology. At 34 DAH, fish from the control (C) treatment suffered from hyperplasia of the thyroid follicles (goitre), whereas iodine-treated larvae did not (I and I + Se). Lower survival rates in the C groups were probably a consequence of the hyperplasia. Moreover, there was an improvement in thyroid hormone status in I- and I + Se-treated larvae, showing that further supplementation of live feed with iodine can be crucial for fish at early life stages, as it seems to sustain normal larval development, when reared in a recirculation system. Selenium did not affect the results. Together with previous results, this indicates selenium supplement is more important at younger life stages.

To study the effect of dietary supplementation of iodine in Solea senegalensis, larvae were randomly distributed in six tanks. Larvae in three tanks were given rotifers and Artemia enriched with iodine in addition to Rich Advance or Super Selco from 2 days after hatch (DAH) until 31 DAH. Larvae in a second set of three tanks were fed control rotifers and Artemia, enriched only with Rich Advance or Super Selco. Samples were collected at 2, 5, 10, 15 and 31 DAH to determine dry weight, total length, myotome height and thyroid status. Larvae fed the iodine-enriched diet had significantly higher weight at 31 DAH and higher levels of whole body iodine concentration, compared to control larvae. At 31 DAH, larvae from the control treatment showed typical goitrous thyroid follicles. Thyroid cells of larvae from this treatment appeared columnar or afollicular, with the colloid partly or completely depleted, representative of hyperplasia (goitre). The lower growth rate in fish larvae from the control treatment was possibly a consequence of the hyperplasia, and the iodine enrichment prevented Senegalese sole larvae from developing goitre. This study demonstrates the importance of iodine enrichment of live feed for fish reared in a recirculation system.

A 12-week performance trial was undertaken to evaluate the effects of a concomitant replacement of fishmeal and fish oil in a practical diet for gilthead seabream with a complementary mixture of vegetable proteins (soy, peas, corn and wheat) and oils (soybean, rapeseed), in terms of growth performance, feed utilization, apparent digestibility of nutrients and soluble nitrogen (N) and phosphorus (P) excretion. Fifteen homogenous groups of 50 seabream each (mean initial body weight: 180.7 ± 0.4 g) were stocked in 1000-L tanks and fed one of five experimental extruded diets formulated to be isonitrogenous, isolipidic and isoenergetic. A control diet (CTRL) was formulated with practical ingredients to contain 48% protein, 20% fat and 23 kJ/g energy. Two other diets were formulated in order to replace 40 and 60% of fishmeal by increasing levels of selected plant-protein ingredients (PP40FO and PP60FO, respectively). Based on these two last diets, two others were formulated in which fish oil was replaced at a 65% level by a mixture of soy and rapeseed oils (PP40VO and PP60VO). Growth of seabream, expressed either as weight gain or daily growth index was not significantly affected by the replacement at either 40 or 60% of fishmeal by plant-protein sources. At 40% fishmeal replacement level, the further replacement of 65% of fish oil by vegetable oils had no effect on growth performance. However, the concomitant replacement of 60% fishmeal and 65% replacement of fish oil caused a slight reduction in weight gain, but essentially a significant decrease in feed efficiency (FE). Proximate composition of fish was not affected by the various dietary treatments. Replacement of both fishmeal and fish oil had no significant effects on daily deposition of N, fat or P. Soluble P excretion was significantly reduced by the use of plant protein-rich diets. Growth performance of gilthead seabream during the grow-out phase was sustained by a practical dietary formulation containing as little as 13% of marine-derived proteins.