Long-term effect of a short pulse of dietary supplementation with algae on the quality of turbot (Scophthalmus maximus) frozen fillets

• Published in: Frontiers in Marine Science
• Main Authors: Sáez, M. Isabel, Galafat, Alba, Vizcaíno, Antonio J., Rodríguez, Cristina, Hernández de Rojas, Alma, Alarcón, F. Javier, Martínez, Tomás F.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2022
• Subjects: Scophthalmus maximus; Turbot
• Online Access: http://dx.doi.org/10.3389/fmars.2022.957217; https://www.frontiersin.org/articles/10.3389/fmars.2022.957217/full

This study raises the question of the potential long-term effects of a feeding pulse with diets containing algal biomass on the quality of frozen turbot ( Scophthalmus maximus ) fillets. A feeding trial was carried out with this aim, in which juvenile turbot were fed during 60 d with six different experimental diets, two of which were enriched with the macroalgae Ulva rigida (U diets), the other two with a microalgae blend (M diets), plus a non-supplemented control diet (CT), and finally, a commercial aquafeed (COM). Two inclusion levels were considered in algae-enriched diets (50 and 100 g kg -1 ) so that they were designed as U5 and U10 for U. rigida , and M5 and M10 for microalgae-enriched diets. The duration of the feeding pulse with the functional diets was 60 days, and then, all specimens were fed with a COM diet for a further 150-d period until reaching a body size close to the commercial standard (approximately 750 g). Subsequently, fish were sacrificed; fillets were removed from the pigmented flank and kept at -20 °C for 5 months. Then, fillets were thawed and the muscle proximal composition and fatty acid profile were analyzed, and fillet quality parameters were assessed during a 10-d co\ld storage period at 4°C. The possible deferred effects of algae-enriched diets on fillet quality were compared with a control diet without algae (CT) and with a commercial diet (COM). Roughly, the results obtained indicated that a 60-d administration pulse of algae-enriched diets induced some long-term changes in both the nutritional and organoleptic quality of turbot fillets. In this regard, the algae-enriched aquafeeds improved the muscle antioxidant response throughout the cold storage period, prolonging the shelf life of thawed turbot fillets. In addition, in terms of consumers’ acceptability, this feeding pulse on pre-growing stage of the productive cycle was able to modify the skin and muscle pigmentation of fish of commercial size. Namely, the U10 diet increased the protein content, improved muscle texture, ...