Yield, nutrients uptake and lipid profile of the halophyte Salicornia ramosissima cultivated in two different integrated multi-trophic aquaculture systems (IMTA)

Abstract

The nutrient removal, biomass production and nutritional value of the halophyte Salicornia ramosissima were evaluated in the context of an Integrated Multi-Trophic Aquaculture (IMTA) system. The experiment consisted of an indoor fish RAS whose effluent was used to feed two different halophyte hydroponic systems: a Nutrient Film Technique (NFT) system or a Deep Water Culture (DWC) system. The highest yield of S. ramosissima was observed in the DWC (320 g m−2 day−1), this system showed significantly higher yields compared to the NFT. Both hydroponic systems were effective in removing nutrients from the fish RAS wastewater, contributing to the wastes valorization process. Maximal nutrient uptake efficiencies were: 82.8% and 68.6% NO3− in the DWC and the NFT, respectively; 72.6% PO43− in the DWC and 82.9% in the NFT; 63.6% NO2− in the DWC vs 56.4% in the NFT; and 89.2% NH4+ in the DWC vs 94.1% in the NFT. The lipid profile of the halophytes in the DWC was analysed. The total lipid content ranged from 2.99% to 3.83%. The fatty acids (FA) profile in the leaves was dominated by polyunsaturated fatty acids (about 66%), which were represented by α-linolenic acid (41%) and linoleic acid (24%), followed by saturated fatty acids (28%) with palmitic acid (22%) as the major component. A small component of monounsaturated fatty acids accounts for about 12% of total FA. Regarding lipid classes, pigments were the most abundant compounds followed by glycolipids, phospholipids, flavonoids and sterols. The study supports the potential of S. ramosissima to valorise aquaculture wastes and its high nutritional interest. The experimental systems minimized waste and maximized resources utilization. Such integrated approaches can contribute to the sustainability and resilience of aquaculture systems while providing additional economic opportunities through the production of high value halophyte products.