Halophytes like Salicornia ramosissima are valuable sources of biomass that can be grown in regions where traditional crops may not thrive. The green tips of S. ramosissima are utilized as a food product, whereas the rest of the plant is treated as residue. To establish a more sustainable and profitable production cycle, the residue must be valorized into by-products, which can be used in feed formulations, reducing reliance on traditional feed sources, and promoting more sustainable practices within the aquaculture industry. The current study aims to assess the feasibility of using S. ramosissima aerial by-products, as a substitute for wheat, in aquafeed formulations for juvenile stages of European sea bass, Dicentrarchus labrax, and whiteleg shrimp, Penaeus vannamei, evaluating RGR (% day-1), FCR, FI (% ABW day-1), Survival (%) and nutrient apparent digestibility coefficient (ADC = 100 − 100 × (% yttrium in feed / % yttrium in feces) × (% nutrient in feces / % nutrient in feed).
Four experimental diets were tested in triplicate for D. labrax: a commercial like diet (CTRL) and three experimental diets containing lignified S. ramosissima at 2.5 %, 5 % and 10 % inclusion levels. European sea bass juveniles (mean wet weight 7.3 g) were kept at 22 ± 0.5 ºC and fed ad libitum for 62 days. Five experimental diets were tested in quintuplicate for P. vannamei: a commercial like diet (Control), two experimental diets containing lignified S. ramosissima stems and two containing lignified S. ramosissima leaves and seeds, both at 5 % and 10 % inclusion levels. P. vannamei juveniles (mean wet weight 6.1 g) were kept at 28 ± 0.5 ºC and fed ad libitum for 55 days. At the end of the trial, fish and shrimp were weighted and counted for growth performance and survival determination. Additionally, feces samples were collected and analyzed to determine the ADC of the experimental diets.
No significant differences in RGR, FCR, FI or survival were observed among treatments for D. labrax. Nevertheless, P. vannamei fed diets containing S. ramosissima presented significantly higher FCR and FI values (table 1). These results can be explained by the significantly lower ADC of dry matter, lipids and energy observed, especially in the diet containing 10 % of S. ramosissima leaves and seeds.
The use of S. ramosissima by-products in aquaculture feeds presents a promising opportunity for the industry to enhance its sustainability and reduce its environmental impact. However, to fully comprehend the potential benefits and challenges of this approach, further research and development is necessary.
Acknowledgements: This work was supported by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 862834 (project AQUACOMBINE). This output reflects the views only of the authors, and the European Union cannot be held responsible for any use which may be made of the information contained therein.