Metabolomic Insights into Wild and Farmed Gilthead Seabream (Sparus Aurata): Lipid Composition, Freshness Indicators, and Environmental Adaptations

Background/Objectives: This study explores the metabolic adaptations and quality differences between wild and farmed gilthead seabream (Sparus aurata), with a particular focus on lipid composition and metabolite profiles. These differences are examined in the context of varying environmental conditions, feeding regimes, and post-harvest processes. High-resolution magic-angle-spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was employed to perform the metabolomic analysis. Results: Farmed seabream exhibited higher lipid content and PUFA levels (e.g., DHA and EPA) due to aquaculture diets, while wild seabream showed lower lipid concentrations and elevated levels of polar metabolites. Metabolic trade-offs in wild seabream reflected greater physical activity and environmental adaptation. The K-value indicated faster spoilage in farmed seabream, particularly from Greece, linked to handling conditions. HR-MAS provided precise, reproducible results, allowing direct quantification of key metabolites without altering sample integrity. Methods: HR-MAS NMR was employed to analyze muscle tissue from wild and farmed seabream (produced in Spain and imported from Greece), providing high-resolution spectra without requiring sample extraction. Metabolite quantification included polyunsaturated fatty acids (PUFAs), creatine, taurine, lactate, and trimethylamine N-oxide (TMAO). Freshness was monitored using the K-value index, calculated from ATP derivative levels in samples stored at 4 °C. Conclusions: The study highlights the influence of diet and environment on the metabolic profiles of seabream. HR-MAS NMR emerges as a robust method for metabolomic studies and freshness assessment. Findings emphasize the potential for dietary adjustments to optimize aquaculture practices and fish quality while underscoring the importance of sustainable production strategies. Further research into lipid metabolism genes and environmental factors is recommended to deepen understanding of these adaptations.