Ecological impact of macroalgae secondary metabolites on fatty acid and amino acid profiles of A. lixula sea urchin in the Mediterranean Sea

The introduction of non-native species into marine ecosystems can alter trophic interactions and influence the physiology of native organisms. Understanding these biochemical interactions is essential to assess the ecological impact of these species on local biodiversity. For the first time, the following study evaluates the effects of different macroalgae secondary metabolites on fatty acid and amino acid profiles of sea urchin Arbacia lixula (Linnaeus, 1758) from the Mediterranean Sea. The macroalgae involved in this study were Ericaria brachycarpa, an endemic species of the Mediterranean, and Asparagopsis taxiformis, an allochthonous invasive species. Gas chromatography-mass spectrometry (GC–MS) and gas chromatography-flame ionization detection (GC-FID) techniques were employed for the elucidation of the fatty acids, while amino acids were investigated by means of high-performance liquid chromatography coupled to fluorescence detector (HPLC-FLD). The impact of macroalgae metabolites on the fatty acids and amino acids in A. lixula species was evaluated after exposures at 24 and 48 h. Analytical results revealed that E. brachycarpa and A. taxiformis metabolites determined a significant change in levels of fatty acids (PUFAs, MUFAs, and SFAs) compared to untreated A. lixula species in accordance with their susceptibility to oxidation mechanisms. Also, macroalgae secondary metabolites induced distinct and time dependent metabolic reprogramming in A. lixula uncovering a biphasic oxidative stress response, membrane remodeling, and amino acids compensation mechanisms.