Trace metals in six fish by-products of two farmed fishes, the gilthead sea bream (<i>Sparus aurata</i>) and the meager (<i>Argyrosomus regius</i>): Interactions with the environment and feed

Abstract

For the large producers of farmed fish, the utilization of fish by-products as ingredients of food is important and thus their characterization, in terms of chemical composition and safety, becomes necessary. In this study, eleven trace metal concentrations in by-products (head, gills, guts, trimmings, bones and skin) of two Mediterranean farmed fishes, the gilthead sea bream (Sparus aurata) and the meager (Argyrosomus regius) were determined by ICP-MS. According to overall concentrations, the sequence of trace metal levels in decreasing order was Fe > Zn > Mn > Cu > As > Cr > Pb > Ni > Cd > V>Co. Higher median concentrations (μg g−1 d.w.) of As were determined in bones and guts (2.16 and 2.04), Cd, Co, Cu, Pb in guts (0.175, 0.058, 16.3, 0.381), Cr in skin and bones (1.51 and 1.45), Ni in guts and skin (0.231, 0,218), Fe and Mn in gills (50.1, 16.8) and V in trimmings (0.052). Trace metal levels determined in fish feed were considerably lower compared to EC limits (Directive 2002/32/EC). The highest bioconcentration factor (BCF) values were calculated for Cd, Ni, Pb in muscle, for Fe, Mn, Zn in gills, for Cd, Co, Cu, Zn in guts and for Cr in bones. Exploitation of fish by-products as additives in food industry appears feasible, based on the concentrations of metals examined.