The gilthead seabream is the most important Mediterranean aquacultured fish
species. The main objective of this study was to investigate whether copper
sulphate bath treatments used routinely in aquaculture have effects on
important physiological functions of early life stages of the gilthead
seabream (Sparus aurata). Fingerlings (80–90 days, 0.27 ± 0.06 g) were exposed to
copper sulphate baths at 0, 0.25, 0.5 and 1.5 mg L−1 during 24 h.
Effects on the central nervous function were evaluated analysing brain
acetylcholinesterase activity (AChE). Oxidative stress was assessed by the
quantification of lipid peroxidation (LP). Heat shock proteins (HSP70) were
used as a general response to chemical stress, RNA/DNA ratio as an indicator
of growth, and effects on detoxification function were estimated using
glutathione–S-transferases activity (GST). Exposure of S. aurata fingerlings to
copper sulphate induced increased lipid peroxidation. In contrast, there
were no significant changes in AChE activity, HSP70 levels, RNA/DNA ratio or
GST activity. Particularly, the absence of response in GST activity points
towards a limited extent of the putative damage caused by the treatments at
the highest doses (evidenced through the levels of peroxidation), since this
enzyme is directly implicated in detoxification processes involving redox
cyclic products. The results suggest that copper sulphate baths at the
conditions tested are safe treatments for S. aurata fingerlings.