Comparative toxicity of cadmium in the commercial fish species Sparus aurata and Solea senegalensis

Abstract

The induction of metallothionein-like proteins (MTLPs) as well as cadmium levels (Cd) was studied in tissues of gilthead sea bream Sparus aurata and flatfish Solea senegalensis after an intraperitoneal (i.p.) injection of cadmium (2.5 mg kg−1 body weight). The liver, gills, intestine and blood of S. aurata as well as the liver and intestine of S. senegalensis were collected for analysis at 0, 3 and 6 days after the injection. Cd levels significantly increased in all tissues of the treated animals, and the highest accumulation was found in the liver in both species (p<0.05). Cadmium administration provoked significant inductions of MTLP synthesis in the liver and intestine of S. aurata (p<0.05), while no increase in these protein levels was recorded in tissues of S. senegalensis. Our findings imply that MTLP synthesis in S. aurata probably led to an enhanced ability to cope with the toxicant, whereas the MTLP induction in S. senegalensis was inhibited by the accumulated cadmium, as reflected by the mortality rate of this species. Under the experimental conditions, hepatic MTLPs appear to be a good indicator of the Cd level in S. aurata; however, no link was found between the cadmium concentration and MTLP induction in S. senegalensis, which suggests that MTLPs did not play a main role in detoxification by metal sequestration.