Sub-lethal effects of waterborne copper in early developmental stages of rainbow trout (Oncorhynchus mykiss)

Abstract

The aim of this work was to study the impact of copper during a sub-chronic exposure to environmental concentrations in the early life stages of rainbow trout (Oncorhynchus mykiss). Eyed-stage embryos of rainbow trout, at 265°D, were exposed in semi-static conditions to sublethal concentrations of CuSO4 up to the larval stage (528 °D) under laboratory-controlled conditions. During 3 weeks, they were exposed to the environmentally-realistic concentration of 2 µg/L Cu and to a 10-fold higher concentration, 20 µg/L Cu. Several biological (survival, hatching success, malformation, growth) and behavioral (swimming activity) and molecular endpoints (genotoxicity and gene transcription) were studied. Exposure to 20 µg/L Cu had an inhibitory effect on hatching and increased half-hatched embryos (25%). At the end of the exposure, no significant differences were observed in growth of the larvae exposed to the highest Cu concentration. However, larvae exposed to 2 µg/L Cu exhibited increased growth in comparison with non-exposed larvae. The percentage of malformed larvae was significantly higher for both copper conditions, with skeletal malformations being the most observed. Expression of several genes was evaluated in whole larvae using quantitative real-time PCR. Genes involved in detoxification (gst, mt1 and mt2) and in cell cycle arrest (p53) were significantly repressed in both copper conditions when compared to control. In addition, potential genotoxic effects on larvae were investigated by the comet assay on blood cells, but this test did not demonstrate any significant DNA damage on larvae exposed to copper. This study confirms the adverse effects of copper on early life stages of rainbow trout even at the lowest environmentally relevant tested concentration.

Impacts of chemical stress, season, and climate change on the flounder population of the highly anthropised Seine estuary (France)

“…The total protein concentration was measured on the diluted S9 fraction (1:50 v/v in ultrapure water) following the method of Lowry et al (1951) and using a BIO-TEK Synergy HT microplate reader. Lipid peroxidation (TBARS) was determined on S9 fraction using the method of Buege and Aust (1978) adapted to microplate readers (Weeks Santos et al 2019). TBARS levels were measured using a UV-spectrophotometer (Biotek Synergy HT) at 530 nm.…”

Characterization of the bioaccumulation and toxicity of copper pyrithione, an antifouling compound, on juveniles of rainbow trout

“…The rainbow trout ( O. mykiss ) is a model species whose life cycle and physiology are well documented, is easy to rear in the laboratory, and is particularly sensitive to many contaminants (Le Bihanic et al, 2014; Weeks-Santos et al, 2019). A few studies on metal PT toxicity have been done on the rainbow trout ( O. mykiss ) (Okamura et al, 2002; Yamada, 2006).…”