Changes in cellular energy budget as a measure of whole effluent toxicity in zebrafish (Danio rerio)

Abstract

Organisms exposed to suboptimal conditions face an a priori cost of combating stress in terms of metabolic resources. The energy available for maintenance, growth, and reproduction, based on the biochemical analysis of the energy budget rather than on the direct measurement of those endpoints, may therefore provide a sensitive measure of stress in an organism. The aim of this study was to validate changes in energy budget as an ecologically relevant sublethal parameter by comparing these responses with physiological, growth, and reproductive endpoints. A toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to a control and 50, 75, and 100% effluent for 28 d under flow-through conditions. Effects of effluent exposure were measured as changes in glycogen, lipid, and protein budgets. Furthermore, the observed effects were linked to different processes like growth, condition, respiration, and reproduction within the same populations. Our results indicate that changes in lipid budgets in exposed fish were the most sensitive endpoint. Excellent relations were found between cellular energy budgets, relative condition factor, and respiration (r2 = 0.795, p < 0.001; and r2 = 0.735, p < 0.001, respectively), but relations were poorer for reproductive output (r2 = 0.410, p < 0.034). As a whole, especially changes in lipid energy budgets provide a sensitive and fast indicator of altered condition in zebrafish under the given exposure regime and allow linking cellular effects to other endpoints within the same exposed populations.

Chronic toxicity of the antiepileptic carbamazepine on the clam Ruditapes philippinarum

“…Under stress PROT content can either increase or decrease. Smolders et al (2003) reported that low to intermediate levels of pollution trigger increased protein synthesis (e.g. metabolic defenses involved in detoxification processes), but decreased protein synthesis was also referred, being attributed to high concentrations of pollutants (Smolders et al, 2004), when organisms cannot handle oxidative stress.…”

Multistress effects on goldfish (Carassius auratus) behavior and metabolism

“…Under stress, hepatic glycogen rapidly provides glucose, via glycogenolysis pathway, which supplies other organs readily usable energy (Moon and Foster 1995). Moreover, a decrease in lipid stores and the disruption of lipid metabolism were shown for several pollutants and fish species (Smolders et al 2003;Zheng et al 2013;Castelli et al 2014). Modification in the protein concentration results from a perturbation in the protein turnover, with an imbalance between the synthesis and the degradation rate of proteins (Smolders et al 2003).…”

“…Moreover, a decrease in lipid stores and the disruption of lipid metabolism were shown for several pollutants and fish species (Smolders et al 2003;Zheng et al 2013;Castelli et al 2014). Modification in the protein concentration results from a perturbation in the protein turnover, with an imbalance between the synthesis and the degradation rate of proteins (Smolders et al 2003). In the white muscle, proteins are the main source of energy.…”

Lethal and sublethal effects of oil, chemical dispersant, and dispersed oil on the ctenophore Mnemiopsis leidyi

“…If the former, it is unknown whether this was due to a reduction in mnemiopsin through protein degradation, loss through membrane damage, or a reduction in mnemiopsin synthesis as toxic exposure resulted in prioritizing other cellular functions such as repair and detoxification pathways (e.g. Camus et al 2003, Smolders et al 2003, Olsvik et al 2012. If mnemiopsin activity was affected, there may have been a reduction in binding or light production efficiency, either through direct toxic effects or indirectly (e.g.…”