Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Copper exposure alters the metabolism of the blue crab Callinectes sapidus submitted to osmotic shock Eliana Jaime de Menezes a , Bruno Pinto Cruz (Dr) a , Camila de Martinez Gaspar Martins (Dr) a,b , Fábio Everton Maciel (Dr) a,b, ⁎ a Programa de Pós-Graduação em Ciências Fisiológicas, Brazil b Instituto de Ciências Biológicas, Universidade Federal do Rio Grande – FURG, Av. Itália km 8, Campus Carreiros, 96201-900 Rio Grande, RS, Brazil ARTICLE INFO Keywords: Copper (Cu) Callinectes sapidus Crab Aerobic metabolism Osmotic shock ABSTRACT Copper (Cu) is an essential metal capable to alter many metabolic and physiological processes in animal species, depending on the environmental concentration and salinity. The present study evaluated the effects of Cu ex- posure on the metabolism of the blue crab Callinectes sapidus under different osmotic situations. Crabs were acclimated at two different salinities conditions (30 and 2). Subsequently, they were exposed to Cu during 96 h at each salinity and under hypo-osmotic shock. Results demonstrated that Cu exposure increased whole-body oxygen consumption. In addition, the activity of LDH decreased while citrate synthase increased in anterior gills from animals submitted to hypo-osmotic shock. This scenario indicates extra stress caused by sudden environ- mental osmotic changes, as commonly observed in estuarine environments, when combined with copper ex- posure. Therefore, the activity of LDH and citrate synthase enzymes might be sensitive indicators for aquatic toxicology studies approaching Cu contamination in estuarine environments. 1. Introduction Decapod crustaceans have been widely used as animal models for understanding the mechanisms underlying the osmoregulatory process, that usually takes place in their gills (Mantel and Farmer, 1983). Pre- vious studies have shown that low salinities usually induce an increase in metabolic rate of hyperosmoregulator animals due to increased en- ergetic consumption of ionic pumps (Lucu and Pavičić, 1995; Piller et al., 1995; Brown and Terwilliger, 1999). Brackish water decapods can tolerate a wide range of salinities by hyperosmoregulating at low and osmoconforming at high salinities (Engel, 1977; Gerard and Gilles, 1972; Lynch et al., 1973; Tagatz, 2006; Tan and van Engel, 2006). Recently, the Asian shore crab Hemigrapsus sanguineus was shown to be highly resistant to sudden salinity changes by combining discrete os- molality changes in hemolymph with an avoidance behavior of physi- cally moving to optimal salinity (Hudson et al., 2018). Another metabolic parameter affected by salinity changes in dec- apod crustaceans is the oxygen consumption. The blue crab Callinectes sapidus tends to decrease oxygen consumption as environmental salinity increases, and differences may occur depending on the season and gender (Engel and Eggert, 1974) and period of feeding (Curtis, 2009). Lower oxygen consumption was also observed as a response to high salinities in isolated gills of the crab Scylla serrata (Paital and Chainy, 2012). Recently, the same pattern of higher oxygen consumption at low salinities and lower oxygen consumption at high salinities was also reported in the shore crab Hemigrapsus crenulatus (Urzúa and Urbina, 2017). Several metals, such as iron (Fe), zinc (Zn), and Cu, are essential for aquatic organisms once these are involved in many cellular processes. Cu, besides composing the molecular structure of the respiratory pig- ment hemocyanin of some mollusks species, acts as a cofactor of en- zymes involved in several physiological processes of vertebrates and invertebrates (Ryu et al., 2003; Serafim and Bebianno, 2009; Suzuki et al., 2002), and is essential for respiration in all eukaryotic cells, al- though presents toxic effects at high concentrations (Chavez-Crooker et al., 2003). Once the physical-chemical characteristics of the water influence the toxicant effects of metallic pollutants, salinity fluctuations might directly affect metals bio-availability, including Cu, in the water (Bianchini and Gilles, 2000; Paquin et al., 2000). Generally, Cu ab- sorption by aquatic organisms occurs in the epithelial surfaces, such as gills membranes of fish and crustaceans (Grosell et al., 2007; Macrae et al., 1999; Paquin et al., 2002; Paquin et al., 2000). After absorption, https://doi.org/10.1016/j.marpolbul.2019.110743 Received 24 June 2019; Received in revised form 14 November 2019; Accepted 15 November 2019 ⁎ Corresponding author at: Universidade Federal do Rio Grande (FURG), Instituto de Ciências Biológicas (ICB), Av. Itália km 8, Campus Carreiros, 96.201-900 Rio Grande, RS, Brazil. E-mail address: maciel-fe@hotmail.com (F.E. Maciel). Marine Pollution Bulletin xxx (xxxx) xxxx 0025-326X/ © 2019 Elsevier Ltd. All rights reserved. Please cite this article as: Eliana Jaime de Menezes, et al., Marine Pollution Bulletin, https://doi.org/10.1016/j.marpolbul.2019.110743