Effects of chemical stress and food limitation on the energy reserves and growth of turbot, Scophthalmus maximus

Abstract

The objective of the present study is to examine the growth and energetic performance of juvenile turbot after exposure to contaminated sediment and during the subsequent recovery period with or without food limitation. We designed a two-step experiment by first exposing juvenile turbot to harbour sediment for 26 days and then transferring them to clean sea water with different frequencies of feeding for 35 days. Without food limitation, fish previously exposed to contaminated sediment compensated for weight, length and lipid reserve losses; we did not record any differences in size, Fulton's K condition index and triacylglycerol/sterol (TAG/ST) ratio after the 35-day depuration period compared to the reference fish. This result could be related to the compensatory growth mechanism observed in a wide range of fish species following a period of growth depression. With food limitation during the 35-day depuration period, recovery growth was not sufficient to restore length and weight values similar to the reference fish. Moreover, turbot previously exposed to contaminated sediment and subsequently fed twice or once a week exhibited extremely low TAG/ST ratios, but the reference fish submitted to the same restrictive feeding conditions did not. This study indicates that juvenile fish affected by chemical pollution can improve their biological performance if pollution events are followed by a period of abundant food. However, if pollution events occur during periods of food scarcity, e.g. in winter, storage of energy reserves will be compromised.

Influence of feeding frequency on diurnal variations in liver and muscle RNA/DNA ratios in Misgurnus anguillicaudatus

“…In past research on other organisms, the RNA/DNA ratio was measured as the RNA/DNA ratio variation in muscle tissue, but variations in liver tissue and the correlation of diurnal variations between hepatic and muscle tissues have seldom been reported (Kerambrun et al., 2014; Ji et al., 2016). Thus, some questions must be answered.…”

“…Some studies have shown that the RNA/DNA ratio is related to not only the growth of aquatic animals (Tong et al., 2010) but also their nutrition status; consequently, the RNA/DNA ratio is a useful indicator of an organism's nutritional status. Recently, some studies have shown that the RNA/DNA ratio is a reliable and sensitive indicator of nutrient stress in organisms (Desai & Anil, 2002; Ji, Liu, Song, & Yang, 2016; Zehra & Khan, 2015), and the ratio has been applied to evaluate the nutritional status of organisms, including fish (Buckley, 1984; Kerambrun, Henry, Rabhi, & Amara, 2014; Liang, Wang, & Chen, 2001; Wang et al., 2008), crustaceans (Anger & Hirche, 1990) and aquatic reptiles (Ji, Xie, Liu, Li, & Yang, 2017; Ji et al., 2016).…”

Fish as Reference Species in Different Water Masses

“…Physiological condition indices are useful tools to assess the effect of pollution on fish when variation in other environmental factors is limited. In a recent study, Kerambrun et al (2014) examined the growth and energetic performance of juvenile turbot after exposure to contaminated sediment and after a recovery period of 35 days in clean seawater with or without food limitation. In a recent study, Kerambrun et al (2014) examined the growth and energetic performance of juvenile turbot after exposure to contaminated sediment and after a recovery period of 35 days in clean seawater with or without food limitation.…”