Mortality was daily monitored. All animals were weighed
weekly,in order to determine the percent weight gain (WG) as
(Wt-Wi/Wi) x100, where Wi ¼ initial and Wt¼ body weigh at any
time of measurement. At the end of the 4th week of exposure, all
animals were sacrificed and abdominal muscle was dissected and
immediately freezed at -20 °C to further determine the level of
energy reserves. Due to the small size of juveniles, abdominal
muscle was pooled every 2–3 animals, from the same treatment
and cohort. Glycogen was extracted and quantified by the method
of Lo et al.(1970), suitable for small samples. Total proteins were
quantified according to Bradford (1976), adapted to juvenilesof
the studied species (Stumpf et al.,2014; Calvo et al.,2013). To
quantify lipids, the protocol proposed by Frings and Dunn(1970)
was followed.