Effects of rearing temperature on growth, metabolism and thermal tolerance of juvenile sea cucumber, Apostichopus japonicus Selenka: critical thermal maximum (CTmax) and hsps gene expression

摘要

Effects of different rearing temperatures (16, 21 and 26 degrees C) on growth, metabolic performance and thermal tolerance of juvenile sea cucumber Apostichopus japonicus (initial body weight 7.72 +/- 0.96g, mean +/- SD) were investigated in this study. During the 40-day experiment, growth, metabolic performance, food intake and energy budget at different reared temperatures were determined. Sea cucumbers rearing at 16 degrees C obtained better growth (final body weight 11.96 +/- 0.35g) than those reared at 21 (10.33 +/- 0.41g) and 26 degrees C (8.31 +/- 0.19g) (P<0.05), and more energy was allocated for growth at 16 degrees C (162.73 +/- 11.85J g(-1)d(-1)) than those at 21(79.61 +/- 6.76J g(-1)d(-1)) and 26 degrees C (27.07 +/- 4.30Jg(-1)d(-1)) (P<0.05). Critical thermal maxima (CTmax) values of juvenile sea cucumbers reared at 16, 21 and 26 degrees C were 33.1, 34.1 and 36.6 degrees C, respectively, and the upregulation of hsps in sea cucumbers reared at 26 degrees C was higher than those acclimated at lower temperatures (16 and 21 degrees C), indicating that temperature acclimation could change the thermal tolerance of the sea cucumber, and CTmax and hsps were sensitive indicators of the sea cucumber's thermal tolerance.