Effects of acclimation temperature regime on the thermal tolerance, growth performance and gene expression of a cold-water fish, Schizothorax prenanti

Abstract

Acclimation temperature is crucial for the optimization of a condition in aquaculture; we experimentally investigated the effects of temperature acclimation on the thermal tolerance, growth performance and gene expression levels of heat shock proteins (hsp70), growth hormone (gh) and insulin-like growth factors (igf-1) in Schizothorax prenanti, a cold-water fish in the Yangtze River basin. Critical thermal maximum (CT_max), critical thermal minimum (CT_min), lethal thermal maximum (LT_max), lethal thermal minimum (LT_min), feeding intake (FI), feeding efficiency (FE), and specific growth rate (SGR) were assessed at three stable temperatures (17, 22 and 27 °C) and one variable temperature (22 ± 5 °C) for 28 d. Better growth performance was observed under variable treatment compared to stable treatments. However, fish under the 27 °C treatment exhibited much weaker growth performance than those in the 17 °C treatment. Fish under variation temperature treatment fed like those under 22 °C treatment; the fish exhibited similar SGR but a higher gh and hsp70 level under variation temperature treatment. This may be due in part to a trade-off energy expenditure to deal with the temperature fluctuation. Together, these findings suggest that juvenile Schizothorax prenanti are resilient to daily fluctuations within the temperature tested here.

Keywords: Growth; Schizothorax prenanti; Temperature; Thermal tolerance.