Production Systems

Thermal imprinting modifies bone homeostasis in cold challenged sea bream (Sparus aurata, L.)

“…In the LHT and HT groups, a cold challenge caused a significant (P<0.05) downregulation of ocn transcripts in vertebrae compared with the same group maintained at 23±1°C. Comparison of gene expression in vertebrae from cold-challenged LT, HLT, LHT and HT fish with the LT group at 23±1°C (the temperature frequently used for larval culture; Mozes et al, 2011) revealed significant (P<0.05) downregulation of transcripts for ocn in the HT fish and ogn1 in the LT and LHT fish. ).…”

“…1A). The temperature regimes were selected considering the two extreme temperatures of the optimal range for early life development of gilthead sea bream (18 and 22°C) (Baeverfjord et al, 2010;Mozes et al, 2011): (i) 18°C from egg incubation through to hatching and up until larvae-juvenile transition (LT); (ii) 22°C from egg incubation through to hatching and up until larvae-juvenile transition (HT); (iii) 18°C from egg incubation up until hatching and then 22°C until larvae-juvenile transition [low-high temperature (LHT)]; (iv) 22°C from egg incubation through to hatching and then 18°C up until larvae-juvenile transition [high-low temperature (HLT)]. All treatment groups of juvenile fish were then maintained for 7 months in duplicate 2 m 3 tanks per group, in a semi-closed recirculating seawater system with 5-10% water renewal each week, under a constant water temperature regime (21-22°C).…”

“…Relative expression levels were calculated by dividing the detected copy number of the target genes by the reference gene. Results are expressed as log 2 foldchange and were calculated relative to the control group, which was defined as the experimental animals obtained from larvae maintained at 18°C from egg until the larvae-juvenile transition, because this is the temperature regime frequently used for gilthead sea bream larval rearing (Mozes et al, 2011). The comparisons made and the strategy for statistical analysis is indicated below.…”

“…Fish are ectotherms and their body temperature is in equilibrium with the external thermal conditions (Mozes et al, 2011). This means that changes in ambient water temperature directly affect the cell cycle, metabolism, membrane fluidity and, at the molecular level, influence transcription, translation, post-translational processing and protein structure (Somero, 2010).…”

“…The overall effect of temperature is apparent as an overt change in whole animal physiology such as growth rate, feeding rate and body composition (Clarke and Johnston, 1999;Greene and Selivonchick, 1987;Wang et al, 1987;Wiegand et al, 1988). Temperature therefore plays a determinant role in fish physiology, biology and ecology, and is a driver of seasonal responses (Mozes et al, 2011;Somero, 2005). Gilthead sea bream (Sparus aurata) is eurythermal and in the wild is exposed to a broad range of ambient water temperatures (11-26°C), and behavioural thermoregulation allows them to avoid temperature extremes (Davis, 1988).…”