Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon.
The objective of the current study was to investigate the effects of feed restriction on whole-organism upper thermal tolerance and the heat shock response of green and white sturgeon to determine how changes in food amount might influence physiological performance of each species when faced with temperature stress. Two parallel feed restriction trials were carried out for juvenile green (202g; 222-day post hatch: dph) and white sturgeon (205g; 197-dph) to manipulate nutritional status at 12.5%, 25%, 50%, or 100% of optimum feeding rate (100% OFR were 1.6% and 1.8% body weight/day, respectively) for four weeks. Following the trials, the critical thermal maximum (CTMax, 0.3°C/min) of sturgeon (N=12/treatment/species) was assessed as an indicator of whole-organism upper thermal tolerance. To assess temperature sensitivity, sturgeon (N=9/treatment/species) were acutely transferred to two temperature treatments (28°C and 18°C as a handling control) for 2h followed by 2h of recovery at 18°C before being sacrificed, and gill, brain, and mucus sampled for measurements of 70-kDa heat shock protein levels (Hsc/Hsp70). Feeding rate had species-specific effects on CTMax in green and white sturgeon such that CTMax of green sturgeon decreased as the magnitude of feed restriction increased; whereas, CTMax of white sturgeon did not change with feed restriction. Elevated temperature (28°C) and feed restriction increased Hsc/Hsp70 levels in the gill tissue of green sturgeon, while heat shock increased Hsc/Hsp70 levels in the mucus of white sturgeon. Our results suggest that green sturgeon may be more susceptible to temperature stress under food-limited conditions.
Department of Animal Science, University of California, Davis, CA 95616, USA.
Seunghyung
S
Lee
Department of Animal Science, University of California, Davis, CA 95616, USA.
Silas S O
SS
Hung
Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA.
Nann A
NA
Fangue
Department of Animal Science, University of California, Davis, CA 95616, USA.
Liran
L
Haller
Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA.
Christine E
CE
Verhille
Department of Animal Science, University of California, Davis, CA 95616, USA.
Juan
J
Zhao
Department of Animal Science, University of California, Davis, CA 95616, USA. Electronic address: todgham@ucdavis.edu.
Anne E
AE
Todgham
D000821:Animal Feed; D000818:Animals; D004435:Eating; D029941:Fish Proteins / Q000378:metabolism; D005399:Fishes / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018869:Heat-Shock Response / Q000502:physiology*; D013696:Temperature
D029941:Fish Proteins; D018840:HSP70 Heat-Shock Proteins
Critical thermal maximum; Heat shock proteins; Nutritional status; Stress tolerance; Sturgeon