Food Shortage Causes Differential Effects on Body Composition and Tissue-Specific Gene Expression in Salmon Modified for Increased Growth Hormone Production.
Growth hormone (GH) transgenic salmon possesses markedly increased metabolic rate, appetite, and feed conversion efficiency, as well as an increased ability to compete for food resources. Thus, the ability of GH-transgenic fish to withstand periods of food deprivation as occurs in nature is potentially different than that of nontransgenic fish. However, the physiological and genetic effects of transgenic GH production over long periods of food deprivation remain largely unknown. Here, GH-transgenic coho salmon (Oncorhynchus kisutch) and nontransgenic, wild-type coho salmon were subjected to a 3-month food deprivation trial, during which time performance characteristics related to growth were measured along with proximate compositions. To examine potential genetic effects of GH-transgenesis on long-term food deprivation, a group of genes related to muscle development and liver metabolism was selected for quantitative PCR analysis. Results showed that GH-transgenic fish lose weight at an increased rate compared to wild-type even though proximate compositions remained relatively similar between the groups. A total of nine genes related to muscle physiology (cathepsin, cee, insulin-like growth factor, myostatin, murf-1, myosin, myogenin, proteasome delta, tumor necrosis factor) and five genes related to liver metabolism (carnitine palmitoyltransferase, fatty acid synthase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, glucokinase) were shown to be differentially regulated between GH-transgenic and wild-type coho salmon over time. These genetic and physiological responses assist in identifying differences between GH-transgenic and wild-type salmon in relation to fitness effects arising from elevated growth hormone during periods of long-term food shortage.
USDA-ARS, Hagerman Fish Culture Experiment Station, 3059F National Fish Hatchery Road, Hagerman, ID, 83332, USA.
Jason
J
Abernathy
INRA, UR1067 Nutrition Metabolism Aquaculture, F-64310, Saint-Pée-sur-Nivelle, France.
Stéphane
S
Panserat
USDA-ARS, Hagerman Fish Culture Experiment Station, 3059F National Fish Hatchery Road, Hagerman, ID, 83332, USA.
Thomas
T
Welker
INRA, UR1067 Nutrition Metabolism Aquaculture, F-64310, Saint-Pée-sur-Nivelle, France.
Elisabeth
E
Plagne-Juan
Fisheries and Oceans Canada, 4160 Marine Drive, West Vancouver, BC, Canada, V7V 1N6.
Dionne
D
Sakhrani
Fisheries and Oceans Canada, 4160 Marine Drive, West Vancouver, BC, Canada, V7V 1N6.
David A
DA
Higgs
Fisheries and Oceans Canada, 4160 Marine Drive, West Vancouver, BC, Canada, V7V 1N6.
Florence
F
Audouin
Fisheries and Oceans Canada, 4160 Marine Drive, West Vancouver, BC, Canada, V7V 1N6.
Robert H
RH
Devlin
USDA-ARS, Hagerman Fish Culture Experiment Station, 3059F National Fish Hatchery Road, Hagerman, ID, 83332, USA. Ken.Overturf@ars.usda.gov.
Ken
K
Overturf
D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001823:Body Composition / Q000235:genetics / Q000502:physiology; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D015870:Gene Expression / Q000235:genetics / Q000502:physiology*; D013006:Growth Hormone / Q000096:biosynthesis* / Q000235:genetics; D008099:Liver / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D017684:Oncorhynchus kisutch / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
D013006:Growth Hormone
Coho salmon; Gene expression; Liver; Metabolism; Muscle; Network analysis; Oncorhynchus kisutch; Proximate analysis; Transgenic