Metabolic adaptations of oxidative muscle during spawning migration in the Atlantic salmon Salmo salar L.
The adaptability/plasticity of the highly oxidative red muscle in Atlantic salmon was demonstrated during spawning migration. Substrate concentrations and the enzymatic pathways of ATP production were examined in red muscle obtained from Atlantic salmon at different sites along their migratory route in the Exploits River, Newfoundland, Canada. Individuals were chronologically sampled from a seawater site, two sites upstream, and at spawning. The 20% decrease in salmon body weight during the later stages of migration was accompanied by large decreases (mg dry weight(-1)) in both glycogen (P < 0.01) and total muscle lipid (P < 0.01). In contrast, water content and protein concentration (mg dry weight(-1)) of the red muscle increased by 25 and 34%, respectively, at spawning. Enzymes of the glycolytic pathways demonstrated a significant (P < 0.001) decrease in maximal activity as migration proceeded whereas enzymes of the oxidative phosphorylation pathways, specifically the citric acid cycle enzymes, exhibited an increase (P < 0.001) in maximal activity at spawning. The antioxidant enzyme superoxide dismutase also demonstrated an increase (P < 0.001) in maximal activity during the latter stages of migration. These adaptations imply that the red epaxial muscle of Atlantic salmon has a more efficient means of oxidizing lipids, while minimizing free radical damage, during the later stages of migration and spawning, thereby potentially increasing post spawning survival.
Bombardier
E
E
Department of Kinesiology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada. ebombard@ahsmail.uwaterloo.ca.
Booth
R K
RK
Consulting Services, Lotek Wireless, Newmarket, ON, L3Y 7B5, Canada.
Green
H J
HJ
Department of Kinesiology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
McKinley
R S
RS
Canada Research Chair-Animal Science, The University of British Columbia, 4160 Marine Drive, West Vancouver, BC, V7V 1N6, Canada.
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000704:Analysis of Variance; D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001834:Body Water / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D006003:Glycogen / Q000378:metabolism; D050356:Lipid Metabolism; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000502:physiology*; D009523:Newfoundland and Labrador; D045483:Rivers; D020317:Salmo salar / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology; D013056:Spectrophotometry, Ultraviolet; D013482:Superoxide Dismutase / Q000378:metabolism; D015431:Weight Loss
D000255:Adenosine Triphosphate; D006003:Glycogen; D013482:Superoxide Dismutase