Sustained Exercise Increases Plasma Growth Hormone Concentrations in Two Anadromous Salmonids

1988 ◽  
Vol 45 (4) ◽  
pp. 747-749 ◽  
Author(s):  
Bruce A. Barrett ◽  
Brian A. McKeown

Sustained exercise for 24 h at 1.5 body lengths per second (bl/s) resulted in a severalfold increase in the plasma growth hormone (GH) concentration of steelhead trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch). Peak levels occurred 10 min postexercise and returned to basal levels within 4 h of exercise termination. GH levels exhibited a steady increase after the fourth hour of exercise and peaked at 24 h. Individuals exercised for 48 h did not exceed plasma GH levels of the 24-h peak.

1988 ◽  
Vol 66 (4) ◽  
pp. 853-855 ◽  
Author(s):  
Bruce A. Barrett ◽  
Brian A. McKeown

During the increased locomotor activity of migration many salmonids do not actively feed and it is likely that metabolic alterations occur to facilitate the mobilization of stored reserves. The present laboratory study was designed to simulate the occurrence of exercise and starvation as natural parameters of migration and to assess the effects of such parameters on levels of plasma growth hormone, which might indicate alterations in metabolism during migration. Juvenile steelhead trout, Salmo gairdneri, were starved for a 30-day period. Starved individuals exhibited a marked increase in plasma growth hormone concentration (38.6 ± 6.7 ng/mL) compared with control individuals held on a normal feeding regime (6.4 ± 1.84 ng/mL). A subgroup of fish from the starved group were exercised by being forced to swim at 1.5 body lengths/s for a 24-h period. Exercised individuals exhibited plasma growth hormone levels in excess of 140 ng/mL. There was no significant difference between the plasma growth hormone levels of unexercised starved fish and exercised fed fish.


1973 ◽  
Vol 30 (6) ◽  
pp. 831-834 ◽  
Author(s):  
Gary Wedemeyer

A rapid (3 min) but sublethal temperature increase from 10 to 20 imposed a greater stress on juvenile coho salmon (Oncorhynchus kisutch) than on juvenile steelhead trout (Salmo gairdneri). Both species suffered hyperglycemia, hypocholesterolemia, increased blood hemoglobin, and decreased blood sugar regulatory precision, but the steelhead recovered more quickly. Acid–base equilibrium was essentially unaffected, and only the coho suffered any significant interrenal vitamin C depletion. Vitamin C normalization required about 24 hr.


1986 ◽  
Vol 64 (9) ◽  
pp. 2062-2063 ◽  
Author(s):  
R. M. Sweeting ◽  
B. A. McKeown

Plasma growth hormone levels were measured in coho salmon exposed to seawater to examine whether somatostatin has growth hormone release inhibitory action in salmon. Somatostatin (2 μg/10 g body weight) was injected prior to exposure to seawater and samples were taken 6 and 12 h postexposure. The results indicate that somatostatin does have potent growth hormone release inhibitory action in salmon, as it does in other teleosts.


1975 ◽  
Vol 32 (9) ◽  
pp. 1553-1559 ◽  
Author(s):  
R. A. Holt ◽  
J. E. Sanders ◽  
J. L. Zinn ◽  
J. L. Fryer ◽  
K. S. Pilcher

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.


1978 ◽  
Vol 35 (1) ◽  
pp. 8-11 ◽  
Author(s):  
J. E. Sanders ◽  
K. S. Pilcher ◽  
J. L. Fryer

Juvenile coho salmon (Oncorhynchus kisutch), sockeye salmon (O. nerka), and steelhead trout (Salmo gairdneri) were infected by intraperitoneal injection of a suspension of the causative organism of bacterial kidney disease at seven experimental temperatures from 3.9 to 20.5 °C. In coho salmon and steelhead trout percent mortality was maximal (78–100%) in the range of 6.7–12.2 °C. As the temperature increased above 12.2 °C mortality declined progressively; at 20.5 °C it was only 8–14%. The two highest temperatures had some suppressing effect on the disease, which was greatest at 20.5 °C. In sockeye salmon this was not apparent, as percent mortality was essentially 100% at all temperatures from 6.7 to 20.5 °C; this species appeared to be highly susceptible to the disease agent. Temperature also influenced the mean number of days between infection and death. This interval was shortest in all three species of salmonids at the higher temperatures, varying from 21 to 34 days at 15.0–20.5 °C. It increased progressively as temperature decreased below this range; at 6.7 °C it varied from 60 to 71 days among the three species. Key words: bacterial kidney disease, temperature, salmonids, Corynebacterium, coho salmon, sockeye salmon, steelhead trout


1972 ◽  
Vol 29 (2) ◽  
pp. 167-171 ◽  
Author(s):  
W. S. Zaugg ◽  
L. R. McLain

The average Na+- and K+-stimulated adenosinetriphosphatase (ATPase) activity of microsomes from gills of hatchery-reared coho salmon (Oncorhynchus kisutch) increased from about 12 μmoles ATP hydrolyzed/mg protein per hr during February through mid-April to approximately 24 in mid-May. Larger fish developed higher activities than smaller fish. Hatchery-reared spring chinook salmon (O. tshawytscha) exhibited a similar increase 2–3 weeks earlier.In 2-year-old hatchery-reared steelhead trout (Salmo gairdneri), Na+-, K+-ATPase activities were elevated in some, but not all, smolt-appearing animals. Parr-appearing fish, including maturing males, showed no activity increase. When held in fresh water to July, steelhead smolts lost their silvery color and became more parr-like in appearance, and the previously elevated ATPase activity decreased to near pre-smolt levels. Yearling steelhead held at the laboratory showed a more consistent rise in ATPase activity.The increase in transport ATPase (Na+-, K+-stimulated) activity occurring during parr–smolt transformation is probably a preparatory step for saltwater adaption and may also be closely associated with migratory disposition.L'activité moyenne de l'adénosinetriphosphatase (ATPase) stimulée par Na+ et K+ dans les microsomes des branchies de saumons coho (Oncorhynchus kisutch) élevés en pisciculture augmente de 12 μmoles environ d'ATPase hydrolysée/mg de protéine par h de février à la mi-avril à 24 à la mi-mai. Les gros poissons développent une activité plus grande que les petits. Les saumons chinook de printemps (O. tshawytscha) élevés en pisciculture font preuve d'un accroissement semblable deux à trois semaines avant les saumons coho.


1989 ◽  
Vol 46 (2) ◽  
pp. 232-242 ◽  
Author(s):  
S. Swales ◽  
C. D. Levings

Off-channel ponds in the upper reaches of the Coldwater River, British Columbia, were major rearing areas for juvenile coho salmon (Oncorhynchus kisutch). Chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Salmo gairdneri), and Dolly Varden char (Salvelinus malma) were generally scarce in the ponds, although they were numerous in the main river. Coho salmon were predominant at "natural" river sites while steelhead trout was the main species at sites with "rip-rap" bank stabilization. Catches of juvenile coho were much lower in the main river than in the ponds where they were the main species, and were more variable in the river. Population density and biomass estimates of juvenile coho in the ponds ranged from 0.100 fish∙m−2 and 1.00 g∙m−2 to 1.00 fish∙m−2 and 5.15 g∙m−2, compared with density estimates of 0.08–0.23 fish∙m−2 in the river. The coho population in the ponds consisted of 0+ and 1+ age-groups in similar proportions, while in the main river the 0+ age-group was much more abundant. The growth rate of coho in the ponds was faster than in the main river, with pond fish reaching mean lengths of 62–79 mm at the end of the first growing season, compared with 53 mm in the main river. Smolt outmigration from the main study pond occurred in late spring with peak outmigration in May and June coinciding with peak river discharge and increasing water temperatures in the main river and pond.


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