Effects of Exercise Training on the Performance, Growth, and Protein Turnover of Rainbow Trout (Salmo gairdneri)

1987 ◽  
Vol 44 (9) ◽  
pp. 1614-1621 ◽  
Author(s):  
D. F. Houlihan ◽  
P. Laurent

Rainbow trout (Salmo gairdneri) that were made to swim continuously at 1 body length/s for 6 wk had double the growth rate of tank-rested control fish. The endurance to fatigue at a range of swimming velocities of these trained animals was significantly better than that of the controls. Measurement of the rate of protein synthesis in the tissues was carried out by the free pool flooding technique. Protein degradation rates were calculated from the difference between synthesis and net protein accretion. In controls and trained animals the fractional rates of protein synthesis and degradation were ranked gills > ventricle > red muscle > white muscle whereas the efficiencies of conversion of protein synthetised into protein retained as growth were in the reverse sequence. Synthesis rates in three of the four tissues of the trained animals were approximately double those of the control animals. Calculated degradation rates of proteins also increased in the trained animals; the increased growth rates resulted from the proportionately greater increase in the rate of synthesis. The rate of synthesis decreased to control levels once the trained animals ceased swimming.

1987 ◽  
Vol 57 (2) ◽  
pp. 269-277 ◽  
Author(s):  
T. Muramatsu ◽  
Y. Aoyagi ◽  
J. Okumura ◽  
I. Tasaki

1. The effect of starvation on whole-body protein synthesis and on the contribution of protein synthesis to basal metabolic rate was investigated in young chickens (Expt 1). Strain differences between layer and broiler chickens in whole-body protein synthesis and degradation rates were examined when the birds were starved (Expt 2).2. In Expt 1, 15-d-old White Leghorn male chickens were used, while in Expt 2 Hubbard (broiler) and White Leghorn (layer) male chickens at 14 d of age were used. They were starved for 4 d, and heat production was determined by carcass analysis after 2 and 4 d of starvation. Whole-body protein synthesis rates were measured on 0, 2 and 4 d of starvation (Expt 1), and on 0 and 4 d of starvation (Expt 2).3. The results showed that starving reduced whole-body protein synthesis in terms of fractional synthesis rate and the amount synthesized. Whole-body protein degradation was increased by starvation both in terms of fractional synthesis rate and the amount degraded on a per kg body-weight basis.4. Reduced fractional synthesis rate of protein in the whole body was accounted for by reductions in both protein synthesis per unit RNA and RNA:protein ratio.5. In the fed state, whole-body protein synthesis and degradation rates, whether expressed as fractional rates or amounts per unit body-weight, tended to be higher in layer than in broiler chickens. In the starved state, the difference in the rate of protein synthesis between the two strains virtually disappeared, while the degradation rates were higher in layer than in broiler birds.6. Based on the assumed value of 3.56 kJ/g protein synthesized (Waterlow et al. 1978), the heat associated with whole-body protein synthesis in the starved state was calculated to range from 14 to 17% of the basal metabolic rate with no strain difference between layer and broiler chickens.


1985 ◽  
Vol 230 (1) ◽  
pp. 117-123 ◽  
Author(s):  
R M Palmer ◽  
P A Bain ◽  
P J Reeds

Tyrosine balance and protein synthesis were studied during the same incubation in isolated rabbit forelimb muscles. From these measurements, protein degradation was calculated. Isolated muscles were usually in a state of negative amino acid balance, principally as a result of the 75% decrease in protein synthesis. Muscles from rabbits starved for 18 h had lower rates of both protein synthesis and degradation compared with muscles from normally fed rabbits. Intermittent mechanical stretching and the addition of insulin at 100 microunits/ml increased rates of both protein synthesis and degradation. Increases in the rate of protein synthesis were proportionately greater in the muscles from starved animals. In muscles from both fed and starved donors, increases in protein-synthesis rates owing to intermittent stretching and insulin were proportionately greater than the increases in degradation rates. For example, insulin increased the rate of protein synthesis in the muscles from starved donors by 111% and the rate of degradation by 31%. Insulin also increased the rate of protein synthesis when added at a higher concentration (100 munits/ml); at this concentration, however, the rate of protein degradation was not increased. The suppressive effect of insulin on high rates of protein degradation in other skeletal-muscle preparations may reflect a non-physiological action of the hormone.


1998 ◽  
Vol 55 (6) ◽  
pp. 1534-1544 ◽  
Author(s):  
Scott D Reid ◽  
T K Linton ◽  
J J Dockray ◽  
D G McDonald ◽  
C M Wood

Protein synthesis, net accretion, and degradation in liver, gill, and white muscle and ribosomal translational efficiency and protein synthesis capacity in liver and gill were measured using a flooding dose of [3H]phenylalanine in juvenile rainbow trout (Oncorhynchus mykiss). The fish were chronically exposed (90 days) in hardwater to the presence or absence of sublethal ammonia (70 µmol total ammonia ·L-1) alone or in combination with a 2°C elevation in the normal temperature profile over the months of June-September 1993 (ambient temperature range 13-22°C). Chronic sublethal exposure to ammonia had little impact on gill protein synthesis and degradation (protein turnover) and even less in muscle. However, in the liver, both protein synthesis and degradation were stimulated following 60 days of the sublethal ammonia exposure. The 2°C elevation in temperature resulted in a slight increase in protein turnover in both gills and liver. However, during the period of peak water temperature, the 2°C elevation in temperature inhibited protein dynamics in these tissues. Overall, elevated environmental ammonia in combination with a summer global warming scenario would challenge the ability of fish to adapt to alterations in the quality of their environment, most notably during periods of peak temperatures.


1986 ◽  
Vol 251 (5) ◽  
pp. C727-C736 ◽  
Author(s):  
M. S. Parmacek ◽  
N. M. Magid ◽  
M. Lesch ◽  
R. S. Decker ◽  
A. M. Samarel

Assessment of cardiac protein metabolism in thyroxine-induced left ventricular hypertrophy requires measurements of both protein synthesis and degradation. In vivo protein degradative rates can best be measured as the difference between rates of protein synthesis and growth. Accordingly, rates of left ventricular protein accumulation were determined in growing rabbits, and in animals administered intravenous L-thyroxine (200 micrograms X kg-1 X day-1) for up to 15 days. Left ventricular protein fractional synthetic rates in euthyroid and thyroxine-treated rabbits were measured by continuous infusion of [3H]leucine (200 mu Ci/h X 6 h), and results converted to milligrams protein synthesized and degraded per day. Thyroxine administration produced left ventricular hypertrophy by increasing the rate of total protein synthesis (35.7 +/- 2.0, 71.0 +/- 7.0, and 62.6 +/- 4.0 mg of left ventricular protein synthesized per day for 0-, 3-, and 9-day, thyroxine-treated rabbits, respectively). However, the increased rate of total protein synthesis was greater than the measured rate of total protein accumulation (8.1 vs. 15.9 mg protein/day for euthyroid and thyroxine-treated animals), indicating that left ventricular protein degradative rates were increased as well. These studies indicate that accelerated proteolysis may be important in the molecular and architectural remodeling of the rapidly hypertrophying heart during thyrotoxicosis.


1979 ◽  
Vol 178 (3) ◽  
pp. 725-731 ◽  
Author(s):  
R D Conde

The effect of hypophysectomy on the protein metabolism of the liver in vivo was studied. Fractional rates of protein synthesis and degradation were determined in the livers of normal and hypophysectomized rats. Synthesis was measured after the injection of massive amounts of radioactive leucine. Degradation was estimated either as the balance between synthesis and accumulation of stable liver proteins or from the disappearance of radioactivity from the proteins previously labelled by the injection of NaH14CO3. The results indicate that: (1) hypophysectomy diminishes the capacity of the liver to synthesize proteins in vivo, mainly of those that are exported as plasma proteins; (2) livers of both normal and hypophysectomized rats show identical protein-degradation rates, whereas plasma proteins are degraded slowly after hypophysectomy.


1988 ◽  
Vol 255 (6) ◽  
pp. C754-C759 ◽  
Author(s):  
R. J. McAnulty ◽  
L. H. Staple ◽  
D. Guerreiro ◽  
G. J. Laurent

Unilateral pneumonectomy in rats causes compensatory growth of the remaining lung. This growth involves rapid production of collagen and noncollagen proteins, but the mechanisms for these changes have not been fully investigated. Rates of collagen metabolism were measured using previously validated in vivo methods. Six days after pneumonectomy, a threefold increase in the fractional rate of collagen synthesis was observed (control 11.8 +/- 0.9%/day, pneumonectomy 30.0 +/- 4.6%/day). Collagen degradation rates also increased but returned to normal more rapidly than the synthesis rates. These changes in synthesis and degradation resulted in a 75% increase in collagen content by 28 days. Although degradation of extracellular collagens was apparently increased, the fraction degraded intracellularly decreased by approximately 30%. Noncollagen protein synthesis and degradation rates both increased by approximately 80% (control 44.3 +/- 3.4%/day, pneumonectomy 80.3 +/- 10.2%/day) with a slightly greater increase in synthesis that led to an 85% increase in noncollagen protein content 28 days after pneumonectomy. The data obtained show dramatic changes in protein synthesis and degradation during compensatory lung growth and indicate extensive remodeling of structural elements in lung tissue. The changes for intracellular collagen degradation provide further evidence that this pathway may have an important role in regulating collagen deposition.


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