Metabolic effects of the expression of a phosphoglucomutase locus in the liver of rainbow trout

1990 ◽  
Vol 68 (7) ◽  
pp. 1499-1504
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann ◽  
Fred W. Allendorf ◽  
Kathy L. Knudsen
Keyword(s):  
Oxygen Consumption ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
White Muscle ◽  
Metabolic Effects ◽  
Parallel Analysis ◽  
Separate Experiment ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Consumption Rates ◽  
Sib Families

We examined the lengths, weights, condition factors, and hepatosomatic indices of juvenile rainbow trout (Oncorhynchus mykiss) from four full-sib families, each segregating at the temporal regulatory locus Pgm1-t, and the concentrations of RNA, DNA, and protein in their livers and white muscle. In three families, fish with phosphoglucomutase-1 (PGM1) activity in liver (Pgm1-t(b) fish) are significantly longer than their full-sibs lacking activity for liver PGM1 (Pgm1-t(a) fish). Hepatosomatic indices tend to be higher in the Pgm1-t(b) fish than in their Pgm1-t(a) siblings. RNA/DNA ratios in the liver of Pgm1-t(b) fish are significantly higher than those of Pgm1-t(a) fish in two families and marginal in a third. However, no significant differences were detected in a parallel analysis of nucleic acids and protein in white muscle, where PGM1 is expressed in all fish. In a separate experiment, Pgm1-t(b) fish were significantly heavier in all five families, had significantly higher condition factors in two families, and had marginally lower standardized oxygen consumption rates in three families.

RNA/DNA ratios in white muscle as estimates of growth in rainbow trout held at different temperatures

1990 ◽  
Vol 68 (7) ◽  
pp. 1494-1498 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
White Muscle ◽  
Specific Growth ◽  
Fish Size ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Different Temperatures ◽  
Specific Growth Rates ◽  
Rna And Dna

The concentrations of RNA, DNA, and protein in white muscle from 240 uniquely tagged rainbow trout (Oncorhynchus mykiss) held at three temperatures (5, 8 (control), and 11 °C) were measured. Both RNA and RNA/DNA ratios were better predictors of recent length- and weight-specific growth rates than they were of absolute fish size. Furthermore, RNA concentrations were better predictors of growth than RNA/DNA ratios. The strength of the regression between either RNA/DNA ratio or RNA and growth rate did not differ consistently among temperatures. Fish reared at warmer temperatures had lower concentrations of RNA for both a given growth rate and a given DNA concentration compared with cold-reared trout. Warm-reared fish also had lower concentrations of DNA and higher protein/DNA ratios than cold-reared trout when fish size was standardized. The concomitant decrease in both RNA and DNA concentrations resulted in marginally lower RNA/DNA ratios in warm-reared fish.

Influence of low temperature acclimation on fate of metabolic fuels in rainbow trout (Oncorhynchus mykiss) hearts

1993 ◽  
Vol 71 (11) ◽  
pp. 2167-2173 ◽  
Author(s):  
John R. Bailey ◽  
William R. Driedzic
Keyword(s):  
Oxygen Consumption ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Temperature Acclimation ◽  
Experimental Conditions ◽  
Intracellular Lipids ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Significant Difference ◽  
Precipitate Protein ◽  
Fuel Source

Rainbow trout (Oncorhynchus mykiss) were acclimated to 5 and 20 °C. Oxygen consumption of isolated perfused hearts was measured at 5 or 15 °C with either glucose or palmitate as the exogenous fuel source. With glucose as the fuel there was no significant difference in oxygen consumption of hearts from either acclimation group at either temperature. With palmitate as the fuel source, hearts from fish acclimated to and tested at 5 °C had significantly higher oxygen consumption than hearts from fish acclimated to 20 °C and tested at either 5 or 15 °C. Hearts from fish both acclimated to and tested at 5 °C had a higher oxygen consumption with palmitate than when glucose was supplied. This reflects the preference for fatty acid fuels found in cold acclimated muscle tissue, and consequently the amount of oxygen required to utilize fats. Under all experimental conditions, 14CO2 production from either (6-14C)glucose or (1-14C)palmitate could account for less than 0.5% of oxygen consumption. Tissue chemical analysis showed that most of the label from (6-14C)glucose appeared in acid-soluble (glycolytic intermediates, citric acid cycle intermediates, amino acids, etc.) and lipid fractions while most of the label from (1-14C)palmitate appeared in lipid- or acid-soluble or acid precipitate (protein material) fractions. This indicates considerable dilution of exogenous fuels in endogenous pools, which could account for the discrepancy in measured O2 consumption and 14CO2 production. Glucose catabolism was little affected by either acute or chronic changes in temperature other than an increase in glucose incorporation into the glycogen pool. Hearts from fish both acclimated to and tested at 5 °C showed an increased handling of exogenous fatty acids as reflected by elevated rates of catabolism and incorporation into intracellular lipids.

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