Biochemical indicators of muscle growth in the snow crab Chionoecetes opilio (O. Fabricius).
This study examined the relationships between muscle growth rate, the activity of metabolic enzymes and the RNA:DNA ratio, in adult snow crabs Chionoecetes opilio. After moulting, crabs were assigned to three feeding rations to attain a range of tissue growth rates. Muscle growth rate, estimated by the variation in dry tissue content per ml of merus of the first walking leg, was positively correlated with changes in muscle cell number, as evaluated by the DNA content per ml of merus. However, no significant correlation was detected between growth rate and the variation in muscle cell size, the latter being estimated by the change in the protein:DNA ratio. This is due to the fact that, in starved crabs, a reduction in the number of cells is partly compensated by a size increment of the remaining ones. This phenomenon also weakened the overall relationship between muscle growth rate and the phosphofructokinase (PFK) capacity per ml of merus. The simple correlation between those two variables was significantly positive for animals which increased their mass of muscle but insignificant for those which were loosing muscle mass. The lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome c oxidase (CCO) capacity per ml of merus did not match growth rate. The significant simple correlations that were detected between growth rate and the various enzyme activity expressed per g of protein, per µg of DNA and per g of dry mass did not hold when partial correlations were computed. Variations in muscle cell size were related to adjustments in the quantity of RNA per cell, as depicted by the RNA:DNA ratio. Since muscle growth was not correlated with the variation in muscle cell size, it was not correlated with the RNA:DNA ratio either.
Mayrand
E
Département de Biologie, Université Laval, G1K 7P4, Québec, Canada
Guderley
H
Dutil
J