Changes in muscle of postmoult snow crabs Chionoecetes opilio ( O . Fabricius ) fed different

Somatic growth, muscle cell condition and metabolism, and gonadal production have been 21 21 studied in male snow crabs Chionoecetes opilio fed 0, 0.4 and 2 g ? animal ? day and sampled 5, 25, and 60 days after the terminal moult. Twenty-five days after moulting, muscle growth rate was low in crabs fed a high ration and negative in the other groups, and no gonadal production took place. This suggests that the energy was utilised in priority to sustain a high maintenance metabolism. Between 25 and 60 days post-moult, maintenance costs were apparently lower and more energy was directed, in decreasing order of priority, towards gonadal production, which was independent of food ration, muscle growth and reserve build-up in the digestive gland, the two latter being directly related to food ration. Starvation caused the death of merus muscle cells, as indicated by the significant decrease in DNA content, but after 60 days the size of the remaining cells (protein:DNA ratio) had increased as much as that of crabs fed a high ration. It may be a better strategy to maintain fewer cells, by using material and energy obtained from the sacrificed ones, than to keep all cells in a deficient state. Crabs fed a high ration filled the new larger exoskeleton through hypertrophy and hyperplasia. After 25 days of undernutrition, the reduced number of muscle cells relatively to the merus volume was counterbalanced by an enhanced activity of phosphofructokinase (PFK), citrate synthase (CS) and cytochrome C oxidase (CCO) per g of muscle dry weight. An inverse relationship between food ration and enzyme activity per g dry weight further attenuated the effect of food ration on the enzyme total activity in the whole merus muscle. After 60 days of starvation, the still high enzyme activity per g dry weight could no longer compensate for the continuing loss of cells and, at that time, the enzyme total activity was directly related to food ration. Our results suggest that the feeding status of wild crabs may affect their locomotor ability through effects on muscle capabilities.  2000 Elsevier Science B.V. All rights reserved. ́ *Corresponding author. Present address: Elise Mayrand, Universite de Moncton, Campus de Shippagan, 218 Boul. J.D. Gauthier, Shippagan, Nouveau-Brunswick, Canada, E8S 1P6. Tel.: 506-336-3425; fax: 506-3363477. E-mail address: [email protected]. (E. Mayrand) 0022-0981/00/$ – see front matter  2000 Elsevier Science B.V. All rights reserved. PI I : S0022-0981( 99 )00115-X 96 E. Mayrand et al. / J. Exp. Mar. Biol. Ecol. 243 (2000) 95 –113