BIOCHEMICAL ADAPTATION OF JUVENILE CARP (CYPRINUS-CARPIO L) TO FOOD-DEPRIVATION

1. Food deprivation for 28 days leads to biochemical adaptation in juvenile carp which reduces their metabolism to a level corresponding to their energy deficit. 2. Starved carp have lower white muscle and liver RNA concentrations than fed carp. Their RNA/DNA quotients are therefore also lower, indicating protein synthesis restriction under food deprivation. 3. Food deprivation reduces the cell size of the liver, but not of white muscle. Liver cell size reduction is associated with a decrease in soluble and total protein concentrations (mg/mg DNA and protein/DNA respectively). 4. Energy saving reductions in enzyme activity are induced in intermediary hepatic metabolism. The activities of NADP+-specific dehydrogenases (G6PDH, 6PGDH, IDH, ME) implicated in lipogenesis and of the amino acid metabolism enzyme G1DH are greatly depressed after four weeks of food deprivation.