Arginine/metabolism; Diet/veterinary; Dietary Supplements; Energy Metabolism; Polyamines/metabolism; Salmo salar/metabolism; Acetyltransferases/biosynthesis; Acetyltransferases/genetics; Acetyltransferases/metabolism; Adipose Tissue, White/enzymology; Adipose Tissue, White/growth & development; Adipose Tissue, White/metabolism; Animals; Aquaculture; Arginine/administration & dosage; Carnitine O-Palmitoyltransferase/biosynthesis; Carnitine O-Palmitoyltransferase/genetics; Carnitine O-Palmitoyltransferase/metabolism; Diet/adverse effects; Dietary Proteins/adverse effects; Dietary Proteins/metabolism; Enzyme Induction; Fish Proteins/biosynthesis; Fish Proteins/genetics; Fish Proteins/metabolism; Isoenzymes/biosynthesis; Isoenzymes/genetics; Isoenzymes/metabolism; Lipid Metabolism; Liver/enzymology; Liver/growth & development; Liver/metabolism; Muscle, Skeletal/growth & development; Muscle, Skeletal/metabolism; Ornithine/blood; Ornithine/metabolism; Ornithine Decarboxylase/biosynthesis; Ornithine Decarboxylase/genetics; Ornithine Decarboxylase/metabolism; Plant Proteins/adverse effects; Plant Proteins/metabolism; Putrescine/metabolism; Salmo salar/blood; Salmo salar/growth & development