CHANGES IN PLASMA AND MUSCLE FREE AMINO-ACIDS IN ATLANTIC SALMON (SALMO-SALAR) DURING ABSORPTION OF DIETS CONTAINING DIFFERENT AMOUNTS OF HYDROLYZED COD MUSCLE PROTEIN

1. Atlantic salmon (Salmo salar) were fed three diets of increasingly pre-digested protein for 4 weeks. They were then starved for 2 days, then fed to satiation. 2. Plasma and muscle samples were collected before feeding and 0, 6, 12, 24, 48 and 72 hr after feeding and analysed for free amino acids. 3. Plasma essential free amino acids were significantly higher (P < 0.05) at 6 and 12 hr post-prandial, while the non-essential amino acids were hardly affected. 4. Minor differences were obtained in muscle free amino acids. Maximum concentration was obtained at 24 hr post-prandial in fish fed the control, and at 12 hr post-prandial for both the pre-digested feeds. 5. In both plasma and muscle, total free amino acids were higher in those fed the proteolysed feeds than in those fed the non-proteolysed feed.