APPARENT AND TRUE AVAILABILITY OF AMINO-ACIDS FROM COMMON FEED INGREDIENTS FOR ATLANTIC SALMON (SALMO-SALAR) REARED IN SEA-WATER

The average apparent and true availabilities of essential and non-essential amino acids to Atlantic salmon (Salmo salar) smolts reared in experimental conditions in seawater were: 87.7 and 94.3%; 81.9 and 90.7%; 82.7 and 89.3%; 73.0 and 84.9% for Norse-LT94, flame-dried herring, steam-dried herring, and menhaden fish meals, respectively. Average apparent and true amino acid availabilities were 77.9 and 91.9% for com gluten meal; 79.0 and 92.5% for canola meal; 56.8 and 79.4%, and 70.3 and 84.4% for soybean meal. Average apparent and true amino acid availabilities for a 50/50 mix of soybean meal and flame-dried herring mix were 67.4 and 80.3%, respectively. True availability values of amino acids were a better indication of biological value, specifically for those feed ingredients with relatively low protein content, such as plant sources. Use of true availability values of amino acids would allow more accurate and economical feed formulation.