APPARENT AMINO-ACID AVAILABILITY AND PLASMA-FREE AMINO-ACID LEVELS IN SIBERIAN STURGEON (ACIPENSER BAERI)

Duplicate groups of Siberian sturgeon (Acipenser baeri) were fed one of three diets differing in protein source and in amino acid composition. Growth performance of fish, apparent digestibility coefficients, amino acid availabilities and plasma free amino acid concentrations were measured. Parameters of growth performance and feed utilization in sturgeon were significantly better (P < 0.01) with casein, or casein and soyabean-based diets than with the diet based on fishmeal. Apparent digestibility coefficients (ADC) of dry matter and protein were higher with diets containing casein and/or soybean than with a fishmeal-based diet. Amino acid availabilities were high, generally greater than 80% for most indispensable amino acids (IAA). Good correlations were found between plasma IAA concentrations and dietary available levers of IAA.