Optimization of feed formulation for mature female striped bass

To optimize the essential amino acid (EAA) profile for mature striped bass Morone saxatilis, diets with graded levers of three essential amino acids-l ysine (Lys), threonine (Thr), and total sulfur amino acids (Tsaa) methionin e and cysteine-were fed to 4-year-old striped bass females. The relative co ncentrations of these EAAs were maintained in ratios similar to those deter mined from the analysis of striped bass skeletal muscle, (i.e., 2.2:1.1:1.0 [Lys:Thr:Tsaa]). All other dietary EAAs were maintained above the requirem ent levels published for juvenile striped bass. Three diets with graded lev els of Lys, Thr, and Tsaa were fed to mature female striped bass for II wee ks. Statistical analysis of weight gain, specific growth weight (percent pe r day), and feed conversion ratio (weight of feed fed/weight gained) indica ted significant differences (alpha = 0.05) among treatments. However, there were no significant differences in whole-body proximate composition, egg s ize, or gonadosomatic index among fish fed the three dietary treatments. Th e results of this experiment suggest that the dietary amino acid profile re quired for optimal growth and feed efficiency in mature female striped bass is similar to the requirement profile for juvenile striped bass.