Techniques for evaluation of dietary protein quality for the rainbow trout ( Salmo gairdneri)

Selection of the test fish for uniformity of body weight allowed bioassays for protein quality to be conducted within a 3-week period with small numbers of fish. Slope-ratios from the linear responses of body weight gain to graded levels of protein intake gave practical comparisons of the quality of protein sources. The use of different dietary concentrations of protein sources under test may indicate responses to factors other than those associated with protein per se. The slope-ratio technique lends itself to simultaneous estimations of the relative efficiency of protein energy utilization, which are important in evaluation of plant protein concentrates.