Protein digestibility differed among fish meals and
ranged from 90% for fair and average quality menhaden meal
to 97% for anchovy meal. Protein apparent digestibility
coefficients (ADCs) in plant concentrates ranged from a low
of 89%for rice protein concentrate to a high of 100%forwheat
gluten meal. Apparent protein digestibility was lower in plant
meals than fish meals with a low of 70% for flaxseed meal to
a high of 89% for soybean meal. Low-protein plant meals had
generally lower proteinADCfrom64%for rice bran to 85%for
wholewheat.Asimilar pattern for energyADCswas observed;
ADCs ranged from 106% for anchovy meal to 32% for whole
wheat. In the current trial, divergent protein and energy ADC
values were obtained most notably in ingredients known to be
high in fiber or have very high starch content. The comparability
of ingredients/diets processed by cold pelleting or
extrusion thus appears questionable at this juncture