Digestibility of extruded peas, extruded lupin and rapeseed meal in rainbow trout (Oncorhynchus mykiss) and turbot (Spetta maxima)

Apparent digestibility coefficients ADC. of nutrients and energy of extruded peas, extruded lupin and rapeseed meals were determined in juvenile rainbow trout and turbot. Extruded lupin was found to be a promising substitute for fish meal in the diets of trout and turbot, with an acceptable digestibility of its dry matter 70% in trout and 81% in turbot. and a high digestibility of its protein 96% in trout and 98% in turbot. and its energy 77% in trout and 85% in turbot.. Extruded peas had a lower digestibility of its protein in trout 88%. than in turbot 92%., and the ADC of energy, mainly supplied as starch, was relatively low 69% in trout and 78% in turbot.. The digestibility of rapeseed meal was improved by a thermal treatment. Without thermal treatment, rapeseed meal had a low digestibility of its dry matter 57%. and energy 69%. in turbot. The availability of phosphorus was higher for extruded lupin 62% in trout and 100% in turbot. compared to the other plant-ingredients. When compared to a solvent-extracted meal, the availability of phosphorus from rapeseed meal was improved by heat treatment in both species 42% vs. 26% in trout and 65% vs. 49% in turbot.. q2000 Elsevier Science B.V. All rights reserved