Screening of selected feedstuffs by sub-adult narrow clawed crayfish, Astacus leptodactylus leptodactylus Eschscholtz, 1823

• ADCCP of fish meal products fed to sub-adult crayfish varied from 83.2% to 87.2%.
• ADCCP of plant protein concentrates ranged from 82% to 85%.
• ADCCP of low-protein plant meals differed from 53.8% to 87.6%.
• A linear regression was observed among in vivo ADCCP and in vitro ADCCP.

Apparent crude protein (ADCCP), crude fat (ADCCF) and gross energy (ADCGE) digestibility coefficients of several typical and novel feedstuffs were determined to be employed in formulated diets of sub-adult crayfish (13.35 g). The tested feedstuffs included three fish meals, three terrestrial animal by-products, three plant protein concentrates, nine high protein plant meals and three low protein plant meals. ADCCP varied in different fish meals ranging from 83.2% for sardine fish meal to 87.2% for anchovy meal. ADCCP values for plant protein concentrates ranged from 82% for soy protein to 85% for wheat gluten meal. ADCCP was lower in low protein plant meals in comparison to high protein plant meals. ADCCP ranged from 53.8% for corn flour to 87.6% for spirulina meal. Fish meals (85.5%) and high-protein plant meals (81.2%) had significantly (p < 0.05) higher ADCGE compared to other feedstuffs. The hepatopancreas showed the significantly (p < 0.05) highest protease, lipase and carbohydrase activities with respect to gastric juice and intestine. A significant (p < 0.05) linear regression (r2 = 0.948) was observed among in vivo ADCCP of five feedstuff classes fed to crayfish and in vitro ADCCP. Based on these observations, we conclude that crayfish has the capacity to successfully utilize nutrients from a broad range of dietary ingredients including animal, single cell and in particular, plant matter.