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

Abstract

Apparent crude protein (ADC CP ), crude fat (ADC CF ) and gross energy (ADC GE ) 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. ADC CP varied in different fish meals ranging from 83.2% for sardine fish meal to 87.2% for anchovy meal. ADC CP values for plant protein concentrates ranged from 82% for soy protein to 85% for wheat gluten meal. ADC CP was lower in low protein plant meals in comparison to high protein plant meals. ADC CP 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 ADC GE 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 (r 2 = 0.948) was observed among in vivo ADC CP of five feedstuff classes fed to crayfish and in vitro ADC CP . 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. • ADC CP of fish meal products fed to sub-adult crayfish varied from 83.2% to 87.2%. • ADC CP of plant protein concentrates ranged from 82% to 85%. • ADC CP of low-protein plant meals differed from 53.8% to 87.6%. • A linear regression was observed among in vivo ADC CP and in vitro ADC CP .