Evaluation of practical diets containing different protein levels, with or without fish meal, for juvenile Australian red claw crayfish ( Cherax quadricarinatus)

Abstract

Six practical diets containing increasing percentages of crude protein (CP) (30%, 35%, and 40%) with or without anchovy fish meal (FM) were fed to juvenile red claw crayfish (mean individual weight=1.12 g) during an 8-week feeding trial. Growth, survival, feed conversion ratio, and amino acid composition of tail-muscle meat of juvenile red claw were determined. At the conclusion of the experiment, specific growth rate (SGR) and percent survival among treatments, which averaged 3.91%/day and 80.7%, overall, were not significantly different among treatments. The percent weight gain of red claw fed a diet containing 20% fish meal and 40% crude protein was significantly higher (1352%) than that of red claw fed a diet containing 0% fish meal and 30% crude protein (828%), but not different from red claw fed all other diets. Red claw fed Diet 3 had significantly higher FCR (5.73) compared to red claw fed Diet 6 (3.03) but not different from red claw fed the other four diets. Results from this study indicate that juvenile red claw can be fed a practical diet containing 35% CP with 0% FM if a combination of less expensive plant protein ingredients (SBM, wheat, BGY, and milo) is added. CP levels can be reduced to 30% if 15% anchovy fish meal is included. Reducing CP levels and the reliance of fish meal in Australian red claw diets may help reduce operating costs and thereby increase producers profits.