Evaluation of apparent digestibility coefficients of individual feed ingredients in spotted rose snapperLutjanus guttatus(Steindachner, 1869)

Abstract

Apparent digestibility coefficients (ADCs) for dry matter, crude protein, energy and essential amino acids for five commonly used feed ingredients were determined for juvenile spotted rose snapper Lutjanus guttatus (average body weight 90.6 g). ADCs were determined using the stripping technique to collect faeces after fish were fed a reference diet and test diets composed of 700 g kg−1 reference diet and 300 g kg−1 test ingredient. Chromic oxide (Cr2O3) was used as an inert indicator. Ingredients tested included sardine fishmeal (FM), canola meal (CM), tuna by-products meal (TBM), poultry by-product meal pet grade (PBM-PG) and solvent-extracted soybean meal (SBM). In general, all ingredients showed high digestibility values for all essential amino acids, although differences were detected among ingredients. ADC values for dry matter, protein and energy ranged 77.0–80.4%, 84.3–82.5% and 89–88.8%, respectively, for marine ingredient and land-based animal protein sources, and 75.0–74.2%, 81.5–80.9% and 87.4–86.8%, respectively, for the plant-based protein source. SBM, TBM and PBM-PG should be further evaluated in feeding trials as partial FM replacements in rose snapper L. guttatus diets. Knowledge of ADC values for these ingredients will allow feed producers to develop nutritionally balanced, low-cost feed formulations for this species.