Apparent digestibility coefficients of four feed ingredients for Synechogobius hasta

Apparent digestibility coefficients (ADCs) of dry matter, crude protein, lipid, energy, phosphorus and amino acids in white fish meal, soybean meal, rapeseed meal and peanut meal were determined for Synechogobius hasta (28.65 +/- 0.43 g, mean +/- SD), using a reference diet with chromic oxide indicator and test diets that contained 70% reference diet, by weight, and 30% of feed ingredients. The juvenile S. hasta were held in 300 L tanks at a density of 30 fish per tank respectively. Faeces were collected from three replicate groups of fish by siphoning. The ADCs of dry matter and energy were the highest in white fish meal and the lowest in rapeseed meal (P < 0.05). Crude protein ADC was the lowest in rapeseed meal (P < 0.05) and showed no significant differences among other treatments (P > 0.05). The highest phosphorus ADC was observed in white fish meal and differences were not marked for other treatments (P > 0.05). Lipid ADC were above 90% and showed no significant differences among the treatments (P > 0.05). Amino acid availability values for the test ingredients followed similar trend to values of protein digestibility. All amino acids were more available from fish meal than from plant protein ingredients. Among three plant meals, the availability of amino acids was higher in peanut meal and lower in rapeseed meal.