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Apparent digestibility coe⁄cients (ADCs) for dry matter (ADC dm ) and crude protein (ADC cp ) of selected feed ingredients were determined in vivo for grouper using passive faeces collection (Guelph System). A reference diet (RF) and test diets (consisted of 70% RF and 30% test ingredient) with 1% Cr 2 O 3 as an inert indicator were used. An RF contained 45% protein, 10% fat and 15.7 kJ g À1 metabolizable energy. Three isonitrogenous and isocaloric diets, each contained a test ingredient (white ¢sh meal, white cowpea meal and ipil-ipil leaf meal), were used in a growth study based on ADC cp of feed ingredients. An RF without Cr 2 O 3 was a control. The ADC values of experimental diets were also determined. In grouper, the ADC dm of white cowpea meal, defatted soybean meal, wheat £our and shrimp meal (74^76%) were signi¢cantly lower than that of squid meal (99%), but comparable with those of the ¢sh meals (84^89%). No signi¢cant di¡erence was observed between the ADC dm of ipilipil leaf meal, rice bran and wheat £our (56^73%). The ADC cp of white cowpea meal and defatted soybean meal were similar to those of the ¢sh meals, squid meal and shrimp meal (94^99%). The ADC cp of wheat £our was comparable with that of ipil-ipil leaf meal (79^83%). Rice bran had the lowest ADC cp value of 43%. Based on speci¢c growth rate (SGR), the growth of ¢sh fed white cowpea meal-based diets was similar to that of the control ¢sh (3.23 .3% day À1 ). Also, no signi¢cant di¡erence was observed between the ADC dm (68^72%) and ADC cp (88^91%) of white cowpea meal-based diet and the control diet. The results suggest that ADC values can be used as indicators to determine the nutritional value of feed ingredients.White cowpea meal can be incorporated as a protein source in practical diet for grouper at 20.5% of the diet with no adverse e¡ect on growth.

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