Apparent digestibility of proteins,amino acids and phosphorus of seven feed ingredients for bluntnose black bream

The apparent digestibility(AD) of dry matter,protein,amino acids and phosphorus of seven feed ingredients for bluntnose black bream(Megalobrama amblycephala Yih) were determined by using 0.5%Cr2O3 as an indicator.The test diets consisted of 70% basal diet and 30% test feed ingredients,including fish meal,meat and bone meal,soybean meal,peanut meal,cottonseed meal,distillers dried grains with solubles(DDGS) and rapeseed meal.The fish averaging(296.54±1.71) g were reared in indoor aquarium tanks(3.0 m ×0.8 m ×0.8 m),and the fecal samples were collected by abdominal pressure method after five weeks.The results showed that apparent digestibility of dry matter,protein,amino acids and phosphorus of seven feed ingredients were 53.65%-77.48%,78.66%-93.63%,80.12%-94.83% and 3.21%-48.02%,respectively.Among the seven feed ingredients,the highest apparent digestibility of protein and total amino acids was in rapeseed meal;then the apparent digestibility of fish meal was close to that of peanut meal and soybean meal;and the lowest was in meat and bone meal.Apparent digestibility of phosphorus was the highest in DDGS,and the lowest in rapeseed meal and meat and bone meal,and others were 11.81%-29.10%.In conclusion,rapeseed meal,soybean meal,peanut meal can be used as high quality plant protein source to serve as alternative fishmeal for bluntnose black bream in production.The apparent digestibility of protein of DDGS was higher than that of meat and bone meal,and the apparent digestibility of phosphorus was the highest in seven feed ingredients.Therefore,DDGS can be used as a high quality fish feed ingredient.