Apparent digestibility of eight unconventional feed ingredients for Megalobrama amblycephala

The apparent digestibility(AD) for dry matter,protein,crude fat,amino acids,phosphorus and energy of eight feed ingredients for bluntnose black bream Megalobrama amblycephala Yih were determined.The feed ingredients included expanded feather meal,enzyme feather meal,blood meal,silkworm pupa,corn gluten meal,broken rice,corn,and barley grain.Test diets consisted of 70% reference diet and 30% test feed ingredients,and added 0.5%Cr2O3 as an indicator.The fish averaging(250.83±2.12) g were reared in indoor aquarium tank(3.0 m×0.8 m×0.8 m),and fecal samples were collected by abdominal pressure method after one week.The results showed that apparent digestibility for dry matter,protein,crude fat,amino acids,phosphorus and energy of nine feed ingredients were 68.07%-92.69%,81.54%-92.75%,84.82%-103.44%,63.07%-95.56%,41.48%-97.55% and 68.91%-97.81%,respectively.Corn gluten meal showed the best apparent digestibility for all nutritions.Silkworm pupa had the highest apparent digestibility of four animal protein feedstuffs,and the next was blood meal.Apparent digestibility of enzyme feather meal was better than expanded feather meal in addition to crude fat.Barley grain had the highest protein and amino acid digestibility,but the apparent digestibility for dry matter,crude fat and energy were significantly lower than that of corn and broken rice.In conclusion,corn gluten meal and silkworm pupa can be used as high quality plant protein and animal protein sources,respectively.Blood meal,and feather meal can be used as a small amount with other feedstuffs.Corn and broken rice can be used as the main energy feed ingredients because of the higher energy values,and barley grain also can be used suitably for bluntnose black bream because of the balance of amino acids.