Nutrient Apparent Digestibility of Eight Feed Ingredients for Black Carp (Mylopharyngodon piceus Richardson)

The apparent digestibility of dry matter(DM),crude protein(CP),amino acids(AA),ether extract(EE),total phosphorus(TP) and gross energy(GE) of domestic fish meal,maggot meal,corn gluten meal,soybean meal,peanut meal,cottonseed meal,rapeseed meal and rice bran were determined for black carp(Mylopharyngodon piceus Richardson).The test diets consisted of 70% basal diet and 30% test feed ingredients,and added 0.1% Y2O3 as an indicator.Two hundred and seventy black carp with an average body weight of(60.17±1.28) g were randomly divided into 9 groups with 3 replicates in each group and 10 fish in each replicate.The fish in control group were fed a basal diet,and those in experiment groups were randomly fed one of 8 experimental diets.The fecal samples were collected by abdominal pressure method after one week.The results showed that apparent digestibility of DM,CP,EE,TP,GE and total AA of eight feed ingredients were 62.17% to 86.47%,83.34% to 95.84%,78.93% to 100.06%,37.33% to 81.99%,66.75% to 89.86% and 86.33% to 96.58%,respectively.In the eight feed ingredients,the highest apparent digestibility of DM,TP and GE was found in corn gluten meal,while soybean meal had the highest apparent digestibility of CP,EE and total AA.The lowest apparent digestibility of DM and GE was found in cottonseed meal,and rice bran had the lowest apparent digestibility of EE and TP.The apparent digestibility of CP was consistent with the apparent digestibility of total AA in the eight feed ingredients,and the lowest apparent digestibility of CP and total AA was found in maggot meal.In conclusion,soybean meal and corn gluten meal can be used as high-quality plant protein sources to serve as alternative fish meal in feed of black carp.The apparent digestibility of CP and AA is lower in maggot meal,so the amount of maggot meal in feed should not be too high.Peanut meal,cottonseed meal and rapeseed meal are also good plant protein sources in feed and conducive to the nutritional balance and reduce feed costs.Rice bran as an energy material of black carp must be kept fresh,and its dosage should be properly controlled in feed.