中文摘要：

分别在高鱼粉（12％，HFM）和低鱼粉（6％，LFM）饲料配方基础上，添加不同水平面包酵母提取物（Yeast Extract，YE），研究其对异育银鲫（Camssius auratus gibello）摄食率和摄食选择性的影响。每种基础饲料中分别添加0．5％和1．0％YE（HYE-0．5、HYE-1．0、LYE-0．5、LYE-1．0），此外各设一组添加0．05％甜菜碱作为正对照（HB和LB），共8组饲料，每组4种饲料中分别添加Y2O3、Yb2O3、La2O3、Nd2O3作为惰性标物，用于测定摄食选择性。依据不同基础饲料，试验分为2组，每组4个重复，每个重复30尾鱼，共进行2周短期有效性试验。第1周，每组分别饲喂不添加诱食剂的HFM和LFM饲料；第2周，各组分别将4种饲料等量混合过量饲喂，统计摄食量，并收集最后3d的粪便，检测粪便中4种稀土标物的含量。HFM组中，异育银鲫对添加0．05％甜菜碱饲料的偏好选择性与基础组差异不显著（P〉0．05），异育银鲫偏好选择添加酵母提取物的饲料，且随添加量的增加，选择性显著提高（P〈0．05）。LFM组中，异育银鲫显著倾向选择LYE-1．0组饲料（P〈0．05），LB组与LYE-0．5组差异不显著（P〉0．05）。

英文摘要：

The effects of yeast extract （YE） on feeding preference of Gibel carp （Carassius auratus gibeIio） in high fishmea] （12% fishmeal, HFM） and low fishmeal （6% fishmeal, LFM） basal diets were evaluated. In both basal diet, betaine and 0.5-1.0% of YE were tested and named as HB, HYE-0.5, HYE-1.0, LB, LYE-0.5 and LYE-1.0, respectively. Fish were equally divided into two groups, one fed the HFM diet, and the other fed the LFM diet during the first week, and in the second week, an equal mixture of each group of diets marked by Y2O3, Yb2O3, La2O3, Nd2O3were fed by apparent satiation twice per day. During the last 3 days of the 2nd week, faeces from each tank were collected. Preference for each diet was estimated based on the relative concentration of each marker in the faeces. As a result, in HFM basal diet group, Gibel carp much prefer to the diets HYEO.5 and HYE1.0, but in LFM group, fish showed higher preference to the LYE-1.0 diet, and there were no differences between LB and LYE-0.5 diet （P〉0.05）.