奥尼罗非鱼仔稚鱼饲料中适宜脂肪水平的研究

Study on the optimum dietary lipid level in tilapia larvae

为研究奥尼罗非鱼仔稚饲料中最适脂肪水平,采用脂肪水平分别为3%、5%、7%、9%、11%和13%的6种饲料投喂奥尼罗非鱼仔稚鱼28d。结果表明:(1)随着饲料脂肪含量从3%上升到11%,增重率先升高,在11%到达最高值,随后又逐渐下降,11%组显著高于其他各组,特定生长率、成活率的变化趋势与增重率相似,饲料脂肪水平不影响鱼的肥满度。饲料脂肪添加水平和增重率的二次回归分析表明,饲料脂肪含量在10.98%时,罗非鱼仔稚鱼有最大的增重效果。(2)鱼体水分、蛋白质和灰分含量随饲料脂肪水平的升高而显著下降(P<0.05),体脂肪随饲料脂肪含量的升高而升高(P<0.05)。(3)胃蛋白酶和淀粉酶活性随饲料脂肪含量升高而显著下降(P<0.05),脂肪酶活性则随饲料脂肪含量升高而不断升高。

A 28-day feeding trial with six dietary lipid levels （3 %, 5 %,7 %,9 %, 11% and 13 %）was conducted to investigate the optimum dietary lipid requirement for the growth,body composition and the digestive enzyme activity of tilapia larvae Oreochromis niloticusxO.aureus with initial weight（0.032±0.002） g.The results showed：（ 1 ）Weight gain rate was increased from 3 % to 11% and was maximized in the fish fed diets with 11% lipid level,then decreased in 13 % dietary lipid level.The variation trends of special growth rate, surivial rate were similar to the weight gain rate and condition factor was not affected by the level of dietary lipid.Quadratic regression analysis of weight gain rate against dietary lipid levels indicated that the optimal dietary lipid requirement for maximum weight gain of the tilapia Oreochromis niloticusxO.aureus was 10.98 %. （2）As the dietary lipid level increased,moisture,protein and ash of body were significantly decreased,while the lipid content of body was significantly increased （P 〈 0.05 ）. （3）As the dietary lipid level increased, the pepsin,and the amylase activity significantly decreased,while the lipase activity increased（P 〈 0.05）.