HuPro蛋白酶在不同蛋白水平罗非鱼饲料中的应用效果研究

Studies on the application of HuPro protease in different dietary protein contents of GIFT tilapia

为了探讨Hu Pro蛋白酶在不同蛋白水平吉富罗非鱼饲料中的应用效果,将375尾平均体重为(11.90±1.32)g的吉富罗非鱼随机分成5组:高蛋白组(对照组)、中蛋白组(Ⅰ组)、中蛋白+蛋白酶组(Ⅱ组)、低蛋白组(Ⅲ组)、低蛋白+蛋白酶组(Ⅳ组),每组3个平行,每个平行25尾鱼,饲养65 d后测定生长、饲料系数、蛋白质表观消化率、消化酶酶活等指标。结果表明,在中蛋白组中添加Hu Pro蛋白酶,吉富罗非鱼的增重率、特定生长率、蛋白质效率和蛋白质表观消化率较31%蛋白的对照组提高了0.48%、0.44%、8.71%和5.39%,饲料系数降低了0.68%,均与对照组无显著性差异;与对照组相比饲料成本下降了4.99%,存在显著性差异。在低蛋白组中添加Hu Pro蛋白酶,吉富罗非鱼的增重率、特定生长率、蛋白质效率较31%蛋白的对照组降低了18.18%、10.04%、7.47%,蛋白质表观消化率、饲料系数、饲料成本较对照组提高了8.66%、25.34%、6.59%,除增重率与对照组存在显著性差异外,其它各指标与对照组差异不显著。这表明在31%蛋白水平的基础上,降低2%的蛋白水平添加Hu Pro蛋白酶,不会对吉富罗非鱼的生长性能和对饲料的利用造成影响,但降低4%的蛋白水平添加Hu Pro蛋白酶会影响到吉富罗非鱼的生长性能和对饲料的利用。消化酶的测定结果表明,在不同蛋白水平饲料中添加Hu Pro蛋白酶(Ⅱ组、Ⅳ组),与未添加Hu Pro蛋白酶组(Ⅰ组、Ⅲ组)相比,吉富罗非鱼肝、胃、肠的蛋白酶活性与胃、肠的淀粉酶和脂肪酶活性有所提高,而肝淀粉酶和肝脂肪酶活性无明显的变化(P>0.05)。

The present study was conducted to determine the effect of Hu Pro protease in the diet withdifferent protein contents to GIFT tilapia. Experimental diets were divided into 5 groups: High proteingroup(Control group), medium protein group(Group,Ⅰ), medium protein and protease group( Group,Ⅱ), low protein group(Group Ⅲ), low protein and protease group(Group,Ⅳ), respectively, and fed tothree replicate groups of 25 tilapia [mean initial weight = 11.90±1.32 g; mean ± SD)] for 9 weeks. Re-sults showed that the medium protein group supplemented with protease had a higher weight gain rate,specific growth rate, protein efficiency and apparent protein digestibility than the medium proteingroup. Compared with the control group, the medium protein group supplemented with protease had alower feed cost and feed conversion ratio. Also, this phenomenon was not consistent with the low pro-tein group. This showed that based on the dietary 31% protein content, 2% lower dietary protein con-tent in diet supplemented with Hu Pro proteasedietary was feasible, and the growth performanceand feed utilization of GIFT tilapia was not af-fected. But, the growth performance and feed uti-lization of GIFT tilapia was affected, in the diet decreased in 4% protein content. The digestive enzyme results showed that in the diet supplementedwith protease of different dietary protein contents, the protease activity increased in the liver, stomachand intestine, and amylase and lipase activity in stomach and intestine, and had no significant influ-ence on liver amylase and lipase activity.