饲料中添加蛋白酶AG对鲤鱼鱼种生长和蛋白质消化酶活性的影响

通过2个试验研究了饲料中添加蛋白酶AG对鲤鱼生长和前肠蛋白质消化酶活性的影响.试验Ⅰ选用540尾均重11.7 g的鲤鱼,随机均分为6组,随机选取3组分别饲喂鱼粉含量为10%、15%、20%的3种等蛋白基础饲料,另外3组分别饲喂添加有175 mg/kg蛋白酶AG的以上3种饲料,试验期60 d.试验Ⅱ选取120尾均重48.7 g的鲤鱼,随机分为2组,一组饲喂鱼粉含量6%的基础饲料为对照组,另外一组饲喂添加175 mg/kg蛋白酶AG的基础饲料为试验组,试验期为30 d.试验Ⅰ结果表明:摄食10%鱼粉饲料和20%鱼粉 175 mg/kg蛋白酶AG饲料的鲤鱼分别具有最低和最高的增重率;在10%鱼粉饲料中添加蛋白酶AG显著提高了鱼体增重率(P<0.05),但在15%、20%鱼粉饲料中添加蛋白酶AG,对鱼体增重率没有显著影响.试验Ⅱ结果表明:相比于对照组,试验组鲤鱼增重率提高了6.4%(P<0.05),饲料系数降低了5.4%(P<0.05).试验Ⅰ和试验Ⅱ中,添加蛋白酶AG对鱼体肌肉水分、粗脂肪、粗蛋白质含量均无显著影响(P>0.05);对消化酶活性的测定表明,在鱼粉含量为10%、6%的基础饲料中添加蛋白酶AG,可显著提高前肠组织蛋白酶活性和食糜蛋白酶活性(P<0.05),但在鱼粉含量为15%、20%的基础饲料中添加蛋白酶AG,对前肠组织蛋白酶活性和食糜蛋白酶活性没有影响.综上所述,在鱼粉含量较低的饲料中添加蛋白酶AG,可提高鲤鱼消化道蛋白酶活性,改善生长性能.

Effects of Protease AG on Growth and Digestive Protease Activities of Common Carp (Cyprinus carpio L.) Fingerling

Two trials were conducted to investigate the effects of protease additive,Aquagrow(AG),on growth and digestive protease activities of common carp fingerling.In trial 1,six isonitrogenous basal diets with different fish meal(FM) contents(10%,15% and 20%) were prepared,including three with the supplementation of 175 mg/kg of protease AG and three without it.540 fish with an average body weight of 11.7 g were randomly divided into 6 groups,each of which was allotted to one of the six diets.The trial lasted for 60 days.In trial 2,120 fish with an average body weight of 48.7 g were randomly divided into two groups,in which one was fed with a low nitrogenous basal diet with 6% of FM,as the control group;the other was provided with the basal diet mentioned above,with the addition of 175 mg/kg of protease AG,as the experimental group.The trial period was 30 days.The results of trial 1 showed that fish fed with 10% FM diet had the lowest weight gain rate,while the group relied on(20% FM 175 mg/kg AG) diet had the highest weight gain rate.The weight gain rate of fish was significantly improved by adding 175 mg/kg AG in 10% FM group,but no significant effects if adding in 15% or 20% FM group.The results of trial 2 indicated that the weight gain rate was increased by 6.4%(P<0.05) and FCR decreased by 5.4%(P<0.05) with the addition of AG.There were no significant differences in the contents of muscle moisture,crude lipid and crude protein after addition of AG in both trials.The digestive protease activities of pre-intestine and chyme in(10% FM AG) and(6% FM AG) groups were significantly increased(P<0.05),compared with the two basal diet groups,but no significant difference was observed in 15% and 20% FM groups with the supplementation of AG.In conclusion,the growth performance and digestive protease activities of common carp fed with less fish meal could be improved by adding protease AG.