无鱼粉低磷饲料中添加中性蛋白酶和植酸酶对建鲤生长及营养物质利用的影响

在无鱼粉低磷饲料中添加中性蛋白酶、中性植酸酶, 考察对建鲤(Cyprinus carpio var. Jian)生长、营养物质消化率和沉积率、血浆生化指标及肠道组织学的影响。配制含鱼粉5%和磷酸二氢钙1.5%的正对照饲料、无鱼粉饲料、无鱼粉低磷饲料(磷酸二氢钙1.0%)和在无鱼粉饲料中添加175 mg/kg蛋白酶, 在无鱼粉低磷饲料中添加175 mg/kg蛋白酶+300 mg/kg植酸酶的5组等蛋白饲料, 饲喂初始体重为(52.5±2.0) g的建鲤10周。结果表明: 对照组具有最高增重率和最低饲料系数(P<0.05), 无鱼粉饲料和无鱼粉低磷饲料组的增重率、蛋白质和磷沉积率、蛋白质和钙消化率均显著下降(P<0.05); 在无鱼粉饲料中添加蛋白酶后, 提高了建鲤增重率13.1%(P<0.05), 达到和对照组基本一致的水平; 显著提高了蛋白质、钙消化率和肠绒毛高度, 降低了饲料系数(P<0.05); 在无鱼粉低磷饲料中添加蛋白酶和植酸酶后, 显著提高了脂肪、蛋白质、磷沉积率和蛋白质、钙、磷消化率(P<0.05), 增加了前肠绒毛长度和隐窝深度(P<0.05), 提高了血浆磷浓度(P<0.05)。以上结果表明, 在全植物性蛋白饲料中添加蛋白酶, 在全植物蛋白的低磷饲料中同时添加蛋白酶和植酸酶可以促进建鲤生长, 提高对营养物质的消化率和沉积率, 促进肠道生长发育。

EFFECTS OF SUPPLEMENTATION OF NEUTRAL PROTEASE AND NEUTRAL PHYTASE IN FISH MEAL FREE DIET WITH LOW PHOSPHORUS LEVEL ON GROWTH,NUTRIENTS DIGESTIBILITY AND DEPOSITION OF JIAN CARP (CYPRINUS CARPIO VAR. JIAN)

To evaluate the effects of the supplementation of neutral protease and neutral phytase in fish meal free diet with low phosphorus level on the growth, nutrients digestibility, nutrients deposition, serum biochemical index, and intestinal morphology of Jian carp (Cyprinus carpio var. Jian), five diets were prepared as the positive control diet [5% fish meal, 1.5% Ca(H₂PO₄)₂], fish meal free diet (FMF) supplemented without or with 175 mg/kg protease, low phosphorus and fish meal free diet [1.0% Ca(H₂PO₄)₂, LP-FMF] supplemented without or with 175 mg/kg protease+300 mg /kg phytase (LP-FMF+Pr+Ph), respectively, for a 10-weeks trial. The results indicated that the control group had the highest weight gain rate (WGR) and the lowest feed conversion ratio (FCR) among all groups (P<0.05). TheWGR, the retention ratios of protein and P, the digestibilities of protein and calcium of FMF group and LP-FMF group were significantly lower than those of control group (P<0.05). The supplementation of protease (FMF+protease) improved theWGR by 13.1% (P<0.05), and promoted the digestibilities of protein and calcium, and improved the foregut villus length, and decreased theFCR (P<0.05) compared with FMF group. The LP-FMF+Pr+Ph group showed the higher retention ratios of lipid, protein and phosphorus (P<0.05), the higher digestibilities of protein, phosphorus and calcium (P<0.05), the longer villus length and crypt depth, and the higher serum phosphorus level (P<0.05) than the LP-FMF group. These results indicated that the supplementation of protease in fish meal free diet and the supplementation of protease and phytase in low phosphorus and fish meal free diet could improve the growth performance, the digestibility and retention ratios of nutrients, and promote the intestinal development of Jian carp.