低钙磷饲粮添加高剂量植酸酶对1～21日龄黄羽肉鸡生长性能、胫骨性能、血清生化指标的影响

Effects of High Dose Phytase on Growth Performance,Tibia Performance,Serum Biochemical Indexes in Yellow-Feathered Broilers Aged from 1 to 21 Days Fed Low Calcium and Phosphorus Diets

本试验旨在研究低钙磷饲粮中添加高剂量植酸酶对1～21日龄黄羽肉鸡生长性能、胫骨性能、血清生化指标和钙磷代谢关键基因表达量的影响。试验选用1 080只1日龄岭南黄羽肉公雏,根据体重一致原则,分为6个组(每组6个重复,每个重复30只肉鸡):对照(PC)组(正常的磷酸氢钙添加水平,非植酸磷水平达到标准要求)、中非植酸磷(MP)组(PC组降低50%磷酸氢钙添加水平,非植酸磷水平减少1/3)、MP+2 000组(MP组+2 000 FTU/kg植酸酶)、MP+4 000组(M P组+4 000 FTU/kg植酸酶)、低非植酸磷(LP)+2 000组[PC组不添加磷酸氢钙,非植酸磷水平减少2/3+2 000 FTU/kg植酸酶)、LP+4 000组(PC组不添加磷酸氢钙,非植酸磷水平减少2/3+4 000 FTU/kg植酸酶),各组饲粮钙磷比保持在1.4∶1.0左右。试验期21 d。结果表明:1)与PC组相比,MP+4 000、LP+4 000组肉鸡终末体重、平均日增重显著提高(P<0.05);各植酸酶添加组肉鸡平均日采食量显著提高(P<0.05)。与MP组相比,各植酸酶添加组肉鸡终末体重、平均日增重、平均日采食量均显著提高(P<0.05),料重比有降低的趋势(P=0.088)。2)与PC组相比,M P+4 000、LP+4 000组胫骨折断力显著提高(P<0.05); M P组胫骨脱水脱脂重、灰分和磷含量显著降低(P<0.05)。与MP组相比,各植酸酶添加组胫骨折断力显著提高(P<0.05); MP+4 000组胫骨脱水脱脂重显著提高(P<0.05); MP+4 000、LP+4 000组胫骨灰分、磷含量显著提高(P<0.05);植酸酶的添加有升高胫骨钙含量的趋势(P=0.055)。3)与PC组相比,MP组血清磷含量显著降低(P<0.05)。与MP组相比,MP+2000、MP+4 000、LP+4 000组血清磷含量显著升高(P<0.05);各植酸酶添加组血清钙含量有升高的趋势(P=0.054),血清碱性磷酸酶活性有降低的趋势(P=0.089)。4)与PC组相比,MP组肾脏克洛索蛋白、成纤维生长因子受体1(Fgfr1)基因表达量显著下调(P<0.05)。与MP组相比,MP+4 000组肾脏克洛索蛋白、Fgfr1基因表达量显著上调(P<0.05);添加植酸酶对肾脏1α-羟化酶基因表达量影响不显著(P>0.05)。综上,低钙磷饲粮添加高剂量植酸酶可提高1～21日龄黄羽肉鸡生长性能,促进矿物元素在胫骨的沉积,改善胫骨性能,调节血液和肾脏钙磷代谢,维持机体钙磷平衡。

The aim of this experiment was to study the effects of high dose phytase on growth performance,tibia performance,serum biochemical indexes and the key gene expression levels of calcium and phosphorus metabolism in yellow-feathered broilers aged from 1 to 21 days fed low calcium and phosphorus diets.One thousand and eighty 1-day-old Lingnan yellow-feathered male broilers were randomly assigned to six groups according to body weight(each group consisted of six replicates with 30 broilers) :control(PC) group [normal calcium hydrophosphate level and non-phytate phosphorus(NPP) level],medium NPP(MP) group(PC group reduced by 50% calcium hydrophosphate and 1/3 NPP),MP+2 000 group(2 000 FTU/kg phytase was added to MP group),MP+4 000 group(4 000 FTU/kg phytase was added to MP group),Low NPP(LP) +2 000 group(2 000 FTU/kg phytase was added to PC group without calcium hydrophosphate and NPP reduced by 2/3),LP+4 000 group(4 000 FTU/kg phytase was added to PC group without calcium hydrophosphate and NPP reduced by 2/3),and the ratio of calcium to phosphorus in diets remained at 1.4∶1.0 in each group.The experiment lasted for 21 days.The results showed as follows:1) compared with PC group,final body weight and average daily gain of broilers in MP + 4 000 and LP + 4 000 groups significantly increased(P <0.05);average daily feed intake of broilers phytase groups significantly increased(P<0.05).Compared with MP group,final body weight,average daily gain and average daily feed intake of broilers in phytase groups significantly increased(P<0.05),feed/gain had a decrease trend(P=0.088).2) Compared with PC group,tibia broking strength in MP+4 000 and LP+4 000 groups significantly increased(P<0.05);dehydrated and degreased weight and contents of ash and phosphorus of tibia in MP group significantly decreased(P<0.05).Compared with MP group,tibia broking strength in phytase groups significantly increased(P < 0.05);dehydrated and degreased weight of tibia in MP+4 000 group significantly increased(P<0.05);contents of ash and phosphorus of tibia significantly increased(P<0.05);tibia calcium content had a increase trend by adding phytase(P=0.055).3) Compared with PC group,serum phosphorus content in MP group significantly decreased(P<0.05).Compared with MP group,serum phosphorus content in MP + 2000,MP + 4 000,LP +4 000 groups significantly increased(P < 0.05);calcium serum calcium in phytase groups had an increase trend(P=0.054),serum alkaline phosphatase activity had a decrease trend(P=0.089).4) Compared with PC group,gene expression levels of klotho and fibroblast growth factor receptor 1(Fgfr1) of the kidney in MP group significantly increased(P<0.05).Compared with MP group,gene expression levels of klotho and Fgfr1 of the kidney in MP + 4 000 group significantly increased(P < 0.05);gene expression level of 1α-hydroxylase of kidney did not affected by adding phytase(P>0.05).In conclusion,adding high dose phytase to low calcium and phosphorus diets can improve the growth performance of yellow-feathered broilers aged from 1 to 21 days,promote deposition of mineral element in tibia and improve tibia performance,regulate metabolism of calcium and phosphorus in serum and kidney and maintain the balance of calcium and phosphorus.