【作者】 王庆云；

【导师】 杨维仁；

【作者基本信息】 山东农业大学 ， 动物营养与饲料科学， 2008， 硕士

【摘要】 研究不同无机磷水平日粮中添加植酸酶对肉鸡生长性能、骨骼发育、血清生化指标、屠宰性能及养分利用率的影响,探讨日粮添加植酸酶条件下肉鸡的磷营养。选取1日龄肉鸡1 500只,随机分为5个处理,以磷酸氢钙为磷源作为对照组,其余4组磷酸氢钙水平分别为对照组的75%、50%、25%、0%,并添加植酸酶,各组钙磷比值为1.2～1.4。研究结果表明:本试验条件下,50%磷酸氢钙组日增重最高63.7g·d-1,料重比最低为1.81。无磷酸氢钙组日平均采食量111.4g·d-1、日增重56.7g·d-1显著低于对照组(P < 0.05)。肉鸡胫骨鲜重、脱脂率各处理间差异不显著(P >0.05),脱脂率随日粮中无机磷水平降低而升高;胫骨脱脂重随日粮中无机磷水平下降而降低,28日龄无磷酸氢钙组肉鸡胫骨脱脂重显著低于其他组(P <0.05)。28日龄肉鸡胫骨灰分含量无磷酸氢钙组显著低于其他各组(P <0.05);胫骨钙、磷含量无磷酸氢钙组低于其他各组,但各组之间差异不显著(P >0.05);28日龄肉鸡胫骨镁、锰、铜、铁、锌含量随日粮中无机磷水平降低逐渐升高,42日龄添加植酸酶组的肉鸡胫骨镁、锰、铁含量也有同样变化。肉鸡胫骨折断强度无磷酸氢钙组低于其他各组,其中28日龄该组肉鸡胫骨折断强度显著低于其他组(P <0.05)。血清钙、血清无机磷含量各处理间差异不显著(P >0.05);血清碱性磷酸酶活性以无磷酸氢钙组活性最高2 667.80 U·L-1。血清铜、锌含量各处理间差异不显著(P >0.05)。28日龄无磷酸氢钙组屠宰率、全净膛率、半净膛率显著低于对照组(P <0.05),胸肌率、腿肌率各处理间差异不显著(P >0.05);42日龄各处理间屠宰率、全净膛率、半净膛率、胸肌率、腿肌率差异不显著(P >0.05)。添加植酸酶的各处理净蛋白利用率均高于对照组,随无机磷水平降低分别比对照组高出2.10%,4.95%,3.48%,5.66%,但处理间差异不显著(P >0.05)。矿物质元素利用率随无机磷含量减少呈升高趋势。植酸酶添加组随无机磷水平降低分别比对照组排泄物中磷含量依次降低了11.0%、17.9%、23.9%、28.4%,无磷酸氢钙组与对照组差异显著(P <0.05)。日粮中添加植酸酶能提高肉鸡生长性能及矿物质元素的利用率,减少粪中磷排泄量。用血清碱性磷酸酶活性判断肉鸡钙、磷营养比用血清钙、血清无机磷更为敏感。降低日粮无机磷水平添加植酸酶,对肉鸡屠宰性能没有影响。日粮中添加植酸酶不能完全替代磷酸氢钙,以对照组磷酸氢钙水平的50%处理组(0～4周:Ca 0.76%,TP 0.54%;5～7周:Ca 0.70%,TP 0.53%)效果较好。鉴于植酸酶对矿物质元素的释放作用,有必要重新评估日粮配方中矿物质元素的需要量。更多还原

【Abstract】 An experiment was conducted to study phosphorus nutrition and effects of phytase supplementation in broilers fed different dietary levels of inorganic phosphorus on growth performance, bone growth, serum biochemical indicator, slaughter performance and nutrient utilization rate. A total of 1500 broilers were chosen and assigned randomly to five treatments. A diet of adequate inorganic phosphorus without phytase was used as control, and the other four calcium phosphate dibasic levels which were 75%, 50%, 25%, 0% of the control were performed with phytase addition, respectively. Dietary Ca: TP ratios between 1.2 to 1.4 were controlled in all treatments.The results demonstrated that ADG (63.7 g/d) of 50% calcium phosphate dibasic group was the highest and feed gain ratio (1.81) was the lowest in all groups. The results demonstrated that ADFI and ADG of no inorganic P group were 111.4 g/d and 56.7 g/d, which were significantly lower than the control (P <0.05) in the present experimental condition.Tibia fresh weight and fat-free rate were not significantly different in all treatments (P >0.05), and fat-free rate was increased in response to decreasing inorganic P levels; Tibia fat-free weight was decreased in response to decreasing inorganic P, and it was significantly lower than the other groups at 28d of the age (P <0.05). Tibia ash content in no inorganic P group was lower than the other groups at 28d of the age (P <0.05). Tibia Ca and P contents in no inorganic P group were lower than the other groups, but they did not differ significantly (P >0.05) among all treatments. Tibia Mg, Mn, Cu, Fe and Zn contents increased in response to decreasing dietary inorganic P at 28d of the age, Tibia Mg, Mn, Fe contents with phytase addition groups had the same variation at 42d of the age. Tibia breaking strength in no inorganic P group was lower than the other groups, and it was significantly lower than the other groups at 28d of the age (P <0.05).Serum inorganic P and calcium concentrations were not significantly different among treatments (P >0.05). Serum ALP activity of no inorganic P group was highest (2667.80 U/L) in all groups. Serum Cu and Zn contents were not significantly different among treatments (P >0.05).At 28d of the age, percentage of carcass yield, eviscerated yield and half-eviscerated yield of no inorganic P were significantly lower than the control (P <0.05), the breast and leg muscle percentage in all treatments were not significantly different (P >0.05). At 42d of age, the percentage of carcass yield, eviscerated yield, half-eviscerated yield, breast and leg muscle of all treatments were not significantly different (P >0.05).The NPU of all phytase addition groups were higher than the control group by 2.10%,4.95%,3.48%,5.66% with the decreasing inorganic P levels, but they were not significantly different among treatments (P >0.05). The treatment groups had the increasing tendency to the utilization rate of mineral elements in response to decreasing inorganic P levels. The phosphorus of phytase groups were lower than the control group by 11.0%, 17.9%, 23.9%, 28.4% with the deceasing inorganic P levels in excretion, and no inorganic P group was significantly different than the control group (P <0.05).The study indicated that the growth performance and utilization of the mineral elements were improved with phytase addition in diet, the fecal P excretion were reduced. The study indicated serum ALP activity was more sensitive in measurement dietary Ca and P nutrients than serum Ca and serum inorganic P. And the slaughter performance was not influenced with phytase addition in the decreasing dietary inorganic phosphorus levels. But phytase can not replace calcium phosphate dibasic completely. And 50% calcium phosphate dibasic group of the control (0-4W: Ca 0.76%, TP: 0.54%; 5-7W: Ca 0.70%, TP 0.53%) appeared to provide better efficacy. Respecting contribution of phytase on releasing binding minerals, it was necessary to reevaluate dietary requirements of mineral elements.更多还原