Nyannor E K D, Adeola O
Department of Animal Science, Purdue University, West Lafayette, IN 47907-2054, USA.
Poult Sci. 2008 Oct;87(10):2015-22. doi: 10.3382/ps.2007-00501.
The efficacy of corn expressing an Escherichia coli-derived gene (corn-based phytase; CBP) and an E. coli-derived microbial phytase (expressed in Pichia pastoris) sprayed onto a wheat carrier (Quantum) was comparatively evaluated in two 14-d broiler chicken studies. In experiment 1, a total of 288 seven-day-old male broiler chicks were grouped by weight into 8 blocks of 6 cages, with 6 birds per cage, and used to measure growth performance, bone mineralization, and nutrient utilization. In experiment 2, a total of 192 seven-day-old male broiler chicks were used, with 4 birds per cage. Six dietary treatment groups were randomly allotted to the cages within each of 8 blocks. The corn-soybean meal-based diets used in each study consisted of a positive control adequate in P and Ca; a negative control (NC) low in P and Ca (no added inorganic P); the NC supplemented with 3,630, 36,300, or 363,000 phytase units (FTU) of CBP/kg; and the NC + 3,630 FTU of Quantum/kg. Growth performance and bone mineralization criteria were reevaluated in the second broiler study. Data from the 2 experiments were combined because there was no diet x experiment interaction and analyzed as a randomized complete block design. Weight gain decreased (P < 0.05) with a reduction in dietary P and Ca in the NC diet. Weight gain, feed efficiency, and percentage of tibia ash of birds fed 3,630 FTU/kg of either CBP or Quantum phytase were not different. There was a quadratic response (P < 0.01) to CBP supplementation of the NC diets in weight gain of the broiler chicks. Feed intake increased quadratically (P < 0.01) with CBP supplementation of the NC diets, but CBP supplementation of the NC diets did not affect feed efficiency. Tibia ash of birds fed the positive control diet was greater (P < 0.01) than that of birds fed the NC diet. There was a quadratic response (P < 0.01) to CBP supplementation of the NC diets in tibia ash of the broiler chicks. Birds fed supplemental phytase had greater (P < 0.01) ileal and total tract P and Ca digestibility than birds fed the NC diet. Data from the study suggest that E. coli phytase expressed in corn is efficacious in P-deficient broiler chick diets for the improvement of growth performance and indices of P utilization, which would minimize the need for supplemental P in broiler diets.
在两项为期14天的肉鸡研究中，对表达大肠杆菌来源基因的玉米（玉米基植酸酶；CBP）和在毕赤酵母中表达的大肠杆菌来源的微生物植酸酶（喷洒在小麦载体Quantum上）的功效进行了比较评估。在实验1中，总共288只7日龄雄性肉鸡按体重分为8个区组，每个区组6个笼子，每个笼子6只鸡，用于测量生长性能、骨矿化和养分利用率。在实验2中，总共使用了192只7日龄雄性肉鸡，每个笼子4只鸡。将六个日粮处理组随机分配到8个区组中的每个笼子。每项研究中使用的基于玉米-豆粕的日粮包括磷和钙充足的阳性对照；磷和钙含量低的阴性对照（NC）（不添加无机磷）；添加3630、36300或363000单位植酸酶（FTU）/千克CBP的NC；以及添加3630 FTU/千克Quantum的NC。在第二项肉鸡研究中重新评估了生长性能和骨矿化标准。由于不存在日粮×实验交互作用，将两个实验的数据合并，并作为随机完全区组设计进行分析。NC日粮中磷和钙含量降低时，体重增加减少（P<0.05）。饲喂3630 FTU/千克CBP或Quantum植酸酶的鸡的体重增加、饲料效率和胫骨灰分百分比没有差异。在NC日粮中添加CBP，肉鸡体重增加呈二次反应（P<0.01）。在NC日粮中添加CBP，采食量呈二次增加（P<0.01），但在NC日粮中添加CBP不影响饲料效率。饲喂阳性对照日粮的鸡的胫骨灰分高于（P<0.01）饲喂NC日粮的鸡。在NC日粮中添加CBP，肉鸡胫骨灰分呈二次反应（P<0.01）。饲喂补充植酸酶的鸡的回肠和全肠道磷和钙消化率高于（P<0.01）饲喂NC日粮的鸡。该研究数据表明，玉米中表达的大肠杆菌植酸酶对缺乏磷的肉鸡日粮提高生长性能和磷利用指标有效，这将最大限度减少肉鸡日粮中补充磷的需求。
