Department of Animal Sciences, Purdue University, West Lafayette, IN 47906, USA.
Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany.
Poult Sci. 2020 Feb;99(2):981-991. doi: 10.1016/j.psj.2019.10.016. Epub 2019 Dec 26.
This study was conducted to determine effects of high phytase use on growth performance, amino acid (AA) digestibility, intestinal phytate breakdown, and nutrient transporter expression in starter broiler chickens. Male Ross 308 chicks were allocated to 24 pens, at 15 birds/pen and assigned to one of 4 dietary treatments. Treatments were: a control diet (PCa+) that contained adequate levels of calcium (Ca) and phosphorus (P) for growing broiler chicks; a reduced Ca and P diet (PCa-:-1.5 g P/kg and -1.6 g Ca/kg), and 2 additional diets in which phytase was supplemented in the PCa- diet at 1,500 (PCa-Phy1500) and 3,000 (PCa-Phy3000) FTU/kg feed. A common starter diet was fed from day 1 to 8. From day 8 to 22, birds were fed the 4 experimental diets. On day 22, birds were killed for sample collection. From day 8 to 15, average daily gain and average daily feed intake were not different across treatments (P < 0.05) but gain-to-feed ratio (G:F) was reduced (P < 0.006) in the PCa- treatment compared with other treatments. There were no further performance differences, but a tendency of phytase treatments improving the overall G:F (P = 0.079; day 8-22). Up to both the duodenum-jejunum and ileum, phytate, P, and Ca disappearance were increased (P < 0.05) in the PCa-Phy1500 and PCa-Phy3000 treatments compared with PCa- treatment. Phytase dose dependently increased myoinositol (MI) concentration in the digesta from both the duodenum-jejunum and ileum (P < 0.001). The highest concentration of MI was found in the PCa-Phy3000 treatment. Plasma MI concentration was increased by phytase supplementation (P < 0.001). Prececal disappearance of Cys was lower (P < 0.05) in the PCa- treatment than in PCa1and PCa-Phy3000 treatment. Expression of MUC2 in the duodenum-jejunum was higher (P < 0.05) in the PCa-Phy3000 treatment than in other treatments. Phytase-induced hydrolysis of phytate led to elevated digesta and plasma MI concentrations and reduced digesta concentrations of phytate breakdown intermediates.
本研究旨在确定高植酸酶用量对生长性能、氨基酸（AA）消化率、肠道植酸盐分解以及生长前期肉鸡营养转运蛋白表达的影响。雄性罗斯 308 雏鸡被分配到 24 个笼中，每个笼 15 只，分为 4 种饮食处理。处理方法如下：对照组（PCa+），饲料中钙（Ca）和磷（P）含量足以满足生长前期肉鸡的需要；低 Ca 和 P 组（PCa-：-1.5 g P/kg 和 -1.6 g Ca/kg），在低 Ca 和 P 组的饲料中添加 1500（PCa-Phy1500）和 3000（PCa-Phy3000）FTU/kg 植酸酶的两种额外饲料。从第 1 天到第 8 天，雏鸡喂食普通基础饲料。从第 8 天到第 22 天，雏鸡喂食 4 种实验饲料。第 22 天，处死雏鸡收集样本。第 8 天至 15 天，各处理组的平均日增重和平均日采食量无差异（P < 0.05），但低 Ca 和 P 组的增重与采食量之比（G:F）低于其他处理组（P < 0.006）。进一步的性能差异，但植酸酶处理有提高整体 G:F 的趋势（P = 0.079；第 8-22 天）。在十二指肠-空肠和回肠中，与低 Ca 和 P 组相比，PCa-Phy1500 和 PCa-Phy3000 处理组的植酸盐、P 和 Ca 的消失量增加（P < 0.05）。植酸酶剂量依赖性地增加了十二指肠-空肠和回肠消化物中的肌醇（MI）浓度（P < 0.001）。在 PCa-Phy3000 处理组中发现了最高的 MI 浓度。血浆 MI 浓度因植酸酶的添加而增加（P < 0.001）。在低 Ca 和 P 组中，回肠前 Cys 的消失率低于 PCa1 和 PCa-Phy3000 处理组（P < 0.05）。十二指肠-空肠中 MUC2 的表达在 PCa-Phy3000 处理组中高于其他处理组（P < 0.05）。植酸酶诱导的植酸盐水解导致消化物和血浆 MI 浓度升高，植酸盐分解中间产物的消化物浓度降低。
