Department of Food, Agriculture and BioResources, Asian Institute of Technology, Klong Luang 12120, Thailand.
Feed Technology Department, Charoen Pokphand Group, Bangrak, Bangkok 10500, Thailand.
Poult Sci. 2019 Oct 1;98(10):4685-4693. doi: 10.3382/ps/pez171.
Effects of dietary non-phytate phosphorus (nPP) restriction on growth and duodenal type IIb sodium-dependent phosphate cotransporter (NaPi-IIb) genes were observed. A total of 432 one-day old Cobb500 male broiler chickens in 36 cage pens were divided into 6 groups with each group containing 6 pens. Each group was treated with one of the diets containing 0.33, 0.37, 0.41, 0.45, 0.49, and 0.53% of nPP up to 14 D. During 15 to 31 D, birds were treated with one of the diets containing 0.23, 0.27, 0.31, 0.35, 0.39, and 0.43% of nPP. Level of Ca was kept the same across all treatments. Dietary nPP level influenced (P < 0.001) weight gain and feed intake in both growth phases, whereas effect on feed per gain ratio was seen only in the second phase. Toe ash, tibia ash, and tibia breaking strength responded to treatments (P < 0.01) at 14 D. Only tibia ash content was significantly improved (P < 0.001) at 31 D. Growth and bone parameters linearly improved with an increase in dietary nPP content (P < 0.05). Above dietary nPP 0.41% and 0.31% for first phase and second phase, respectively, no significant improvement was seen. Duodenal NaPi-IIb mRNA overexpressed with a decrease in dietary nPP in both phases (P < 0.05). Relative expression of NaPi-IIb in lowest nPP group were 2.2 folds higher in the first phase and 3.6 folds higher in the second phase compared to respective highest nPP groups of each phase. No significant change in NaPi-IIb expression was seen above 0.37% of dietary nPP for 14 D and 0.31% of dietary nPP for 31 D. Dietary requirements of nPP 0.41% for 0 to 14 D and 0.31% for 15 to 31 D were adequate for optimal growth and bone parameters. This study fills the gap in understanding of intestinal NaPi-IIb expression in response to dietary nPP restriction in broilers older than 21 D of age.
研究了日粮非植酸磷（nPP）限制对生长和十二指肠 IIb 型钠依赖性磷酸盐共转运体（NaPi-IIb）基因的影响。将 432 只 1 日龄的科宝 500 雄性肉鸡分为 36 个笼养组，每组 6 个笼。每组用含 0.33%、0.37%、0.41%、0.45%、0.49%和 0.53%nPP 的日粮处理，直到 14 天。在 15 至 31 天期间，用含 0.23%、0.27%、0.31%、0.35%、0.39%和 0.43%nPP 的日粮处理。所有处理的钙水平保持不变。日粮 nPP 水平影响（P < 0.001）两个生长阶段的体重增加和饲料摄入量，而对饲料增重比的影响仅见于第二阶段。14 天时，脚趾灰分、胫骨灰分和胫骨强度对处理有反应（P < 0.01）。只有胫骨灰分含量在 31 天时显著提高（P < 0.001）。随着日粮 nPP 含量的增加，生长和骨骼参数呈线性提高（P < 0.05）。在第一阶段和第二阶段分别为日粮 nPP 0.41%和 0.31%以上，没有显著改善。在两个阶段，随着日粮 nPP 的减少，十二指肠 NaPi-IIb mRNA 过度表达（P < 0.05）。在第一阶段，最低 nPP 组的 NaPi-IIb 相对表达量比各自的最高 nPP 组高 2.2 倍，在第二阶段高 3.6 倍。在 14 天用 0.37%以上的日粮 nPP 和 31 天用 0.31%以上的日粮 nPP 时，NaPi-IIb 表达没有显著变化。0 至 14 天的日粮 nPP 需要量为 0.41%，15 至 31 天的日粮 nPP 需要量为 0.31%，足以满足最佳生长和骨骼参数的需要。本研究填补了对 21 日龄以上肉鸡肠道 NaPi-IIb 表达对日粮 nPP 限制反应的理解空白。
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