Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany.
Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
Poult Sci. 2019 Nov 1;98(11):5562-5570. doi: 10.3382/ps/pez309.
Gnotobiotic broiler chickens were used to study interactive effects of supplemented phosphorus, calcium (PCa), and phytase (Phy) on myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) degradation and release of myo-inositol in the digestive tract. In 2 subsequent runs, the chickens were subjected to 1 of 4 dietary treatments with and without PCa and Phy supplementation. Sanitized eggs were hatched in 8 germfree isolators, and a minimum of 9 male Ross 308 chickens were placed in each pen (total 16 pens). Treatments implemented on day 10 included gamma-irradiated diets without (PCa-; 4.1 g P and 6.2 g Ca/kg DM) or with (PCa+; 6.9 g P and 10.4 g Ca/kg DM) monosodium phosphate and limestone supplementation and without (Phy-) or with (Phy+) 1,500 FTU Phy/kg feed in a factorial arrangement. On day 15, digesta was collected from different sections of the intestinal tract and analyzed for InsP isomers and myo-inositol. The isolators did not remain germfree, but analysis of contaminants and results of InsP degradation indicated no or minor effects of the identified contaminants. Prececal InsP6 disappearance was 42% with the PCa-Phy- treatment and 17% with PCa+Phy-. No InsP3-4 isomers were found in the digesta of the terminal ileum in PCa-Phy-. The concentration of myo-inositol in the ileal digesta from PCa-Phy- (6.1 μmol/g DM) was significantly higher than that from PCa+Phy- (1.7 μmol/g DM), suggesting rapid degradation of the lower InsP isomers by mucosal phosphatases and their inhibition by PCa. Phytase supplementation increased InsP6 disappearance and prevented inhibitory effects of PCa supplements (72% in PCa-Phy+ and 67% in PCa+Phy+). However, PCa supplementation reduced the degradation of lower InsP isomers mainly in the posterior intestinal sections in the presence of Phy, resulting in significantly lower myo-inositol concentrations. It is concluded that mucosa-derived phosphatases might significantly contribute to InsP6 degradation in broiler chickens. The potential of mucosa-derived phosphatases to degrade InsP6 and lower InsP is markedly reduced by dietary PCa supplementation.
无菌肉鸡用于研究补充磷、钙（PCa）和植酸酶（Phy）对肌醇 1,2,3,4,5,6-六磷酸（InsP6）降解和肌醇在消化道中释放的相互作用的影响。在随后的 2 次运行中，鸡接受了 4 种饮食处理中的 1 种，有无 PCa 和 Phy 补充。无菌蛋在 8 个无菌隔离器中孵化，每个围栏（共 16 个围栏）至少放置 9 只雄性罗斯 308 只鸡。第 10 天实施的处理措施包括未辐照的饮食（PCa-；4.1 g P 和 6.2 g Ca/kg DM）或添加单磷酸二氢钠和石灰石补充剂的饮食（PCa+；6.9 g P 和 10.4 g Ca/kg DM），以及有无 1500 FTU Phy/kg 饲料的 Phy-（Phy-）或 Phy+（Phy+）的因素安排。第 15 天，从肠道不同部位收集食糜并分析 InsP 异构体和肌醇。隔离器未保持无菌，但污染物分析和 InsP 降解结果表明，鉴定出的污染物没有或只有轻微影响。PCa-Phy-处理时前肠 InsP6 消失率为 42%，PCa+Phy-处理时为 17%。在 PCa-Phy-的回肠内容物中未发现 InsP3-4 异构体。PCa-Phy-（6.1 μmol/g DM）的回肠食糜中肌醇浓度明显高于 PCa+Phy-（1.7 μmol/g DM），提示粘膜磷酸酶迅速降解较低的 InsP 异构体，并被 PCa 抑制。植酸酶补充增加了 InsP6 的消失，并防止了 PCa 补充剂的抑制作用（PCa-Phy+中为 72%，PCa+Phy+中为 67%）。然而，PCa 补充剂减少了低 InsP 异构体在后肠段的降解，主要是在有 Phy 的情况下，导致肌醇浓度明显降低。结论：粘膜来源的磷酸酶可能对肉鸡 InsP6 降解有重要贡献。日粮 PCa 补充显著降低了粘膜来源的磷酸酶降解 InsP6 和较低 InsP 异构体的能力。
