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首页> 外文学位 >Influence of phytate and phytase on the digestion and uptake of nutrients in the chicken (Gallus domesticus) and the white pekin duck (Anas platyrinchos domesticus).
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Influence of phytate and phytase on the digestion and uptake of nutrients in the chicken (Gallus domesticus) and the white pekin duck (Anas platyrinchos domesticus).

机译：肌醇六磷酸和肌醇六磷酸酶对鸡（Gallus domesticus）和白北京鸭（Anas platyrinchos domesticus）的养分消化和吸收的影响。

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摘要

Phytates have anti-nutritional effects but the mechanisms of most of them are poorly understood. In the first study, the effect of different forms of phytates on endogenous losses in chicken and duck were investigated. The form of phytate affected the extent and nature of endogenous losses. The second study examined the effect of phytate on the uptake of amino acids or glucose from the jejunum in chicken. Presence of phytate decreased the absorption of some specific free amino acids and not others. The third and fourth studies compared efficacies of various phytase sources in overcoming anti-nutritional effects of phytates in broiler chicks. Three phytase sources derived from Escherichia coli and expressed in three different yeast systems were equally efficacious in improving growth and nutrient utilization. Also efficacy of Escherichia coli phytase was compared with that of Peniophora lycii phytase. The Escherichia coli phytase was more efficacious in improving growth and mineral utilization whereas Peniophora lycii phytase was more efficacious in improving ileal digestibility of amino acids. The fifth study compared the two phytase sources for their resistance to hydrolysis in the digestive tract. The Escherichia coli phytase was more resistant than the Peniophora lycii phytase. The sixth and seventh studies investigated the role of dietary composition in the regulation of intestinal phytase. When cholecalciferol concentration in diet was increased there was decreased Km of intestinal phytase in ducklings, but increased Vmax and Km of the enzyme in broiler chicks. When phosphorus concentration in diet was increased there was no change in intestinal phytase activity in ducklings but a decreased Vmax and Km of the enzyme in broiler chicks. In the seventh study, addition of phytate to a chemically defined casein diet reduced the Vmax of the intestinal phytase but the Km of the enzyme was not affected. Hence, intestinal phytase may be regulated by manipulating diet composition.
机译：植酸盐具有抗营养作用，但大多数机制尚不清楚。在第一项研究中，研究了不同形式的肌醇六磷酸对鸡鸭的内源性损失的影响。肌醇六磷酸的形式影响内源性损失的程度和性质。第二项研究检查了肌醇六磷酸对鸡空肠中氨基酸或葡萄糖摄取的影响。肌醇六磷酸的存在会降低某些特定游离氨基酸的吸收，而不会降低其他吸收。第三和第四项研究比较了各种肌醇六磷酸酶来源在克服肉鸡肌醇六磷酸酯抗营养作用方面的功效。来自大肠杆菌并在三种不同酵母系统中表达的三种肌醇六磷酸酶在提高生长和营养利用方面同样有效。还比较了大肠杆菌肌醇六磷酸肌醇六磷酸酶的功效。大肠杆菌肌醇六磷酸肌醇六磷酸酶在提高生长和矿物质利用方面更有效，而对虾青霉菌肌醇六磷酸酶在提高氨基酸的回肠消化率方面更有效。第五项研究比较了两种植酸酶对消化道中水解的抵抗力。大肠埃希氏菌植酸酶比李氏青霉菌植酸酶更具抗性。第六和第七项研究调查了饮食组成在肠道植酸酶调节中的作用。当日粮中胆钙化固醇浓度增加时，雏鸭肠道肌醇六磷酸酶的Km降低，而肉仔鸡的Vmax和酶的Km升高。当日粮中的磷浓度增加时，小鸭的肠肌醇六磷酸酶活性没有变化，而肉仔鸡的Vmax和Km降低。在第七项研究中，在化学定义的酪蛋白饮食中添加植酸盐可降低肠道植酸酶的Vmax，但不会影响该酶的Km。因此，可以通过控制饮食组成来调节肠道植酸酶。

著录项

  • 作者

    Onyango, Edward Michieka.;

  • 作者单位

    Purdue University.;

  • 授予单位 Purdue University.;
  • 学科 Biology Animal Physiology.; Agriculture Animal Culture and Nutrition.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 221 p.
  • 总页数 221
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生理学;饲料;
  • 关键词

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