| Project/Area Number |
18580270
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Zootechnical science/Grassland science
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| Research Institution | Hiroshima University |
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Principal Investigator |
OBITSU Taketo Hiroshima University, Graduate School of Biosphere Science, Associate Professor (30194632)
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| Co-Investigator(Kenkyū-buntansha) |
SUGINO Toshihisa Hiroshima University, Graduate School of Biosphere Science, Assistant Professor (90363035)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,290,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Arginine / Urea / Amino acid metabolism / Stable isotopes / Calves / クレアチン / 一酸化窒素 |
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| Research Abstract |
It is important to rear healthy calves because consumers request safety agricultural products. Arginine, which is one of amino acids constituting body protein, has multiple functions in animal nutrition and health. Arginine is used as substrates not only for body protein synthesis but also for the production of nitrogen oxide that promotes immune response. Thus, quantification of arginine metabolism in calves is important to establish the management system for healthy growth of calves.
Urea production dramatically increases after weaning in calves, because of increased ammonia absorption from the rumen followed by increased dry matter intake and rumen development. Arginine is a substrate for urea production in the liver, so that increased urea production may facilitate the demands of plasma arginine for the urea synthesis. This additional demand of arginine would decrease its supply for body protein synthesis and other important functions. The objective of this study was to investigate the effect of weaning on anginine flux for urea production in young calves.
Holstein calves were fed only milk replacer till 4 weeks of age, then began to offer the concentrate diets and hay with milk replacer till 7 weeks. After weaning at 7 weeks, calves were fed only solid feeds. Calves were fed diets to satisfy the energy and protein requirements for growth rate of 0.7 kg/d. At 4 and 14 or 15 weeks, calves were infused with [guanido ^<15>N_2]arginine and [^<13>C]urea into the jugular vein to measure the flux of plasma arginine and the rate of conversion of guanido-N of plasma arginine to urea synthesized in the liver.
Urea production increased after weaning, but total plasma arginine flux decreased. The rate of plasma arginine converted to urea was not changed after weaning, but the proportion of plasma arginine used for urea production to total arginine flux was increased.
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