| In ruminants, dietary protein is extensively degraded by the rumen microbes into ammonia. Microorganisms in the rumen use the ammonia as a nitrogen source to synthesise cell protein. It is microbial protein that is the major protein source to the animal. The biological efficiency in this conversion process profoundly affects the efficiency of feed utilization. It is important to determine how much protein has been produced. |
However, direct measurement of this contribution requires surgical intervention on the animal. A new method has been developed to estimate microbial protein supply based on analysis of purine metabolites in urine.It does not require surgery on the animals.
This method has now provided a simple tool to study factors affecting microbial protein production such as dietary nitrogen and energy sources, probiotics, defaunation, ruminal digesta passage rate and methods of forage preservation, and thus to explore ways of improving feed utilization.
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Estimation of microbial protein supply to sheep and cattle based on urinary excretion of purine derivatives - an overview of the technical details. By X B Chen and M J Gomes. [ 288 K] |
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Research on urinary excretion of purine derivatives in ruminants: past, present and future. By X B Chen and E R Orskov [ 323 K] |
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A training CD on the purine technique published by the Joint FAO/IAEA Division  More details.  Read online |
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Software utilities for purine work, developed by X B Chen [ Download 1829K] More details. |
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| Photo of participants of the 4th project meeting in Vietnam 2002 of a FAO/IAEA research project on development and application of the purine technique. Pictured here are some of the active authors on purine work: Dr X.B.Chen (front left), Prof. P.Susmel (rear left), Dr J.Balcells (rear left 6th), Dr E.R.Orskov (rear right 5th), Prof. J.Nolan (rear, right 3rd), Dr J.B.Liang (rear right). Also pictured here are previous and current technical officers,Dr N.Jayasuria (rear left 2rd) and Dr H.P.S.Makkar (rear left 3rd) from IAEA |
