ACTA VETERINARIA ET ZOOTECHNICA SINICA

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Study on Microbial N Yield Measured with 15N and Purine Bases in Mutton Sheep

MA Tao1, DIAO Qi-yu1*, DENG Kai-dong2, JIANG Cheng-gang1, TU Yan1, ZHANG Nai-feng1, WANG Yong-chao1, LIU Jie1, ZHAO Yi-guang1   

  1. (1. Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; 2. College of Animal Science and Technology, Jinling Institute of Technology, Nanjing 210038, China)
  • Received:2012-02-05 Online:2012-12-26 Published:2012-12-26

Abstract:

Two different microbial markers, 15N and purine bases(PB), were used in this experiment with the purpose to establish the relationship between the two methods and provide a precise way for measuring microbial N yield in mutton sheep. Twelve Dorper ( Small-tailed Han crossbreds, noncastrated male lambs ((41.3±2.8) kg BW) were randomly assigned to three levels of dry matter intake: ad libitum intake, 70% or 40% of the ad libitum intake, with four lambs at each level. The experiment lasted for 25 d (10 d for adaptation and 15 d for trial period). The ruminal bacterial components (N, purine bases and purine bases/N) were not affected by dietary treatment (P>0.05). Duodenal flows of dry matter, organic matter, non-ammonia nitrogen and PB decreased significantly with decrease of feed intake (P<0.05). Microbial N yield measured with either 15N or PB decreased significantly with decrease of feed intake (P<0.05) whereas the efficiency of microbial synthesis was not affected by dietary treatment for both markers (P>0.05). The result indicate that microbial N measured with 15N showed a smaller within-treatment variation than that measured with PB, and thus 15N can be a reliable marker for accurately quantifying microbial N.

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