Effect of dietary forage-to-concentrate ratios on urinary excretion of purine derivatives and microbial nitrogen yields in the rumen of Dorper crossbred sheep

Autor: Naifeng Zhang, C.-G. Jiang, K.-D. Deng, Y.-G. Zhao, Y. Tu, Qiyu Diao, T. Ma, J. Liu
Rok vydání: 2014
Předmět:
Zdroj: Livestock Science. 160:37-44
ISSN: 1871-1413
DOI: 10.1016/j.livsci.2013.11.013
Popis: This study investigated the effects of various dietary forage-to-concentrate ratios ( F : C ) on urinary excretion of purine derivatives (PD) and microbial nitrogen (MN) yields from the rumen of Dorper×thin-tailed Han crossbred sheep. Twelve Dorper×thin-tailed Han crossbred ram lambs (47.2±1.0 kg) fitted with ruminal and duodenal cannulae were randomly assigned to 12 levels of dietary F : C in an incomplete Latin-square experimental design (12 lambs×4 periods). Digestibility trials were conducted and MN was estimated using either 15 N or PD as markers. Urinary excretion of allantoin and total PD increased ( P F : C . Urinary excretion of uric acid or xanthine plus hypoxanthine was unaffected by F : C ( P >0.05). MN yields estimated using 15 N as a marker were greater than those predicted from urinary PD (12.5 vs. 11.5 g/d, P 15 N and urinary excretion of PD: MN (g/d)=–0.521+1.493×PD (mmol/d) ( r 2 =0.86, P 15 N or PD ( r 2 =0.60 and 0.77, respectively). Results suggest that urinary PD is an accurate indicator of MN from the rumen of Dorper crossbred sheep, and PNI reflected the conversion of nitrogen degradation to MN in the rumen.
Databáze: OpenAIRE
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