A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep
| dc.citation.doi | 10.2527/jas2014-8865 | |
| dc.citation.epage | 3017 | |
| dc.citation.issn | 0021-8812 | |
| dc.citation.issue | 6 | |
| dc.citation.jtitle | Journal of Animal Science | |
| dc.citation.spage | 3006 | |
| dc.citation.volume | 93 | |
| dc.contributor.author | Zhou, J. W. | |
| dc.contributor.author | Mi, J. D. | |
| dc.contributor.author | Titgemeyer, Evan C. | |
| dc.contributor.author | Guo, X. S. | |
| dc.contributor.author | Ding, L. M. | |
| dc.contributor.author | Wang, H. C. | |
| dc.contributor.author | Qiu, Q. | |
| dc.contributor.author | Li, Z. P. | |
| dc.contributor.author | Long, R. J. | |
| dc.contributor.authoreid | etitgeme | |
| dc.date.accessioned | 2016-03-28T19:16:06Z | |
| dc.date.available | 2016-03-28T19:16:06Z | |
| dc.date.published | 2015 | |
| dc.description | Citation: Zhou, J. W., Mi, J. D., Titgemeyer, E. C., Guo, X. S., Ding, L. M., Wang, H. C., . . . Long, R. J. (2015). A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep. Journal of Animal Science, 93(6), 3006-3017. doi:10.2527/jas2014-8865 | |
| dc.description | To study metabolic adaptation to harsh foraging conditions, an experiment was conducted to characterize and quantify N utilization efficiency and urea metabolism in Tibetan and fine-wool sheep fed 4 levels of dietary N (11.0, 16.7, 23.1, and 29.2 g N/kg DM) in 2 concurrent 4 x 4 Latin square designs. Urea kinetics were determined using continuous intrajugular infusions of (NN)-N-15-N-15-urea. Urinary excretions of total N and urea N increased linearly (P < 0.001) with dietary N and were not different between breeds (P >= 0.37). Fecal N excretion increased with dietary N for Tibetan sheep but not for fine-wool sheep (linear dietary N x breed; P < 0.05). Nitrogen retention (both amount per day and percentage of N intake) increased with increasing dietary N concentration (P < 0.001), and the rates of increase were greater in fine-wool than in Tibetan sheep (linear dietary N x breed and cubic dietary N x breed; P < 0.05). In Tibetan sheep, N retention as a percentage of intake was greatest for diets containing 16.7 g N/kg DM, whereas it was maximal for fine-wool sheep when the diet contained 23.1 g N/kg DM. Urea N entry rate, urea N recycled to the gastrointestinal tract (GIT), and urea N returned to the ornithine cycle all increased with dietary N (P < 0.05), and all were greater in Tibetan than fine-wool sheep for the 11.0 g N/kg DM diet but were greater in fine-wool than Tibetan sheep for the diet with 29.2 g N/kg DM (linear dietary N x breed; P < 0.05). Urea N excreted in feces, both amount and fraction of GIT entry rate, was less in Tibetan than finewool sheep for the 11.0 and 16.7 g N/kg DM diets but similar for diets with 23.1 or 29.2 g N/kg DM (linear dietary N x breed; P < 0.01). For the lowest-protein diet, the fraction of urea N production recycled to the GIT was greater in the Tibetan than fine-wool sheep (88% vs. 82%), but for the diet with 29.2 g N/kg DM it was greater for fine-wool than Tibetan sheep (46% vs. 39%; linear dietary N x breed; P < 0.05). Plasma urea N increased more rapidly in response to increasing dietary N concentration for fine-wool sheep than for Tibetan sheep (linear dietary N x breed; P < 0.05). Urea tubular load and the amount and percentage of urea reabsorbed by the kidney were greater in Tibetan than fine-wool sheep (P < 0.05). These results suggest that Tibetan sheep have mechanisms that allow them to utilize N more efficiently than the fine-wool sheep when dietary N is inadequate. | |
| dc.identifier.uri | http://hdl.handle.net/2097/32186 | |
| dc.relation.uri | https://doi.org/10.2527/jas.2014-8865 | |
| dc.rights | Copyright © 2015. American Society of Animal Science. | |
| dc.rights.uri | http://www.sherpa.ac.uk/romeo/issn/0021-8812/ | |
| dc.subject | Adaptation | |
| dc.subject | Dietary Nitrogen Utilization | |
| dc.subject | Qinghai-Tibetan Plateau | |
| dc.subject | Tibetan Sheep | |
| dc.subject | Urea Recycling | |
| dc.subject | Low-Quality Forage | |
| dc.title | A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep | |
| dc.type | Article |
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