The use of n-alkane markers to estimate the intake and apparent digestibility of ryegrass and Kikuyu by horses
The use of n-alkane markers to estimate the intake and apparent digestibility of ryegrass and Kikuyu by horses
复制标题
DOI：
10.4314/sajas.v32i1.3791
复制
发表时间：
2002
影响因子：
0.8
通讯作者：
D. M. Stevens;J. V. Ryssen;J. Marais
中科院分区：
文献类型：
--
作者：
D. M. Stevens;J. V. Ryssen;J. Marais
对正烷烃标记（剂量标记、三十二烷、C32、牧草标记 C31、C33 和 C35）技术在马饲料采食量和消化率研究中的应用进行了评估。马消化道中食糜的平均保留时间是在单剂量 C32 后测定的。然后采用正烷烃技术来估计饲喂新鲜多年生黑麦草（Lolium perenne）、新鲜基库尤草（Pennisetum Clandestinum，Hochst）和基库尤干草的马的干物质摄入量和消化率。马体内 C32 标记的平均保留时间估计为 27.9 小时。平均而言，C32 的粪便回收率略高于奇数链烷烃 (0.80-0.85)，为 0.89，但差异并不显着。使用正烷烃标记的烷烃技术可以很好地估计干物质摄入量，例如对于新鲜黑麦草，测得的摄入量为 8.86?0.23 千克，根据 C31:C32 比例估计的摄入量为 7.9?1.9 千克，根据 C32:C33 比例估计的摄入量为 8.3?1.4 千克。然而，所加标记物的较高回收率的影响需要进一步研究。如果计算中包含了内部烷烃粪便回收不完全的因素，则表观干物质消化率的估计值与测量值吻合良好。结论是烷烃技术适合估计放牧条件下的采食量。然而，必须知道粪便中回收的膳食烷烃的比例，才能准确估计表观消化率。在放牧条件下，当采集粪便样本来测量粪便烷烃浓度时，这将是一个问题。南非动物科学杂志 Vol.32(1) 2002: 50-56
The n-alkane marker (dosed marker, dotriacontane, C32, herbage markers C31, C33 and C35) technique was evaluated for use in feed intake and digestibility studies with horses. The mean retention time of digesta in the digestive tract was determined in horses following a single dose of C32. The n-alkane technique was then employed to estimate dry matter intake and digestibility in horses fed fresh perennial ryegrass (Lolium perenne), fresh Kikuyu grass (Pennisetum clandestinum, Hochst) and Kikuyu hay. The mean retention time of the C32 marker in the horses was estimated to be 27.9 h. On average the C32 had a slightly greater faecal recovery of 0.89 than the odd-chain alkanes (0.80-0.85), though the differences were not significant. The alkane technique, using the n-alkane markers, gave good estimates of dry matter intake, e.g. for fresh ryegrass the measured intake was 8.86?0.23 kg and the estimated intakes from the C31:C32 ratio, 7.9?1.9 kg and from the C32:C33 ratio, 8.3?1.4 kg. However, the effect of the higher recovery of the dosed marker needs further investigation. The estimates of apparent dry matter digestibility corresponded well with measured values, provided the factor for the incomplete faecal recovery of the internal alkanes was included in the calculation. It was concluded that the alkane technique is suitable to estimate feed intake under grazing conditions. However, the proportion of dietary alkanes recovered in the faeces has to be known to obtain an accurate estimate of apparent digestibility. This would be a problem under grazing conditions when faecal grab samples are taken for measuring faecal alkane concentrations. South African Journal of Animal Science Vol.32(1) 2002: 50-56