Change of ruminal sodium transport in sheep during dietary adaptation
Change of ruminal sodium transport in sheep during dietary adaptation
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DOI：
10.1080/17450390802506885
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发表时间：
2009-01-01
影响因子：
2
通讯作者：
Martens, Holger
中科院分区：
文献类型：
--
作者：
Etschmann, Benjamin;Suplie, Annabelle;Martens, Holger
瘤胃适应在奶牛生产周期中起着重要的作用。在这项研究中，功能性瘤胃上皮适应后，从干草喂养（随意）的混合干草/精料饮食的变化的时间过程进行了监测，通过测量Na+运输率在Ussing室实验。共18只绵羊接受不同时期的混合干草/精料饲喂，范围从0周（对照;随意采食干草）至12周（每天800 g干草加800 g精料，分两等份）。对于每只动物，在混合干草/精料饲喂期后测量钠的净吸收。净钠转运，Jnet，从2.150.43（对照）显著上升到3.731.02eq cm-2 h-1后，1周的干草/精料混合饲料，4周后达到峰值水平的4.550.50Eq cm-2 h-1和3.920.36eq cm-2 h-1后，12周的混合饲料。因此，73%的功能适应发生在饮食改变后的第一周。这与形态适应大约需要六周才能达到峰值水平的发现形成明显对比。因此，早期功能适应混合干草/浓缩物饮食的特点是增强钠吸收率每上皮细胞。当长时间饲喂精饲料时，瘤胃上皮细胞（乳头的数量和大小）的增殖效应可能会进一步提高吸收率。早期功能性适应，没有表面积扩大的瘤胃上皮似乎是第一步，在应对改变发酵率后饮食的变化。
Rumen adaptation plays an important role in the productive cycle of dairy cattle. In this study, the time course of functional rumen epithelium adaptation after a change from hay feeding (ad libitum) to a mixed hay/concentrate diet was monitored by measuring Na+ transport rates in Ussing chamber experiments. A total of 18 sheep were subjected to different periods of mixed hay/concentrate feeding ranging from 0 weeks (control; hay ad libitum) to 12 weeks (800g hay plus 800g concentrate per day in two equal portions). For each animal, the net absorption of sodium was measured following the mixed hay/concentrate feeding period. Net Na transport, Jnet, significantly rose from 2.150.43 (control) to 3.731.02eq cm-2 h-1 after one week of mixed hay/concentrate diet, reached peak levels of 4.550.50Eq cm-2 h-1 after four weeks and levelled out at 3.920.36eq cm-2 h-1 after 12 weeks of mixed feeding. Thus, 73% of functional adaptation occurred during the first week after diet change. This is in apparent contrast to findings that morphological adaptation takes approximately six weeks to reach peak levels. Hence, early functional adaptation to a mixed hay/concentrate diet is characterised by enhanced Na absorption rates per epithelial cell. Absorption rates are likely to be further enhanced by proliferative effects on the rumen epithelium (number and size of papillae) when concentrate diets are fed over longer periods of time. Early functional adaptation without surface area enlargement of the rumen epithelium appears to be the first step in coping with altered fermentation rates following diet change.