Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, CH-8057 Zurich, Switzerland.
Department of Animal Science, Aarhus University, AU Foulum, Blichers Allé 20, PO Box 50, DK-8830 Tjele, Denmark; Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 32, DK-2000 Frederiksberg, Denmark.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Jul;257:110941. doi: 10.1016/j.cbpa.2021.110941. Epub 2021 Mar 29.
Rumen content stratification and the degree of dissociation of particle and fluid retention in the reticulorumen differ between 'moose-type' and 'cattle-type' ruminant species. These differences are not strictly linked to diet, except for a seeming limitation of 'moose-type' ruminants to a browsing niche. Nevertheless, these differences can be plausibly linked to other observed differences in ruminants, such as the intraruminal papillation pattern, or the size of the omasum. However, many of the corresponding measures are still only available for a restricted number of species. Here, we investigated the dry matter (i.e., the inverse of the moisture) concentration in forestomach contents of 10 blackbuck (Antilope cervicapra) and 7 Arabian sand gazelle (Gazella subgutturosa marica), and quantified the rumen papillation pattern. The blackbucks had distinct rumen contents stratification, with more moisture in ventral than in dorsal contents (difference 3.6% units, P < 0.001), whereas this difference was much less pronounced in the sand gazelles (0.6% units, P = 0.227). While reticulum contents were particularly moist in both species, omasum contents were particularly dry in sand gazelles, but did not differ in moisture from rumen contents in the blackbuck. This species is an outlier among ruminants due to its extremely small omasum. The intraruminal papillation pattern did not differ between blackbucks and sand gazelles and showed a surface enlargement factor (SEF) in the dorsal rumen of 27-28% of the SEF in the Atrium ruminis. Compared to data on digesta retention in the same species, the findings are in line with the overall concept of a high fluid throughput causing a distinct stratification of rumen contents and intraruminal papillation, and necessitating a large omasum for fluid re-absorption. However, the data also show that individual species may not correspond to all the assumptions of the concept, suggesting taxon-specific differences between species. Reasons for these differences cannot be linked to a dietary grass-browse spectrum, but may lie in evolutionary contingency.
反刍胃内容物的分层以及网胃中颗粒和液体的分离程度在“驼鹿型”和“牛型”反刍动物物种之间存在差异。这些差异与饮食没有严格的联系，除了“驼鹿型”反刍动物似乎局限于食草生态位。然而，这些差异可以与反刍动物的其他观察到的差异合理地联系起来，例如瘤胃乳头模式或瓣胃的大小。然而，许多相应的措施仍然只适用于少数几种物种。在这里，我们研究了 10 只印度黑羚（Antilope cervicapra）和 7 只阿拉伯沙瞪羚（Gazella subgutturosa marica）的前胃内容物的干物质（即水分的倒数）浓度，并量化了瘤胃乳头模式。印度黑羚的瘤胃内容物分层明显，腹部分的水分比背部分多（差异 3.6%单位，P<0.001），而沙瞪羚的这种差异小得多（0.6%单位，P=0.227）。虽然两种物种的网胃内容物都特别潮湿，但瓣胃内容物在沙瞪羚中特别干燥，但在水分方面与黑羚的瘤胃内容物没有差异。由于其非常小的瓣胃，该物种是反刍动物中的一个异常值。黑羚和沙瞪羚的瘤胃乳头模式没有差异，并且在背侧瘤胃中具有 27-28%的 Atrium ruminis 中表面放大因子（SEF）的 SEF。与同一物种中消化物保留的数据相比，这些发现符合高流体通量导致瘤胃内容物和瘤胃乳头明显分层以及需要大的瓣胃进行液体再吸收的总体概念。然而，数据还表明，个别物种可能不符合该概念的所有假设，这表明物种之间存在分类特异性差异。这些差异的原因不能与饮食中的草-食谱联系起来，但可能在于进化的偶然性。
