Department of Veterinary Science, Ludwig-Maximilians-Universität, Munich, Germany.
Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
J Anim Physiol Anim Nutr (Berl). 2018 Apr;102(2):370-379. doi: 10.1111/jpn.12844. Epub 2017 Nov 26.
To investigate the relationship between faecal calcium (Ca) and phosphorus (P) excretion in different mammalian species, a meta-analysis on digestibility data derived from the literature was conducted. Seventy-three studies on carnivores, omnivores, large and small hindgut fermenters, ruminants and hippos (a total of 21 mammalian species, precondition for inclusion dietary Ca/P ratio 1.5/1 - 3.0/1) were analysed for Ca and P digestibility. Dietary Ca/P ratios were lower than faecal Ca/P ratios in carnivores, omnivores, ruminants and hippos. In hindgut fermenters, dietary Ca/P ratios were higher than faecal Ca/P ratios, indicating higher intestinal Ca absorption in these species. In all species investigated, there was a significant positive relationship between Ca intake and faecal Ca excretion and between P intake and faecal P excretion. In the biologically relevant range, these equations predicted lower faecal Ca losses in hindgut fermenters than ruminants, for faecal P vice versa. In all species, faecal Ca and P excretion correlated significantly. In carnivores, this highly linear correlation was exceptionally strong (R² = .92). Yet, the linearity of the correlation was questionable in omnivores and ruminants. Possibly, the strong linear correlation of faecal Ca and P excretion in carnivores is due to the formation of insoluble Ca/P complexes in their relatively short and simple gastrointestinal tract. Another hypothesis is that in carnivores, Ca homeostasis relies on modifying bone turnover to a higher degree than on changes in intestinal Ca absorption. For the formation of bone matrix, a constant ratio of Ca and P absorption is of advantage.
为了研究不同哺乳动物粪便钙（Ca）和磷（P）排泄之间的关系，对文献中获得的消化率数据进行了荟萃分析。对 73 项关于肉食动物、杂食动物、大/小型后肠发酵者、反刍动物和河马（总共 21 种哺乳动物，纳入条件为饲粮 Ca/P 比 1.5/1-3.0/1）的研究进行了 Ca 和 P 消化率分析。肉食动物、杂食动物、反刍动物和河马的饲粮 Ca/P 比低于粪便 Ca/P 比。在后肠发酵者中，饲粮 Ca/P 比高于粪便 Ca/P 比，表明这些物种的肠道 Ca 吸收更高。在所研究的所有物种中，Ca 摄入量与粪便 Ca 排泄量之间以及 P 摄入量与粪便 P 排泄量之间均存在显著正相关关系。在生物学相关范围内，这些方程预测后肠发酵者的粪便 Ca 损失低于反刍动物，而粪便 P 则相反。在所有物种中，粪便 Ca 和 P 排泄量均显著相关。在肉食动物中，这种高度线性相关性异常强烈（R²=.92）。然而，在杂食动物和反刍动物中，这种相关性的线性存在疑问。可能，由于在相对较短且简单的胃肠道中形成了不溶性 Ca/P 复合物，肉食动物中粪便 Ca 和 P 排泄的强线性相关性。另一种假设是，在肉食动物中，Ca 稳态依赖于更程度地改变骨转换，而不是改变肠道 Ca 吸收。对于骨基质的形成，Ca 和 P 吸收的恒定比例是有利的。
