Böswald Linda, Kienzle Ellen
Lehrstuhl für Tierernährung und Diätetik, Ludwig-Maximilians-Universität München.
Tierarztl Prax Ausg G Grosstiere Nutztiere. 2019 Aug;47(4):223-229. doi: 10.1055/a-0947-8799. Epub 2019 Aug 21.
Species differences in calcium and phosphorus metabolism can be expressed via dietary and faecal calcium/phosphorus ratios. The aim of the present meta-analysis was to use faecal Ca/P ratios as an indicator of phosphorus digestibility in growing pigs as a simple diagnostic tool. This tool can be useful in cases of suspected phosphorus deficiency but adequate dietary calcium and phosphorus contents.
Studies (n = 34) with phytase-supplemented (PHYT; n = 110) and non-supplemented control (CON; n = 106) diets were analysed for dietary intake, faecal excretion and apparent digestibility of calcium and phosphorus. A modified Lucas-test was used for both minerals plotting intake against faecal excretion (mg/kg body weight).
For calcium, there was no significant difference between PHYT and CON (p = 0.29) while in accordance with literature, the relative faecal phosphorus excretion was significantly lower in PHYT than CON (p < 0.01). Faecal calcium/phosphorus ratios were calculated and grouped according to the animals' body weight and apparent phosphorus digestibility (body weight ≤ 30 kg: apparent phosphorus digestibility ≤ 60 % and > 60 %; body weight > 30 kg: apparent phosphorus digestibility ≤ 40 % and > 40 %).
Data distribution as displayed in a box plot shows that - given a dietary Ca/P ratio of > 1.2 - faecal Ca/P ratios of > 1.5 in pigs with a body weight of ≤ 30 kg and of > 1.2 in pigs with a body weight of > 30 kg indicate a high apparent digestibility of phosphorus of > 60 % and > 40 %, respectively.
When faecal samples reveal a Ca/P ratio above the indicated thresholds, a low phosphorus digestibility is unlikely. No conclusion regarding the apparent phosphorus digestibility can be drawn from faecal Ca/P ratios below this threshold.
钙和磷代谢的物种差异可通过日粮和粪便钙/磷比值来体现。本荟萃分析的目的是将粪便钙/磷比值用作生长猪磷消化率的指标，作为一种简单的诊断工具。该工具在怀疑磷缺乏但日粮钙和磷含量充足的情况下可能有用。
分析了34项研究，这些研究使用了添加植酸酶的日粮（PHYT；n = 110）和未添加植酸酶的对照日粮（CON；n = 106），测定了日粮摄入量、粪便排泄量以及钙和磷的表观消化率。使用改良的卢卡斯试验对两种矿物质进行分析，绘制摄入量与粪便排泄量（毫克/千克体重）的关系图。
对于钙，PHYT组和CON组之间无显著差异（p = 0.29），而与文献一致，PHYT组的相对粪便磷排泄量显著低于CON组（p < 0.01）。计算了粪便钙/磷比值，并根据动物体重和表观磷消化率进行分组（体重≤30千克：表观磷消化率≤60%和> 60%；体重> 30千克：表观磷消化率≤40%和> 40%）。
箱线图显示的数据分布表明，当日粮钙/磷比值> 1.2时，如果体重≤30千克的猪粪便钙/磷比值> 1.5，体重> 30千克的猪粪便钙/磷比值> 1.2，则分别表明磷的表观消化率较高，> 60%和> 40%。
当粪便样本显示钙/磷比值高于指定阈值时，磷消化率低的可能性不大。低于该阈值的粪便钙/磷比值无法得出关于表观磷消化率的结论。
