Hofmann Celina, Dobenecker Britta, Kienzle Ellen
Department of Veterinary Science, Chair of Animal Nutrition and Dietetics, Munich, Germany.
J Anim Physiol Anim Nutr (Berl). 2025 Jan;109(1):124-129. doi: 10.1111/jpn.14038. Epub 2024 Aug 27.
The present study aimed to investigate the effect of the combination of a water-soluble calcium (Ca) source (CaCl) with a water-soluble phosphorus (P) source (NaHPO2HO, diet soluble, SOL) in comparison to a water-insoluble P source (CaHPO42HO, diet insoluble, INS) on apparent digestibility and renal excretion of Ca and P in dogs. The Ca intake was 226 mg/kg bodyweight (bw), the Ca/P ratio 1.9/1 in SOL and 2.0/1 in INS. The percentage of Ca from CaCl was 60% in SOL and 33% in INS. Eight adult Foxhound-crossbred dogs FBI, (3-5 years, bw 24-32 kg) were available. Standard digestion trials were carried out (10 days adaptation, 5 days total faecal collection). Spontaneously excreted urine was collected pre- and postprandially. In vitro water solubility of P in the mineral premixes was determined. The Ca digestibility was negative in both trials without significant differences between the groups. Apparent P digestibility was increased in group SOL (26% vs. 20% in INS). In both groups, P content in urine was higher pre- compared to postprandial, with higher concentrations in group SOL. The same was true for the P/Crea ratio. The water solubility of P in the mineral premixes used in the trials showed considerable differences: The P in premix INS was insoluble in water after 1 and after 90 min. By contrast, the P in the premix SOL was highly soluble (98%) after 1 minute. After 90 min, however, the P solubility decreased to 43%, suggesting the formation of insoluble CaP salts, presumably from CaCl and NaHPO*2HO. In conclusion, in the present study, apparent Ca digestibility in dogs was not affected by the solubility of Ca and P, while P digestibility and renal P excretion increased.
本研究旨在探讨水溶性钙（Ca）源（CaCl）与水溶性磷（P）源（NaHPO·2H₂O，日粮可溶，SOL）组合，与水不溶性P源（CaHPO₄·2H₂O，日粮不溶，INS）相比，对犬钙和磷的表观消化率及肾脏排泄的影响。钙摄入量为226mg/kg体重（bw），日粮中钙磷比在SOL组为1.9/1，在INS组为2.0/1。来自CaCl的钙在SOL组中占60%，在INS组中占33%。有8只成年猎狐犬杂交犬（FBI，3 - 5岁，体重24 - 32kg）可用。进行了标准消化试验（10天适应期，5天总粪便收集）。在餐前和餐后收集自发排出的尿液。测定了矿物质预混料中磷的体外水溶性。在两个试验中钙消化率均为负值，两组间无显著差异。SOL组的表观磷消化率有所提高（26%，而INS组为20%）。两组中，餐前尿液中的磷含量均高于餐后，且SOL组浓度更高。磷/肌酐比值情况相同。试验中所用矿物质预混料中磷的水溶性存在显著差异：INS预混料中的磷在1分钟和90分钟后均不溶于水。相比之下，SOL预混料中的磷在1分钟后高度可溶（98%）。然而，90分钟后，磷的溶解度降至43%，表明形成了不溶性磷酸钙盐，可能来自CaCl和NaHPO·2H₂O。总之，在本研究中，犬的表观钙消化率不受钙和磷溶解度的影响，而磷消化率和肾脏磷排泄增加。
