Apparent digestibility and calcium and phosphorus in urine after feeding different combinations of calcium and phosphorus sources to adult dogs

Hofmann, Celina; Dobenecker, Britta und Kienzle, Ellen (2024): Apparent digestibility and calcium and phosphorus in urine after feeding different combinations of calcium and phosphorus sources to adult dogs. In: Journal of Animal Physiology and Animal Nutrition

Abstract

The present study aimed to investigate the effect of the combination of a water-soluble calcium (Ca) source (CaCl2) with a water-soluble phosphorus (P) source (NaH2PO4*2H2O, diet soluble, SOL) in comparison to a water-insoluble P source (CaHPO4*2H2O, 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 CaCl2 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 CaCl2 and NaH2PO4*2H2O. 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.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Tiermedizin > Veterinärwissenschaftliches Department > Lehrstuhl für Tierernährung und Diätetik
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0931-2439
• Sprache: Englisch