Effects of potassium chloride and potassium bicarbonate in the diet on urinary pH and mineral excretion of adult cats.
Low dietary K levels have been associated with increasing renal Ca excretion in humans, indicating a higher risk of calcium oxalate (CaOx) urolith formation. Therefore, the present study aimed to investigate whether dietary K also affects the urine composition of cats. A total of eight adult cats were fed diets containing 0·31 % native K and 0·50, 0·75 and 1·00 % K from KCl or KHCO₃ and were evaluated for the effects of dietary K. High dietary K levels were found to elevate urinary K concentrations (P<0·001). Renal Ca excretion was higher in cats fed the KCl diets than in those fed the KHCO₃ diets (P=0·026), while urinary oxalate concentrations were generally lower in cats fed the KCl diets and only dependent on dietary K levels in cats fed the KHCO₃ diets (P<0·05). Fasting urine pH increased with higher dietary K levels (P=0·022), reaching values of 6·38 (1·00 % KCl) and 7·65 (1·00 % KHCO₃). K retention was markedly negative after feeding the cats with the basal diet (-197 mg/d) and the 0·50 % KCl diet (-131 mg/d), while the cats tended to maintain their balance on being fed the highest-KCl diet (-23·3 mg/d). In contrast, K from KHCO₃ was more efficiently retained (P=0·018), with K retention being between -82·5 and 52·5 mg/d. In conclusion, the dietary inclusion of KHCO₃ instead of KCl as K source could be beneficial for the prevention of CaOx urolith formation in cats, since there is an association between a lower renal Ca excretion and a generally higher urine pH. The utilisation of K is distinctly influenced by the K salt, which may be especially practically relevant when using diets with low K levels.
Department of Veterinary Medicine, Institute of Animal Nutrition, Freie Universität Berlin, Königin-Luise-Straße 49, 14195 Berlin, Germany.
Nadine
N
Passlack
Mars GmbH, Eitzer Straße 215, 27283 Verden, Germany.
Thomas
T
Brenten
Institute of Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany.
Konrad
K
Neumann
Department of Veterinary Medicine, Institute of Animal Nutrition, Freie Universität Berlin, Königin-Luise-Straße 49, 14195 Berlin, Germany.
Jürgen
J
Zentek
D000137:Acid-Base Imbalance / Q000378:metabolism / Q000517:prevention & control / Q000652:urine / Q000662:veterinary; D000818:Animals; D001639:Bicarbonates / Q000009:adverse effects / Q000627:therapeutic use*; D002118:Calcium / Q000032:analysis / Q000652:urine*; D002129:Calcium Oxalate / Q000378:metabolism / Q000652:urine; D002415:Cats; D004032:Diet / Q000009:adverse effects / Q000662:veterinary*; D005243:Feces / Q000737:chemistry; D005260:Female; D006863:Hydrogen-Ion Concentration; D007684:Kidney Tubules / Q000378:metabolism*; D008297:Male; D053040:Nephrolithiasis / Q000378:metabolism / Q000517:prevention & control / Q000652:urine / Q000662:veterinary*; D010070:Oxalates / Q000378:metabolism / Q000652:urine; D011188:Potassium / Q000032:analysis / Q000652:urine*; D011189:Potassium Chloride / Q000009:adverse effects / Q000627:therapeutic use*; D017680:Potassium Compounds / Q000009:adverse effects / Q000627:therapeutic use*; D011191:Potassium Deficiency / Q000378:metabolism / Q000517:prevention & control / Q000652:urine / Q000662:veterinary
D001639:Bicarbonates; D010070:Oxalates; D017680:Potassium Compounds; D002129:Calcium Oxalate; D011189:Potassium Chloride; C026329:potassium bicarbonate; D011188:Potassium; D002118:Calcium