title: Effects of a high-protein diet versus dietary supplementation with ammonium chloride on struvite crystal formation in urine of clinically normal cats.
abstract: OBJECTIVE
  To evaluate the effects of a high-protein diet versus dietary supplementation with ammonium chloride (NH4Cl) on struvite crystal formation in the urine of clinically normal cats by measuring the urine concentration of hydrochloric acid (HCl)-insoluble sediment, urine pH, struvite activity product (SAP), number of struvite crystals in urine, and urine volume.
  
  
  METHODS
  23 healthy adult cats.
  
  
  METHODS
  Urine was fractionated by centrifugation with subsequent extraction of the sediment with 1 N HCl (study 1). Diets containing either 29% crude protein or 55% crude protein were fed to cats in a crossover trial of 3 weeks/period (study 2). Diets supplemented with either sodium chloride (NaCl) or NH4Cl were fed, by use of a 3 x 3 Latin-square design with 3 wk/period (study 3). In studies 2 and 3, urine samples were collected for the last 7 days of each period.
  
  
  RESULTS
  The HCl-insoluble sediment contained Tamm-Horsfall glycoprotein (THP; study 1). The high-protein diet (study 2) and dietary supplementation with NH4Cl (study 3) resulted in a decrease in urine pH, SAP, and the number of struvite crystals in urine. However, the high-protein diet decreased urine concentrations of HCl-insoluble sediment containing THP (study 2), in contrast to the NH4Cl supplementation that increased urine volume without a significant effect on the urine concentration of the HCl-insoluble sediment (study 3).
  
  
  CONCLUSIONS
  Our results indicate that compared with dietary supplementation with NH4Cl, the high-protein diet is preferable as a urine acidifier for the prevention of struvite crystal formation in clinically normal cats.
authors.affiliation: Laboratory of Nutrition, Azabu University School of Veterinary Medicine, 1-17-71 Fuchinobe, Sagamihara 229-8501, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Funaba
authors.forename: Takayo
authors.initials: T
authors.lastname: Yamate
authors.forename: Yuka
authors.initials: Y
authors.lastname: Hashida
authors.forename: Kodenta
authors.initials: K
authors.lastname: Maki
authors.forename: Ken
authors.initials: K
authors.lastname: Gotoh
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kaneko
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Tsunenori
authors.initials: T
authors.lastname: Iriki
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hatano
authors.forename: Matanobu
authors.initials: M
authors.lastname: Abe
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology*; D000821:Animal Feed; D000818:Animals; D002371:Cat Diseases / Q000517:prevention & control / Q000652:urine; D002415:Cats; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000494:pharmacology*; D019587:Dietary Supplements; D005260:Female; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000652:urine*; D008297:Male; D010710:Phosphates / Q000652:urine*; D000069877:Struvite; D014545:Urinary Calculi / Q000517:prevention & control / Q000652:urine / Q000662:veterinary
chemical_list: D004044:Dietary Proteins; D017616:Magnesium Compounds; D010710:Phosphates; D000643:Ammonium Chloride; D000069877:Struvite