[Effects of a supplementation on sodium chloride or ammonium chloride on urolithic potential in the rabbit].
OBJECTIVE
Reduction of urolithic potential by means of increased water intake and urine dilution through supplementation of sodium chloride (NaCl) or decrease of urine pH by supplementation of ammonium chloride (NH4Cl) in rabbits.


METHODS
Sixteen female, 6-month-old dwarf rabbits received the following three feeding regimens in a random order: complete feed without supplements = control; complete feed + 10 g NaCl/kg feed = NaCl; complete feed + 2.5 g NH4Cl/kg feed = NH4Cl. The diets were fed ad libitum over a period of 27 days without roughage. Water was provided ad libitum by a drinker. A 14-day wash-out-period (hay feeding) was performed between the different diets. Blood, faeces, and urine were collected at the beginning of each feeding period, after 21-day adaptation to the respective diet, and after the 3-day collection period. The following parameters were analysed: water and food intake as well as acid-base balance and mineral content in blood, urine, and faeces.


RESULTS
NaCl supplementation numerically increased the daily water intake from 40.5 ± 14.4 ml/kg body weight (BW) (control) up to 49.5 ± 14.3 ml/kg BW and significantly increased the daily urine volume from 16.9 ± 7.8 ml/kg BW (control group) to 21.1 ± 7.4 ml/kg BW. The specific gravity of urine samples from NaCl supplementation decreased from 1.060 ± 0.008 to 1.044 ± 0.008. NH4Cl supplementation did not induce significant changes in urine pH, blood acid-base parameters, or calcium retention. Relative supersaturations (RSS) for calcium oxalate and calcium phosphate showed no significant changes after treatment. RSS for struvite increased from 360 ± 735 (after hay feeding) to 3312 ± 6188 on control feeding, 2910 ± 4913 with NaCl supplementation, and 3022 ± 6635 with NH4Cl supplementation (p < 0.05).


CONCLUSIONS
NaCl supplementation significantly increased the urine volume and decreased its specific gravity. Therefore, NaCl supplementation might be an additional dietary treatment to increase the elimination of urine crystals in rabbits. NH4Cl supplementation did not induce acidification of the urine.
Cornelia
C
Rückert
Roswitha
R
Siener
Martin
M
Ganter
Manfred
M
Coenen
PD Dr. med. vet. Ingrid Vervuert, Institut für Tierernährung, Ernährungsschäden und Diätetik der Universität Leipzig, An den Tierklinken 9, 04103 Leipzig, E-Mail: ingrid.vervuert@vetmed.uni-leipzig.de.
Ingrid
I
Vervuert
D000643:Ammonium Chloride / Q000494:pharmacology*; D000818:Animals; D019587:Dietary Supplements; D004326:Drinking / Q000187:drug effects*; D005260:Female; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology*; D016482:Urinalysis / Q000662:veterinary; D014545:Urinary Calculi / Q000517:prevention & control / Q000652:urine / Q000662:veterinary*; D014556:Urine / Q000737:chemistry
D000643:Ammonium Chloride; D012965:Sodium Chloride
RSS; Urolithiasis; calcium; dietary management; urine dilution; urine supersaturation; water intake