View Full Table | Close Full ViewTable 1.

Ingredients of the dry and moist diets that formed the basis of the experimental diets

 
Diet portion1
Dry extruded Moist
Brewer’s rice Beef lung
Soy protein isolate hydrolysate Poultry offal (heart, liver etc.)
Fish meal Poultry by-products
Chicken fat Poultry waste
Powdered cellulose Starch (Avongold superfine)
Hydrolyzed poultry liver Carageenan gelling agent (ricogel)
Egg powder Vitamin and mineral premix2
Vegetable oil Sodium oxalate3
Fructo-oligosaccharides
Hydroxyproline4
Taurine
Vitamins and minerals5
Preservatives and antioxidants
1Each experimental diet was obtained by mixing a complete dry extruded diet portion (high, medium, or low hydroxyproline [Hhyp, hyp, or Lhyp]) with a complete moist diet portion (low or high oxalate [Lox or Hox]). The dry extruded portions provided 94% of the daily maintenance energy requirement (MER), and the moist diet portions provided 6% of the daily MER.
2Vitamin and mineral premix contained vitamin D3, vitamin E, thiamin, pantothenic acid, pyridoxine, folic acid, Fe, Zn, Mn, I, and Se.
3Only in the Hox moist diet portion.
4Only in the Hhyp and Mhyp dry extruded portions.
5Vitamin and mineral premix contained dl-alpha-tocopherol, inositol, niacin, l-ascorbyl-2-polyphosphate, d-calcium pantothenate, biotin, pyridoxine hydrochloride, riboflavin, thiamine mononitrate, vitamin A acetate, folic acid, vitamin B12 supplement, vitamin D3 supplement, choline chloride, calcium sulfate, calcium carbonate, sodium silico aluminate, potassium chloride, zinc, proteinate, zinc oxide, calcium iodate, and sodium selenite.



View Full Table | Close Full ViewTable 2.

Analyzed composition of diets1,2

 
Diet
Component, % Hhyp-Lox Mhyp-Lox Lhyp-Lox Lhyp-Hox
Hydroxyproline 3.83 1.96 0.20 0.20
Oxalate 0.012 0.016 0.013 0.093
DM (as fed) 72.19 72.37 72.09 72.30
CP 39.66 38.99 36.78 36.69
Crude fat 15.16 15.01 15.19 15.28
Ash 6.69 6.74 6.66 6.74
Total dietary fiber 5.22 5.47 4.87 4.85
Starch 31.44 32.68 30.88 30.79
Ca 0.96 0.94 0.96 0.97
P 0.92 0.89 0.95 0.96
Na 0.66 0.66 0.65 0.68
K 0.93 0.90 0.87 0.87
Asp 3.39 3.40 3.39 3.39
Thr 1.34 1.33 1.36 1.36
Ser 1.68 1.67 1.70 1.70
Glu 5.73 5.82 5.85 5.84
Gly 1.87 1.90 1.92 1.92
Ala 1.87 1.88 1.90 1.90
Val 1.76 1.76 1.69 1.69
Ile 1.48 1.50 1.46 1.46
Leu 2.70 2.70 2.70 2.69
Tyr 1.17 1.18 1.18 1.18
Phe 1.65 1.66 1.67 1.66
His 0.80 0.80 0.81 0.80
Lys 2.10 2.12 2.10 2.10
Arg 2.35 2.42 2.40 2.39
Pro 1.95 1.84 1.89 1.89
ME,3 MJ/100 g DM 1.89 1.88 1.89 1.89
1Low oxalate (Lox) with high hydroxyproline (hyp; Hhyp-Lox), moderate hyp (Mhyp-Lox), and low hyp (Lhyp-Lox) and low hyp with high oxalate (Hox; Lhyp-Hox) diets.
2On a DM basis unless indicated otherwise.
3Calculated according to NRC (2006).



View Full Table | Close Full ViewTable 3.

Mean values for selected urine characteristics in adult cats fed experimental diets1,2

 
Diet
P-value
Item Hhyp-Lox Mhyp-Lox Lhyp-Lox Lhyp-Hox
Volume, mL·cat–1·d–1 50.63 ± 3.40a 55.70 ± 1.96a,b 57.63 ± 1.68b 56.21 ± 2.55a,b 0.017
pH2 6.98 ± 0.21 7.34 ± 0.22 7.13 ± 0.16 6.86 ± 0.17 0.298
Specific density,3 g/mL 1.061 ± 0.002 1.060 ± 0.007 1.057 ± 0.004 1.056 ± 0.004 0.081
Oxalate, mmol/L 2.26 ± 0.17c 1.57 ± 0.07b 1.11 ± 0.08a 1.22 ± 0.07a <0.001
Ca,4 mmol/L 1.69 ± 0.48 2.03 ± 0.34 2.09 ± 0.68 3.24 ± 1.04 0.194
P, mmol/L 71.28 ± 3.43 76.50 ± 2.65 76.26 ± 3.26 78.04 ± 2.72 0.050
Mg, mmol/L 2.71 ± 0.30 3.16 ± 0.41 2.85 ± 0.28 2.94 ± 0.35 0.189
Na, mmol/L 241.6 ± 4.3 235.7 ± 8.6 240.3 ± 7.6 243.1 ± 9.3 0.808
K, mmol/L 190.0 ± 5.6 195.0 ± 4.7 195.0 ± 5.4 188.8 ± 5.0 0.113
Ammonia, mmol/L 200.0 ± 5.2a,b 205.7 ± 5.1b 199.7 ± 7.1a,b 191.3 ± 7.6a 0.010
Citrate,4,5 mmol/L 2.85 ± 0.90 1.70 ± 0.31 1.70 ± 0.44 1.69 ± 0.44 0.072
Urate, mmol/L 1.25 ± 0.11 1.20 ± 0.11 1.18 ± 0.08 1.16 ± 0.09 0.122
Sulfate, mmol/L 113.3 ± 2.3a 116.1 ± 2.7a,b 119.49 ± 3.8b 115.6 ± 3.3a,b 0.035
Creatinine, mmol/L 25.56 ± 0.97 26.11 ± 0.78 25.84 ± 0.58 24.76 ± 0.78 0.114
a–cWithin a row, means without a common superscript letter differ (P < 0.05).
1Low oxalate (Lox) with high hydroxyproline (hyp; Hhyp-Lox), moderate hyp (Mhyp-Lox), and low hyp (Lhyp-Lox) and low hyp with high oxalate (Hox; Lhyp-Hox) diets.
2Values are means ± SEM (n = 8).
3Measured in nonacidified urine. Number of animals: Hhyp-Lox and Mhyp-Lox, n = 7; Lhyp-Lox, n = 6; and Lhyp-Hox, n = 5.
4Urinary Ca and citrate concentrations were log10 transformed for statistical analysis.
5After excluding 1 high citrate value of the Hhyp-Lox diet from the analysis, diet was no longer a significant factor (P = 0.072).



View Full Table | Close Full ViewTable 4.

Oxalate and Ca balance in adult cats fed experimental diet1,2

 
Diet P-value
Item Hhyp-Lox Mhyp-Lox Lhyp-Lox Lhyp-Hox
Oxalate,3 mg·cat–1·d–1
    Intake 6.55 ± 0.12a 8.56 ± 0.06c 7.26 ± 0.05b 50.83 ± 0.80d <0.001
    Fecal output 5.19 ± 0.43a 5.41 ± 0.25a 5.13 ± 0.35a 12.52 ± 2.34b <0.001
    Urinary output 10.12 ± 0.80c 7.83 ± 0.25b 5.75 ± 0.39a 6.10 ± 0.17a <0.001
    Balance –8.76 ± 0.74b –4.68 ± 0.41a –3.61 ± 0.45a 32.20 ± 2.06c <0.001
Calcium, mg·cat–1·d–1
    Intake 521.3 ± 9.4a,b 507.4 ± 3.5a 516.6 ± 3.6a,b 528.9 ± 9.3b 0.011
    Fecal output 564.3 ± 46.7 534.9 ± 27.2 513.4 ± 20.5 547.4 ± 47.3 0.709
    Urinary output 3.18 ± 0.78 4.41 ± 0.66 4.81 ± 1.60 7.40 ± 2.46 0.112
    Balance –46.20 ± 39.61 –31.97 ± 25.35 –1.61 ± 21.75 –25.89 ± 42.05 0.497
a–dWithin a row, means without a common superscript letter differ (P < 0.05).
1Low oxalate (Lox) with high hydroxyproline (hyp; Hhyp-Lox), moderate hyp (Mhyp-Lox), and low hyp (Lhyp-Lox) and low hyp with high oxalate (Hox; Lhyp-Hox) diets.
2Values are means ± SEM (n = 8).
3Oxalate intake and urinary oxalate and calcium output were log10 transformed. Fecal oxalate and calcium output and oxalate balance were 1/x transformed.