Table 2.
Elemental composition of complete, wet cat and dog food.
| Major element (all ppm, mg/kg DM) | CAT (n = 113) Complete foods | DOG (n = 64) Complete foods | Statistics P-value | |||
|---|---|---|---|---|---|---|
| WET (n = 48) Median (IQR) | DRY (n = 65) Median (IQR) | WET (n = 49) Median (IQR) | DRY (n = 15) Median (IQR) | Cat vs. Dog | Wet vs. Dry | |
| Sulphur | 7269 (6348,8442) | 4989 (4124,6447) | 5211 (4442,7528) | 3302 (2925,3923) | 0.01 | <0.001 |
| Calcium | 17423 (13580,25565) | 14125 (11442,19456) | 19766 (15147,27387) | 12860 (6290,17813) | 0.21 | <0.001 |
| Phosphorus | 15715 (13297,19300) | 12365 (10730,14194) | 15672 (10471,21473) | 9555 (5051,13016) | 0.59 | <0.001 |
| Sodium | 11906 (6437,17135) | 5692 (4233,6319) | 10180 (6350,14148) | 4093 (2743,4375) | 0.63 | <0.001 |
| Magnesium | 1048 (847,1195) | 1110 (915,1357) | 1353 (1080,1762) | 1208 (1129,1360) | <0.001 | 0.86 |
| Potassium | 13376 (9943,18670) | 7686 (7174,8615) | 14857 (10102,19474) | 6254 (5567,7593) | <0.001 | <0.001 |
| TOTAL MAJOR | 73070 (61513,82443) | 47352 (41733,54338) | 70925 (54602,86870) | 41224 (25416,46955) | 0.07 | <0.001 |
| Trace element (all ppb, µg/kg DM) | ||||||
| Zinc | 154 (127,178) | 176 (143,208) | 170 (137,223) | 180 (145,214) | 0.03 | 0.21 |
| Manganese | 19.7 (11.3,24.3) | 59.6 (37.8,69.4) | 23.3 (15.9,35.4) | 57.9 (36.9,75.7) | 0.05 | <0.001 |
| Strontium | 15.0 (10.2,33.8) | 13.9 (11.4,17.0) | 20.2 (14.0,27.6) | 10.9 (9.34,13.6) | 0.04 | <0.001 |
| Rubidium | 8.45 (6.8,11.9) | 5.55 (4.16,6.76) | 9.32 (5.76,12.5) | 4.68 (2.98,6.20) | 0.002 | <0.001 |
| Molybdenum | 0.75 (0.46,0.88) | <0.64 (LOQ) | <0.64 (LOQ) | <0.64 (LOQ) | — | — |
| Chromium | <0.48 (LOQ) | <0.48 (LOQ) | <0.48 (LOQ) | 0.60 (0.43,1.28) | — | — |
| Vanadium | <0.16 (LOQ) | <0.16 (LOQ) | <0.16 (LOQ) | 0.19 (0.14,0.47) | — | — |
| Cobalt | 0.08 (0.05,0.11) | 0.08 (0.06,0.13) | 0.10 (0.06,0.14) | 0.08 (0.07,0.14) | 0.007 | 0.28 |
| TOTAL TRACE | 427 (339,610) | 501 (365,634) | 478 (433,617) | 537 (438,820) | 0.60 | 0.13 |
Data are presented as median (IQR; 1st to 3rd quartile) for each element. Duplicate, freeze-dried homogenized samples (100–200mgs) were analysed by ICP-MS, and a mean value established. Since elemental composition is presented as parts (ppm, ppb) per unit dry matter, a formal statistical comparison was conducted as a 2 (cat vs dog) ×2 (wet vs dry) factorial ANOVA, with the interaction term included. If necessary, data were log10 transformed prior to analysis in order to normalize residual errors, to avoid distributional bias. Statistical significance was accepted at P < 0.003 (Bonferroni correction for 14 elements above LOQ). Data for total trace elements includes As, Co, Cr, Cs, Cu, Fe, Mn, Mo, Rb, Se, Sr, V and Zn.