Toxic and trace metal concentrations in liver and kidney of dogs: influence of diet, sex, age, and pathological lesions

The aim of this study was to provide data on the main toxic and trace metals in the liver and kidney of domestic dogs in Galicia, NW Spain and to evaluate the influence of diet, sex, age, and pathological lesions on metal accumulation. Samples of the liver and kidney from 77 male and female dogs, aged between 6 mo and 18 yr, were collected during ordinary necropsy. Samples were acid-digested and metal concentrations determined by inductively coupled plasma (ICP)-mass spectrometry and ICP-atomic emission spectrometry. Mean toxic metal concentrations (geometric means for liver and kidney respectively) were 11.5 and 15.8 μg/kg wet weight for As, 56.3 and 166 μg/kg for Cd, 32.7 and 51.9 μg/kg for Hg, and 60.1 and 23.6 μg/kg for Pb. For the trace metals, these concentrations were respectively 16.3 and 21.0 μg/kg for Co, 57.6 and 43.9 μg/kg for Cr, 42.1 and 5.95 mg/kg for Cu, 394 mg/kg and 95.7 mg/kg for Fe, 2.39 and 0.956 mg/kg for Mn, 0.522 and 0.357 mg/kg for Mo, 23.8 and 26.8 μg/kg for Ni, 0.686 and 1.39 mg/kg for Se, and 46.7 and 26.0 mg/kg for Zn. Cd concentrations in the kidney significantly increased with age, and Co concentrations in the liver and kidney significantly decreased with age. Hepatic Pb concentrations were significantly higher in growing (<1 yr) and old (>10 yr) dogs. Animals with pathological lesions showed significantly higher Co and lower Mn and Zn concentrations in liver than animals with-out macroscopic abnormalities. Dogs that received commercial diets in general showed low variability in hepatic mineral status compared to animals that receive homemade feeds or a mixture of commercial and homemade feeds.