Objective: To examine the effects of age, sex, breed, liver histopathology, and year of death/sample collection on liver copper concentrations in dogs fed various commercial dog foods throughout their lives.
Sample: During necropsy, 336 samples were collected between the years 2006 and 2022 from dogs that were fed a variety of commercial dog foods on the market. This study utilized all liver samples available and did not require specific criteria for sample selection.
Methods: Liver samples (n = 336) were analyzed as dry weight for copper concentration by inductively coupled plasma-optical emission spectrometry. The potential effects of animal age and year of death/collection (scatterplots and linear regression), sex, liver histopathology (t test), and breed (ANOVA) on liver copper concentration were assessed.
Results: Labrador Retrievers had lower liver copper concentrations than Beagles, but mixed breeds did not differ from Beagles or Labrador Retrievers. Analysis of year of death showed that liver copper concentrations decreased from 2006 through 2011, increased in 2012, decreased in 2013, and peaked in 2016, decreasing thereafter. Mean copper concentration of abnormal liver histopathology samples was lower than mean copper concentrations of normal liver histopathology samples. Age (12.9 ± 2.6 years) and sex had no effect on liver copper concentrations. Of note, some samples showed abnormal hepatic pathology.
Clinical relevance: Liver copper concentrations varied significantly with breed and year of death; however, average liver copper concentrations of each year were within normal. However, this was a retrospective population study and diet histories of the dogs were unknown, requiring further investigation.
Keywords: canine; copper; hepatopathy; liver; toxicity.