Serum Ferritin in Obese Dogs: Changes and Comparison with Other Analytes

SIMPLE SUMMARY: Canine obesity, defined as a weight greater than 15% of the ideal, is associated with decreased quality of life, longevity, and other complications. However, the mechanisms causing these alterations are not fully understood. In obese humans, increased concentrations of ferritin in serum have been found; however, this has been poorly explored in dogs. In this study, ferritin levels from lean/normal weight (CG, n = 55) and overweight/obese dogs (OG, n = 37) were evaluated, together with complete hemogram and biochemical analyses. Higher ferritin concentrations were observed in the OG group in comparison to the CG. The increases in ferritin, together with higher haematocrit and erythrocyte mean corpuscular volume, could indicate tissue hypoxia in obese dogs. ABSTRACT: Canine obesity is the most common nutritional disorder and is associated with decreased quality of life and longevity as well as comorbidities including cardiorespiratory, endocrine, oncologic, or orthopaedic disorders. Ferritin is a major acute-phase protein in dogs, increasing during inflammation; however, it could also be affected by other conditions, including trauma, iron metabolism dysregulations, neoplasia, or hypoxia. Higher ferritin levels have been reported in obese humans, but ferritin has not been explored in canine obesity. To evaluate the possible changes in serum ferritin in canine obesity, ferritin levels from lean/normal weight (CG, n = 55) and overweight/obese dogs (OG, n = 37) were measured, together with complete hemogram and biochemical analyses. Statistically significant higher ferritin levels (1.2-fold) were found in OG (median, (interquartile range), 204 (166–227.5) µg/L) in comparison to CG animals (172 (137–210) µg/L)), with median levels of ferritin in OG dogs above the reference range for healthy animals in our laboratory (60–190 µg/L). In addition, statistically significant higher mean corpuscular volume (MCV), mean cell haemoglobin concentration (MCHC), total proteins, globulins, haptoglobin, total ferric fixation capacity (TIBC), alkaline phosphatase (ALP), butyrylcholinesterase (BChE), triglycerides, and calcium were observed in OG in comparison to CG. The higher levels in ferritin, together with higher TBIC, haematocrit, and MCV, could indicate tissue hypoxia in obese dogs.