Zinc Concentration in Blood Serum of Healthy Dogs

The objective of this study was to establish a reference interval for serum zinc in dogs and to determine the factors that affected it. We collected samples from 197 clinically healthy animals of various breeds and ages and obtained information about their sex, neuter status, age, breed, diet, lifestyle, weight, and body condition score. Serum zinc concentration was measured by a colorimetric method using a clinical chemistry analyzer. We established the reference interval for serum zinc as 4.9-19.7 µmol/L. When assessing the relationship of zinc with various biochemical parameters, we found significant correlation with albumin and triacylglycerols. The only observed factor that significantly influenced serum concentration was sex. Female dogs had higher levels (median 11.0 µmol/L) than males (median 8.9 µmol/L). The difference between intact females and intact males was also significant (medians 11.6 and 9.0 µmol/L respectively), but it was only numerical for neutered animals (median of neutered females 10.7 µmol/L and of neutered males 8.7 µmol/L). Despite the general belief that homemade food for dogs contains a lower amount of zinc than a commercial one, diet did not influence zinc serum levels significantly. There was also no impact of age, breed, lifestyle, weight, or body condition score on serum zinc concentration.

Selenium and Dogs: A Systematic Review

The intent of this review is to summarize the knowledge about selenium and its function in a dog's body. For this purpose, systematic literature search was conducted. For mammals, including dogs, a balanced diet and sufficient intake of selenium are important for correct function of metabolism. As for selenium poisoning, there are no naturally occurring cases known. Nowadays, we do not encounter clinical signs of its deficiency either, but it can be subclinical. For now, the most reliable method of assessing selenium status of a dog is measuring serum or plasma levels. Levels in full blood can be measured too, but there are no reference values. The use of glutathione peroxidase as an indirect assay is questionable in canines. Commercial dog food manufactures follow recommendations for minimal and maximal selenium levels and so dogs fed commercial diets should have balanced intake of selenium. For dogs fed home-made diets, complex data are missing. However, subclinical deficiency seems to affect, for example, male fertility or recovery from parasitical diseases. Very interesting is the role of selenium in prevention and treatment of cancer.