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.

Use of all-male triploid population of zebrafish (Danio rerio) for evaluation of 17α-ethinylestradiol effects.

OBJECTIVES: We tested the toxicity of ethinylestradiol, a semisynthetic estrogen used in oral contraceptives, on all-male triploid zebrafish using commercial feeds and three different doses concentrations. We aimed to determine whether ethinylestradiol peroral administration resulted in vitellogenin production and whether all-male triploid zebrafish could serve as a model species for xenoestrogen testing. METHODS: The actual concentrations of 17α-ethinylestradiol were 0.0035 (low); 0.0315 (medium) and 0.365 (high) µg/g. Positive control represented commercial feeds containing 0.0465 µg/g of ß-estradiol. The experiment lasted 8 weeks. RESULTS: Our results indicate that 17α-ethinylestradiol consumption does induce vitellogenin production in triploid zebrafish. CONCLUSIONS: The simple presence of vitellogenin is a definite symptom indicative of the potential for such changes due to the action of estrogenic substances. As such, this experiment has shown that the use of all-male triploid zebrafish populations, rather than the mixed-sex populations of other species previously used, could serve as a suitable alternative model population for controlled testing of the effects of xenoestrogens on fish.

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.