Effect of increasing dietary vitamin A on bone density in adult dogs

J Anim Sci. 1997 Nov;75(11):2980-5. doi: 10.2527/1997.75112980x.

Abstract

There has been an increase in vitamin A fortification of livestock feeds resulting in increased residual vitamin A in organ meats, which are often used in canned dog foods. The effect on bone density of feeding various concentrations of vitamin A in a canned dog food product was investigated. Thirty-two random-source dogs were assigned to four treatments in a randomized complete block design. The diets contained 15,000, 50,000, 116,000, or 225,000 IU vitamin A/1,000 kcal ME. Diets were fed up to 1 yr. Computed tomography was used to determine bone density of the right tibia at 0, 3, 6, 9, and 12 mo. Computed tomography is a more sensitive technique for determining bone density in vivo than conventional x-rays. There were no differences (P > .10) in tibia bone or marrow density in any of the dogs fed the various concentrations of vitamin A. There was no interaction of time x diet on bone density (P > .05) or bone marrow density (P > .05). In addition, there were no changes in serum alkaline phosphatase, calcium, or phosphorus. These results indicate that concentrations of vitamin A three times the recommended maximum safe amount (71,429 IU/1,000 kcal ME) are not detrimental to normal bone health in dogs. Therefore, these data support the hypothesis that canines are less sensitive to excess vitamin A in the diet than some other mammals.

MeSH terms

  • Alkaline Phosphatase / blood
  • Animals
  • Bone Density / drug effects*
  • Bone Density / physiology
  • Calcium / blood
  • Diet / veterinary*
  • Dogs / blood
  • Dogs / physiology*
  • Dose-Response Relationship, Drug
  • Female
  • Male
  • Phosphorus / blood
  • Random Allocation
  • Tibia / diagnostic imaging
  • Tibia / pathology
  • Time Factors
  • Tomography, X-Ray Computed
  • Vitamin A / administration & dosage
  • Vitamin A / pharmacology*

Substances

  • Vitamin A
  • Phosphorus
  • Alkaline Phosphatase
  • Calcium