title: Effect of increasing dietary vitamin A on bone density in adult dogs.
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.
authors.affiliation: Division of Nutritional Sciences, University of Illinois, Urbana-Champaign, 61801, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Cline
authors.forename: G L
authors.initials: GL
authors.lastname: Czarnecki-Maulden
authors.forename: J M
authors.initials: JM
authors.lastname: Losonsky
authors.forename: C R
authors.initials: CR
authors.lastname: Sipe
authors.forename: R A
authors.initials: RA
authors.lastname: Easter
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000097:blood; D004032:Diet / Q000662:veterinary*; D004285:Dogs / Q000097:blood / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D010758:Phosphorus / Q000097:blood; D011897:Random Allocation; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014801:Vitamin A / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D014801:Vitamin A; D010758:Phosphorus; D000469:Alkaline Phosphatase; D002118:Calcium