TitleEffects of dietary n-6 and n-3 fatty acids and vitamin E on the immune response of healthy geriatric dogs.
Publication TypeJournal Article
Year of Publication2003
AuthorsHall, JA, Tooley, KA, Gradin, JL, Jewell, DE, Wander, RC
JournalAm J Vet Res
Date Published2003 Jun
KeywordsAdjuvants, Immunologic, Aging, alpha-Tocopherol, Animals, Blood Cell Count, Diet, Dogs, Fatty Acids, Omega-3, Fatty Acids, Omega-6, Fatty Acids, Unsaturated, Female, Hemocyanins, Hypersensitivity, Delayed, Leukocyte Count, Phagocytosis, T-Lymphocyte Subsets, Tocopherols

OBJECTIVE: To determine the effect of dietary n-6 to n-3 fatty acid ratios and alpha-tocopheryl acetate concentration on immune functions andT cell subpopulations in healthy dogs.

ANIMALS: Thirty-two 7- to 10-year old female Beagles.

PROCEDURE: For 17 weeks, dogs were fed food that contained low (1.4:1) or high (40:1) ratios of n-6 to n-3 fatty acids in combination with 3 concentrations of all rac-alpha-tocopheryl acetate (low, 17 mg/kg of food; medium, 101 mg/kg; high, 447 mg/kg). Dogs were inoculated twice with a keyhole limpet hemocyanin suspension at 13 and 15 weeks.

RESULTS: After 12 weeks, dogs consuming low concentrations of alpha-tocopheryl acetate had lower percentages of CD8+ T cells, compared with dogs consuming medium or high alpha-tocopheryl acetate concentrations. Also, dogs consuming low alpha-tocopheryl acetate concentrations had higher CD4+ to CD8+ T cell ratios. On day 4 of week 15, the percentage of CD8+ T cells was highest in dogs fed medium concentrations of alpha-tocopheryl acetate, compared with other dogs; however, the CD4+ to CD8+ T cell ratio was higher only in dogs fed low concentrations of alpha-tocopheryl acetate with high concentrations of n-3 fatty acids. Dogs consuming low concentrations of n-3 fatty acids with medium concentrations of alpha-tocopheryl acetate had the largest delayed-type hypersensitivity (DTH) skin test response.

CONCLUSIONS AND CLINICAL RELEVANCE: An optimum amount of dietary alpha-tocopheryl acetate concentration, regardless of the dietary n-6 to n-3 fatty acid ratio, stimulates the CD8+ T cell population. Effects of an optimum amount of dietary alpha-tocopheryl acetate concentration on the DTH response are blunted by dietary n-3 fatty acids.

Alternate JournalAm J Vet Res
PubMed ID12828263