Effects of dietary n-6 and n-3 fatty acids and vitamin E on the immune response of healthy geriatric dogs.
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.


METHODS
Thirty-two 7- to 10-year old female Beagles.


METHODS
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
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.
Hall
Jean A
JA
Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802, USA.
Tooley
Katie A
KA
Gradin
Joseph L
JL
Jewell
Dennis E
DE
Wander
Rosemary C
RC
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000375:Aging / Q000276:immunology*; D000818:Animals; D001772:Blood Cell Count / Q000662:veterinary; D004032:Diet; D004285:Dogs / Q000276:immunology*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007958:Leukocyte Count / Q000662:veterinary; D010587:Phagocytosis; D016176:T-Lymphocyte Subsets / Q000187:drug effects; D024505:Tocopherols; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*
D000276:Adjuvants, Immunologic; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin; D024502:alpha-Tocopherol; D024505:Tocopherols