Doctor of Philosophy (PhD)


Veterinary Medical Sciences - Pathobiological Sciences

Document Type



Inflammation is a component of the innate immune response. However, severe or prolonged inflammation can be detrimental. Dietary n-3 fatty acid supplementation has proven clinical benefits in chronic inflammatory diseases, most likely due to reduced synthesis of inflammatory mediators and inhibition of lymphocyte proliferation and function. The purposes of this study were to characterize alterations in inflammatory mediator production, and lymphocyte proliferation, in dogs fed a diet consisting of 0.65% n-3 fatty acids (DMB) with an n-6:n-3 fatty acid ratio of 3.4:1. Fifteen dogs were randomly assigned to one of three dietary groups for twelve weeks. Group Sunflower oil received a basal diet supplemented with 12.4g of sunflower oil/day. Groups Fish oil and Fish oil +E each received the same basal diet supplemented with 0.6g of sunflower oil and 7g of menhaden fish oil. Group Fish oil + E also received 0.18g of vitamin E. IL-1, IL-6, TNF-á, PGE2, and PAF were evaluated both in mononuclear cell culture, and in serum after in vivo stimulation with lipopolysaccharide. Lymphocyte proliferation was evaluated by incorporation of tritiated thymidine as well as sequential halving of a fluorochrome dye, CFSE, using flow cytometry. Potential adverse effects of dietary n-3 fatty acid supplementation were assessed through serum vitamin E concentrations, plasma lipid peroxidation, platelet aggregation, and standard hematologic and serum biochemical parameters. Serum levels of IL-6 and PGE2 as well as mononuclear cell culture levels of PGE2 were significantly higher among dogs of Group Sunflower oil compared to dogs in Groups Fish oil or Fish oil + E. Lymphocyte proliferation as evaluated by flow cytometry was significantly reduced in Group Fish oil at 12 weeks compared to Groups Sunflower oil and Fish oil + E. There was no significant diet effect on platelet aggregation, lipid peroxidation, or hematologic and biochemical parameters, with the exception of decreased triglycerides in Group Fish oil. These data demonstrate that a significant degree of immunomodulation is possible with a safe dietary intake and ratio of n-3 fatty acids. Future studies should focus on the clinical role of dietary n-3 fatty acid supplementation for the treatment of inflammatory diseases and hyperlipidemia.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Glenna E. Mauldin