Dietary Interventions Against PCV2-induced Immunosuppression using conjugated linoleic acid

Bassaganya-Riera, J., R. Hontecillas, P.G. Halbur, K.J. Yoon, and R.M. Progranichniy (2003) Dietary Interventions Against PCV2-induced Immunosuppression using conjugated linoleic acid. Proceedings of the 1^st Asian Pig Veterinary Society Congress. Seoul, Korea

Two animal trials were conducted to examine the effect of dietary CLA-supplementation on immune protection from PCV2 infection or immune response to experimental vaccination for PCV2 in pigs. Following dietary supplementation with either soybean oil or CLA, pigs fromeach diet group were either challenged (experiment 1) with PCV2 or vaccinated (experiment 2) with UV-inactivated PCV2 antigens. After the challenge, the degree of lymphoid depletion of the lymph nodes and blood as well as interstitial pneumonia in the lungs was assessed and scored. The phenotype of depleted lymphocyte subsets was characterized by flow cytometry. Proliferation of lymphocytes in response to ex vivo stimulation with a recombinant capsid protein of PCV2 was assessed by PKH67 and blastogenesis assays. Antibody responses to PCV2 were determined using an ELISA and IFA. No differences in stimulation indices were detected between control and CLA-supplemented diets at optimal antigenic stimulation levels (i.e., live viral challenge). In contrast, CLA supplementation in diet enhanced lymphocyte proliferation to viral antigens in the context of sub-optimal virus-specific cellular responses (i.e., vaccination with inactivated virus). These findings are suggestive that the CLA-induced enhancement of T cell responses could be maximized in immunocompromised pigs.