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Effect of different fatty acids on the proliferation and cytokine production of peripheral blood mononuclear cells (PBMC) of dairy cows.

N. Vanacker



Effect of different fatty acids on the proliferation and cytokine production of peripheral blood mononuclear cells (PBMC) of dairy cows.
N. Vanacker*1,2, R. Blouin1, C. Ster2, P. Lacasse2,1. 1Université de Sherbrooke Sherbrooke, QC, Canada, 2Agriculture and Agrifood Canada Sherbrooke, QC, Canada.

During the transition period, dairy cows often experience negative energy balance which induces metabolic and immunological disturbances. Our previous work has shown a relationship between the inhibition of immune functions and the increase in blood nonesterified fatty acid (NEFA) concentrations. We evaluated the effect of 11 fatty acids (palmitoleic, myristic, palmitic, stearic, oleic, linoleic, docosahexaenoic, conjugated linoleic, lauric, eicosapentanoic and linolenic acids) as well as a mix that represent the NEFA profile observed during the transition period, at different concentrations (0, 50, 100 and 250 µM) on proliferation and cytokines secretion of lymphocytes. To assess lymphoproliferation, PBMC from 5 healthy cows (166—189 DIM) were isolated, stimulated with the mitogenic lectin concanavalin-A (ConA) and incubated for 72 h with or without fatty acids. As evidenced by flow cytometry, all fatty acids, except lauric acid, significantly reduced proliferation of PBMC (P < 0.05) as the doses increased. The most detrimental effect on PBMC was observed with linoleic and stearic acids, which were able to inhibit proliferation at the lowest doses (50 µM). With regard to cytokine secretion, we found that the concentration of interleukin-4 in culture supernatant of ConA-stimulated PBMC was considerably reduced upon exposure to the lowest dose (50 µM) of oleic and palmitoleic acids (P < 0.05) for 24 h while a dose of 100 µM was necessary for eicosapentanoic acid, the NEFA mixture and myristic acid (P < 0.05). PBMC also showed decreased (P < 0.05) secretion of interferon-γ in response to lauric, linolenic, palmitoleic and stearic acids at 50 µM and myristic acid at 100 µM. Overall, our study confirms that NEFA, such as those of 18 carbons, have a negative impact on some lymphocyte functions, whereas others, like lauric acid, have less effects. We did not observed positive effect for any of the fatty acids on the tested immune functions.

Keywords: lymphocytes, cytokine, immunosuppression.

Biography: I am a Belgian student who came to Canada after completing my Bachelor degree in agronomy to carry out a Master's degree in molecular and cellular biology. I am currently doing my Ph.D. at the University of Sherbrooke. My research project take place at the Sherbrooke Agriculture and Agri-Food Canada Research Center during which I mainly focus on the immune system of dairy cows.