Supplementing Plant-Based Docosahexaenoic Acid From Bioactive Canola, with Arachidonic Acid, in Maternal Diet Is Beneficial for Immune System of the 3 Week BALB/c Offspring

OBJECTIVES: To understand the mechanism behind the programming effect of docosahexaenoic acid (DHA, derived from genetically modified Canola) supplementation (along with arachidonic acid, AA) during breastfeeding period on immune development of 3 wk pups using BALB/c mouse. METHODS: Pregnant mice, 5 days prior to parturition, were randomized to consume DHA diet (1% DHA, 1% AA w/w total fat, n = 10) or control diet (0% DHA and AA, n = 12) for 3-wk post-parturition (suckling period). At birth, pups were cross fostered to ensure equal pups per dam. Dams and 3-wk old pups were euthanized and spleen was collected for analysis. Immune cells were isolated to study ex-vivo cytokine production by innate (bacterial stimulant, lipopolysaccharide; LPS) and adaptive (lymphocyte stimulant phorbol myristate acetate + ionomycin; PMAi) immune cell. Cytokine were measured by Meso Scale (electrochemiluminescent assay) and splenocyte phenotyping by flow cytometry. Data was analyzed using Student's T test. RESULTS: Food intake, bodyweight, spleen weight and splenocyte count showed no diet effect in dams or pups. DHA diet in dams resulted in lower proportion of CD86+ (effector cells, P = 0.01) and higher proportion of CD138 + plasma B cells (P < 0.001) in splenocyte than control, however, total B cells (CD45R+) and total T cells (CD3+) showed no diet effect. Although, ex-vivo cytokine production (IL-1β, IL2, IL-4, IL-5, IL-6, IL-10, IL-12, CXCL-1, TNFα and IFN-γ) by splenocytes to PMAi in dams did not differ between diet groups. In pups, splenocytes proportion of effector T cells (CD3 + CD28+) was 20% lower, whereas mature B cells (CD19 + and IgG+) was higher in DHA diet group (P's < 0.05). Additionally, dendritic cell (CD103+) was 30% higher in DHA group with no difference in other innate cells. DHA diet significantly improved inflammatory response of innate cells to LPS (TNFα, IFNγ and IL-1β) and overall response of adaptive cells to PMAi (∼ 50% higher IL-10, IL-6, and CXCL-1) compared to control 3-wk pups. CONCLUSIONS: Adaptive immune cell response improved in 3-wk pups from dams supplemented with dietary DHA and AA, despite lower effector T cells, this may be due to higher antigen presentation function of mature B cells and dendritic cells. FUNDING SOURCES: Alberta Canola, NSERC, and product from Nuseed; ALES AGES (awarded to Patel, D.).