The aim of this study was to examine the effects of a bioactive compound, 5-aminolevulinic acid (5-ALA), which has been reported to exhibit an immune-boosting effect, using a classical live swine fever (CSF) vaccine experimental model in pigs. Methods: First, the effect of two different 5-ALA doses was evaluated by measuring the blood CSF viral load in male and female micro miniature pigs after vaccination with live vaccines. The CSF vaccine had a low inducing effect on antibody production in

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... males, which improved after administration of 5-ALA by enhancing Th2 immunity as indicated by elevated interleukin-10 levels. Next, using male micro miniature pigs, the change in body weight was measured from the time before inoculation with the live vaccine to 28 days after inoculation, and the pattern of IgM and IgG antibody production after 5-ALA administration was examined. Results: Preventive doses of 5-ALA enabled the continuous production of IgG antibodies at the same rate as found in control pigs not receiving 5-ALA; however, the switch to IgG production was delayed during 5-ALA treatment. Oral administration of 5-ALA kept the testing male pigs healthy, showing normal growth. Conclusions: This suggested that the heme synthesis-promoting effects of 5-ALA simultaneously promoted the conversion of B cells into plasma cells.Keywords: functional food, 5-ALA, human equivalent dose, pig, classical swine fever