β-Conglycinin (7S) and glycinin (11S) are known to induce a variety of hypersensitivity reactions involving the skin, intestinal tract, and respiratory tract. The present study aimed to identify the mechanism underlying the development of allergy to soybean antigen proteins, using piglets as an animal model. Weaned "Duroc × Landrace × Yorkshire" piglets were fed a diet supplemented with 7S or 11S to investigate the signaling pathway involved in intestinal damage in piglets. Results showed that serum nitric oxide (NO), tumor necrosis factor-α (TNF-α), and caspase-3 levels were significantly higher in 7S- and 11S-fed piglets compared to those in suckling or weaned ones. mRNA, protein, and phosphorylation levels of nuclear factor-kappa B (NF-κB), p38, and Jun N-terminal kinase (JNK) were higher in 7S- and 11S-fed piglets than in suckling and weaned ones. Overall, our results indicate that 7S and 11S damaged the intestinal function in piglets through their impact on NF-κB, JNK, and p38 expression.

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Soybeans are used increasingly in food products because of their health benefits. In this study, we investigated the effect of soybean antigen protein on weaned piglet intestine. Seventy piglets were randomly divided into seven groups with 10 piglets each. At 7 and 14 days of age, groups A–C were injected with saline, and D–G were intramuscularly injected with or orally administered 7S or 11S. Groups B–G were artificially sensitized by dietary 7S or 11S. At 27 days, the small intestinal tissues were collected to determine levels of histamine, sIgA protein, and IgA mRNA. Histamine in B–G was significantly decreased in the duodenum and ileum. Moreover, sIgA expression was higher in all groups than in A, with B/C>D–G and F/G>D/E; the trend in IgA expression was similar. Collectively, these results indicated that soybean antigen protein‐immunizing agents decrease sIgA and IgA levels. Additionally, the effect of injection immunization occurred prior to that of oral immunization.