•Anti-glycinin monoclonal antibodies were produced based on soy-free mouse model.•A sandwich ELISA is developed based on Mab 6F2 for detection of soybean glycinin.•The assay shows high affinity and specificity in comparison with previous methods.•We analysed the content of glycinin in 469 soybean seeds and five soybean products.This study performs a sandwich ELISA for detection of trace amounts of glycinin in soybean products. We designed a soy-free mouse model to produce anti-glycinin monoclonal antibodies with high affinity and specificity. Using the monoclonal antibody as coating antibody, with the rabbit anti-glycinin polyclonal antibody as a detected antibody, the established sandwich ELISA showed high specificity for glycinin with minimum cross-reactions with other soy proteins. The practical working range of the determination was 3–200 ng/mL with detection limit of 1.63 ng/mL. The regaining of glycinin in spiked soybean samples were between 93.8% and 103.3% with relative standard deviation less than 8.3% (intra-day) and 10.5% (inter-day). The developed assay was used in analysing 469 soybean samples and five soybean products under different processing. The assay provides a specific and sensitive method for screening of glycinin and allows for further investigation into hypersensitive mechanisms to soybean proteins.

The present study was conducted to evaluate the effects of early administration of Lactobacillus fermentum I5007 on intestinal development and microbial composition in the gastrointestinal tract using a neonatal piglet model. Full-term 4 day old piglets, fed with milk replacer, were divided into a control group (given placebo of 0.1% peptone water) and a L. fermentum I5007 group (dosed daily with 6 × 109 CFU/mL L. fermentum I5007). The experiment lasted 14 days. On day 14, a significant increase in the jejunum villous height (583 ± 33 vs 526 ± 18) and increases in the concentrations of butyrate (7.55 ± 0.55 vs 5.33 ± 0.39) and branched chain fatty acids in the colonic digesta were observed in piglets in the L. fermentum I5007 treatment (P < 0.05). mRNA expression of IL-1β (1.29 ± 0.29 vs. 0.62 ± 0.07) in the ileum were lower after 14 days of treatment with L. fermentum I5007. Denaturing gradient gel electrophoresis (DGGE) revealed that L. fermentum I5007 affected the colonic microbial communities on day 14 and, in particular, reduced numbers of Clostridium sp. L. fermentum I5007 play a positive role in gut development in neonatal piglets by modulating microbial composition, intestinal development, and immune status. L. fermentum I5007 may be useful as a probiotic for application in neonatal piglets.

A monoclonal antibody (Mab), 4B2, against soybean glycinin was prepared using the preliminary extracted natural glycinin as the immunogen in our previous study. Herein, we established a novel method for the purification of glycinin by Mab 4B2-based immunoaffinity chromatography. The characteristics of the purified glycinin were identified by SDS-PAGE, Western blot, and histamine release assay. Glycinin was successfully isolated from soybeans with a yield of 16.8% and a purity of 93.8%, which were significantly higher than those produced using other traditional procedures. The acidic polypeptides of the purified glycinin can be recognized by the Mab 4B2, but not the basic polypeptides. In addition, the histamine release ratio of the purified glycinin was similar to that of natural glycinin, which indicated that the purified glycinin maintained its biological activities. Further study revealed that the Mab/gel ratios ranging from 6.0 to 12.0 mg/mL were suitable for the isolation of glycinin using immunoaffinity chromatography. Taken together, this new method based on immunoaffinity chromatography could be used for high-yield and high-purity natural glycinin production and would facilitate future study on the mechanism of soybean-induced food allergy.

This study was conducted to evaluate the effects of grape-seed procyanidins in controlling weaning diarrhea using a rat model. Weaned rats were fed either the basal diet or basal diet supplemented with either 250 mg/kg grape-seed procyanidins or 2000 mg/kg ZnO. Treated rats had better performance with a reduced incidence of diarrhea (P < 0.05). Both ZnO and grape-seed procyanidins significantly reduced urinary lactulose to mannitol ratios (P < 0.05) and enhanced the mRNA and protein expression of the intestinal mucosal tight junction proteins Ocln/ZO-1 (P < 0.05). Grape-seed procyanidins increased the activities of SOD, GSH-Px, and GSH while decreasing the level of MDA in the intestinal mucosa (P < 0.05). Furthermore, an in vitro investigation revealed that supplementation with grape-seed procyanidins in IEC-6 intestinal epithelial cells significantly enhanced the expression of Ocln/ZO-1 under H2O2-induced oxidative stress. Collectively, these results indicate that grape-seed procyanidins have the potential to prevent weaning diarrhea by reducing intestinal permeability and improving antioxidant indices.

The purpose of this study was to evaluate the attenuation effects of consuming a small dose of lipoic acid on soybean glycinin-induced hypersensitivity using a rat model. Sensitized by gavage with glycinin, weaned rats were orally supplemented with the diet containing 12.5 μg of lipoic acid/g (per diet). Results showed that untreated, sensitized rats demonstrated an increase in the level of serum IgE, the level of histamine release, and incidence of diarrhea and reduced growth performance compared with the controls (P < 0.05). Lipoic acid significantly (P < 0.05) improved growth performance while reducing mast cell numbers, the level of serum IgE, and the level of histamine release. Lipoic acid supplementation altered the balance of cytokines, attenuated the Th2-type immune response, and amended the ratio of CD4+ to CD8+ T cells (P < 0.05). Our results suggest that a small dose of lipoic acid has the potential to be an immunomodulator to prevent soybean-induced allergies.