Induction of immune responses and allergic reactions in piglets by injecting glycinin

Comparative effects of soy protein concentrate, enzyme-treated soybean meal, and fermented soybean meal replacing animal protein supplements in feeds on growth performance and intestinal health of nursery pigs

BACKGROUND

Soy protein supplements, with high crude protein and less antinutritional factors, are produced from soybean meal by different processes. This study evaluated the comparative effects of various soy protein supplements replacing animal protein supplements in feeds on the intestinal immune status, intestinal oxidative stress, mucosa-associated microbiota, and growth performance of nursery pigs.

METHODS

Sixty nursery pigs (6.6 ± 0.5 kg BW) were allotted to five treatments in a randomized complete block design with initial BW and sex as blocks. Pigs were fed for 39 d in 3 phases (P1, P2, and P3). Treatments were: Control (CON), basal diet with fish meal 4%, 2%, and 1%, poultry meal 10%, 8%, and 4%, and blood plasma 4%, 2%, and 1% for P1, P2, and P3, respectively; basal diet with soy protein concentrate (SPC), enzyme-treated soybean meal (ESB), fermented soybean meal with Lactobacillus (FSBL), and fermented soybean meal with Bacillus (FSBB), replacing 1/3, 2/3, and 3/3 of animal protein supplements for P1, P2, and P3, respectively. Data were analyzed using the MIXED procedure in SAS 9.4.

RESULTS

The SPC did not affect the BW, ADG, and G:F, whereas it tended to reduce (P = 0.094) the ADFI and tended to increase (P = 0.091) crypt cell proliferation. The ESM did not affect BW, ADG, ADFI, and G:F, whereas tended to decrease (P = 0.098) protein carbonyl in jejunal mucosa. The FSBL decreased (P < 0.05) BW and ADG, increased (P < 0.05) TNF-α, and Klebsiella and tended to increase MDA (P = 0.065) and IgG (P = 0.089) in jejunal mucosa. The FSBB tended to increase (P = 0.073) TNF-α, increased (P < 0.05) Clostridium and decreased (P < 0.05) Achromobacter and alpha diversity of microbiota in jejunal mucosa.

CONCLUSIONS

Soy protein concentrate, enzyme-treated soybean meal, and fermented soybean meal with Bacillus could reduce the use of animal protein supplements up to 33% until 7 kg body weight, up to 67% from 7 to 11 kg body weight, and entirely from 11 kg body weight without affecting the intestinal health and the growth performance of nursery pigs. Fermented soybean meal with Lactobacillus, however, increased the immune reaction and oxidative stress in the intestine consequently reducing the growth performance.

Integrated Microbiota and Metabolome Analysis to Assess the Effects of the Solid-State Fermentation of Corn-Soybean Meal Feed Using Compound Strains

Solid-state fermentation is known to improve plant-based feed nutritional quality; however, the association between microbes and metabolite production in fermented feed remains unclear. We inoculated corn-soybean-wheat bran (CSW) meal feed with Bacillus licheniformis Y5-39, Bacillus subtilis B-1, and lactic acid bacteria RSG-1. Then, 16S rDNA sequencing and untargeted metabolomic profiling were applied to investigate changes in the microflora and metabolites, respectively, and their integrated correlations during fermentation were assessed. The results indicated that trichloroacetic acid soluble protein levels showed a sharp increase, while glycinin and β-conglycinin levels showed a sharp decrease in the fermented feed, as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Pediococcus, Enterococcus, and Lactobacillus were predominant in the fermented feed. Overall, 699 significantly different metabolites were identified before and after fermentation. Arginine and proline, cysteine and methionine, and phenylalanine and tryptophan metabolism were the key pathways, with arginine and proline metabolism being the most important pathway in the fermentation process. By analyzing the correlation between the microbiota and metabolite production, lysyl-valine and lysyl-proline levels were found to be positively correlated with Enterococcus and Lactobacillus abundance. However, Pediococcus was positively correlated with some metabolites contributing to nutritional status and immune function. According to our data, Pediococcus, Enterococcus, and Lactobacillus mainly participate in protein degradation, amino acid metabolism, and lactic acid production in fermented feed. Our results provide new insights into the dynamic changes in metabolism that occurred during the solid-state fermentation of corn-soybean meal feed using compound strains and should facilitate the optimization of fermentation production efficiency and feed quality.

Variations of Soybean Meal and Corn Mixed Substrates in Physicochemical Characteristics and Microbiota During Two-Stage Solid-State Fermentation

Corn germ meal (CGM) and corn gluten feed (CGF) are the two main corn byproducts (CBs) obtained from corn starch extraction. Due to their high fiber content, low protein content, and severe imbalance of amino acid, CBs are unable to be fully utilized by animals. In this study, the effect of microorganism, proteases, temperature, solid–liquid ratio, and time on nutritional properties of CB mixture feed (CMF) was investigated with the single-factor method and the response surface method to improve the nutritional quality and utilization of CBs. Fermentation with Pichia kudriavzevii, Lactobacillus plantarum, and neutral protease notably improved the nutritional properties of CMF under the fermentation conditions of 37°C, solid–liquid ratio (1.2:1 g/ml), and 72 h. After two-stage solid-stage fermentation, the crude protein (CP) and trichloroacetic acid-soluble protein (TCA-SP) in fermented CMF (FCMF) were increased (p < 0.05) by 14.28% and 25.53%, respectively. The in vitro digestibility of CP and total amino acids of FCMF were significantly improved to 78.53% and 74.94%, respectively. In addition, fermentation degraded fiber and provided more organic acids in the CMF. Multiple physicochemical analyses combined with high-throughput sequencing were performed to reveal the dynamic changes that occur during a two-stage solid-state fermentation process. Generally, Ascomycota became the predominant members of the community of the first-stage of fermentation, and after 36 h of anaerobic fermentation, Paenibacillus spp., Pantoea spp., and Lactobacillales were predominant. All of these processes increased the bacterial abundance and lactic acid content (p < 0.00). Our results suggest that two-stage solid-state fermentation with Pichia kudriavzevii, Lactobacillus plantarum, and protease can efficiently improve protein quality and nutrient utilization of CMF.

Antigenic activity and epitope analysis of β-conglycinin hydrolyzed by pepsin

BACKGROUND

Soybean is among the 'big eight' allergenic foods, and β-conglycinin, the main antigenic protein of soybean, has high levels of antigenic activity. Why the antigenic activity of soybean β-conglycinin is not eliminated by enzymatic hydrolysis is not clear. In this study, changes in the molecular composition and antigenicity of β-conglycinin hydrolyzed by pepsin were analyzed and it was determined whether complete sequential epitopes exist in the resulting hydrolysates. The nature and antigenic activity of protein subunits obtained after β-conglycinin hydrolysis were also assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and competitive enzyme-linked immunosorbent assay, respectively.

RESULTS

The residual antigenic activity of β-conglycinin was 52%, α'- and α-subunits completely disappeared, the 49 kDa fraction partially disappeared, and peptides measuring 27 and 23 kDa were newly formed after 60 min of enzymatic hydrolysis. Prolonged enzymatic hydrolysis did not result in remarkable changes in these peptides; thus, the peptides show some resistance to enzymatic hydrolysis. The amino acid sequences of the peptide chains were analyzed by matrix-assisted laser desorption / ionization-time of flight mass spectrometry and aligned with the related sequences in the corresponding protein and antigen databases. Ten complete sequential epitopes were identified in the residual 49 kDa fraction, of these epitopes, two were from α-subunits and eight were from β-subunits.

CONCLUSION

The presence of complete sequential epitopes in hydrolysates obtained from the enzymatic hydrolysis of soybean is an important reason for the incomplete disappearance of the antigenic activity of β-conglycinin. © 2020 Society of Chemical Industry.

Laparoscopic procedures impact on mast cell mediators, extracellular matrix and adhesion scoring system in rats

Background

Laparoscopic procedures under certain pressure have the potential to cause intra-abdominal adhesions. However, the pathomechanism of this disorder is unknown. Release of mast cell mediators due to mast cell degranulation is thought to be the cause.

Materials and methods

Thirty male Sprague-Dawley rats were grouped into five groups (n = 6 per group): one control group and four intervention groups to which 60 min insufflation was performed using carbon dioxide at 5, 8, 10 and 12 mmHg. Seven days after laparoscopy, we euthanized and evaluated the levels of histamine, tryptase, and chymase of peritoneal fluid, the thickness of ECM of peritoneal tissue, and intraabdominal adhesion scoring system.

Results

Histamine and tryptase levels in peritoneal fluid were significantly higher at the 10- and 12 mm Hg intervention compared to control (histamine: 0.50 ± 0.35 vs. 0.41 ± 0.41 vs. 0.04 ± 0.02 ng/mL, respectively; and tryptase: 0.69 ± 0.11 vs. 0.65 ± 0.05 vs. 0.48 ± 0.02 ng/ml respectively). The ECM was significantly thicker in the intervention groups at 10- and 12-mm Hg compared to control (71.3 [66.7–85.2] vs. 48.4 [34.5–50.3] vs. 10.25 [8.7–12.1] μm, respectively). Moreover, the intra-abdominal scoring was also significantly higher in the intervention groups at 10- and 12 mm Hg compared to control (4 [0–4] vs. 4.5 [4–5], vs. 0, respectively).

Conclusions

Laparoscopic procedures increase the release of mast cell mediators in peritoneal fluid, the thickness of ECM and intraabdominal adhesion scoring in rats, implying that it might increase the possibility of intrabdominal adhesion in humans.

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Laparoscopic procedures at specific pressures potentially cause intra-abdominal adhesion, however, its pathomechanism is still challenging to understand.

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Laparoscopic procedures increase the release of mast cell mediators in peritoneal fluid, the thickness of ECM and intraabdominal adhesion scoring in rats.

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Our findings imply that laparoscopic procedures might increase the possibility of intrabdominal adhesion in humans.

Effects of 7S and 11S on the intestine of weaned piglets after injection and oral administration of soybean antigen protein

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.