Immunogenicity And Mechanisim Of Soybean Proteantigen On The Weanling Piglets

An experiment was conducted to study the effects of soybean proteantigens on the xylose absorbability, growth performance, humoral immunity, small intestinal histamine contents, digestive enzyme activities of and small intestinal mucosa morphous in piglets which were immuned by glycinin andβ-conglycinin. The piglets were then allergized with large doses of soybean proteantigens , in order to approach the immunogenicity, mechanism and immune protective effects of glycinin andβ-conglycinin in weanling stress piglets.At frist, fifty-six"Duroc×Landrace×Yorkshire"crossbred piglets (7 d±2 of age) were randomly divided into seven groups of 8 piglets each group by weight and sex. The piglets were immunized through hypodermical injection, the physiological saline solutio was injected in control group of piglets, three doses (100, 500, 1000μg/kg·w)of glycinin andβ-conglycinin were respectively injected in six trial groups of piglets.The piglets were secondly immunized at 21 days old. All piglets were weaned on 22 days old , and blood samples were taken from the anterior vena cava at 7,21,35 days old for measuring immune indexes and cutaneous erythema diameter testing, in order to study the immunogenicity of glycinin andβ-conglycinin on weanling piglets and the optimum immune doses. Based on the experiment on the immunogenicity of glycincin andβ-conblycinin on weanling piglets, eighty eight"Duroc×Landrace×Yorkshire"crossbred piglets(7d±2 of age) were selected and randomly divided into eleven groups of 8 piglets each group by weight and sex. The piglets were immunized through hypodermical injection, the physiological saline solutio was injected in control group of piglets, 500μg/kg·w of Glycinin(11S) was respectively injected in three groups of piglets (B, C, D),the piglets were secondly immunized at 21 days old. 2500,5000μg/kg·w of 11S were respectively intramuscularly injected in the groups(C, D) of piglets at 23 days old. The groups (E, F) of piglets were also respectively intramuscularly injected with 2500,5000μg/kg·w of 11S at 23 days old. The doses and groups of 7S was the same as 11S. Body absolute weights (AW), average daily gain (ADG) in all piglets were determined on 7,21, 35 days old. All piglets were weaned on 23days old . Blood samples were taken from the anterior vena cava at 7, 21, 35 days old for measuring immune indexes (IgG,IgA, IgM,total IgE). At the end of the trial, 55 piglets (5 per group) were bled via the anterior vena cava. The proximal duodenum, middle jejunum, and proximal ileum were recollected, for measuring intestinal mucosa villus height and crypt depth, and determining digestive enzyme activities and histamine contents.The results were as follows:1. Cutaneous erythema diameter of piglets immuned with11S and 7S were 10~20mm, the allergic responses were ++.Compared with the control group, the immunogenicity of 7S and11S in trial groups enhanced significantly (P<0.01),while the immunogenicity of 7S was higher than that of 11S.2. The cutaneous erythema diameters of piglets injected with 500,1000μg/kg·w of 11S decreased significantly (P<0.01), but xylose absorbability had no significant difference. The cutaneous erythema diameters of piglets injected with 500,1000μg/kg·w of 7S decreased significantly (P<0.01), xylose absorbability enhanced effectively (P<0.01),but there had no significant difference between two doses of 7S.3. The glycinin-specific IgG in trial groups of piglets didn't produce effective antibody tite. The glycinin-specific IgG of piglets injected with 500, 1000μg/kg·w of 7S could produce effective antibody tite, but there had no significant difference between two doses of 7S.4. The AW and ADG of piglets injected with 2500, 5000μg/kg·w of 11S and 7S decreased significantly (P<0.01), and ones in the groups of piglets sensitized with 7S were significantly lower than those in the groups of piglets sensitized with 11S. Immunizing 11S and 7S could effectively enhance the growth performance, and the effect of 7S were better than that of 11S.5.The activities of amylase, chymotrypsin in the duodenum, ileum and lipase in the duodenum of piglets injected with 2500,5000μg/kg·w of 11S decreased significantly .The activities of amylase, chymotrypsin in the duodenum, jejunum and the lipase in the duodenum of piglets injected with 2500,5000μg/kg·w of 7S decreased significantly. As the dose was increasing, the enzyme activities were more severely depressed. The activities of amylase and chymotrypsin of pigets immuned by11S and 7S enhanced effectively.6.Compared with the control group, the serum IgG and total IgE antibody levels of piglets injected with 2500,5000μg/kg·w of 11S and 7S enhanced effectively, the serum IgG and total IgE antibody levels of pigets in groups of 7S were significantly higher than those of piglets in groups of 11S, and the higher dose caused more serum IgG and total IgE antibody levels, while serum IgA and IgM levels had no significant difference. The serum IgG antibody levels of pigets immuned by 11S and 7S enhanced effectively, total IgE antibody levels decreased significantly. Compared with the groups of 11S, the serum IgG antibody levels of pigets in groups of 7S enhanced significantly, total IgE antibody levels decreased significantly, but serum IgA and IgM levels had no significant difference.7. The histamine contents in duodenum and ileum of piglets injected with 2500, 5000μg/kg·w of 11S decreased significantly, the histamine contents in duodenum and jejunum of piglets injected with 2500, 5000μg/kg·w of 7S decreased significantly (P<0.01), and the higher dose released more histamine. The histamine contents of pigets immuned by 11S and 7S enhanced effectively.8. Injecting glycinin could injure mucous membrane in duodenum and ileum, injectingβ-conglycinin could injuere mucous membrane in duodenum and jejunum , intestinal villi were highly descented, crypt darken. Higher dose caused the villi more severely injuerd. The villi in small intestine of piglets immuned by 11S and 7S were highly enhanced and crypt were effectively descented.In conclusion, glycinin andβ-conglycinin-induced hypersensitivity wereⅠ,Ⅲmixed mode, the severity of the hypersensitive reactions was concerned with the dose of soybean allergic proteins, and the higher dose cuased more severe anaphylactic symptoms. The immunogenicity ofβ-conglycinin was higher than that of glycinin. The optimum immune doses of the 11S and 7S for pigets were 500μg/kg·w, and the protective effect ofβ-conglycinin was effectively better than that of glycinin.