Allergens and intestinal damage induced by soybean antigen proteins in weaned piglets

This study was conducted to investigate the effects of soybean antigen proteins on serum cytokine levels and claudin-1 distribution in the intestine of weaned piglets. Seventy piglets (24 d of age) were randomly divided into seven groups. Piglets in group A were fed a basal diet, in groups B, C and D were fed the basal diet supplemented with β-conglycinin; and in groups E, F, G were fed the basal diet supplemented with glycinin. Blood samples were collected and analysed for IFN-γ, IL-2, IL-4 and IL-6 levels on day 24, 26, 28 and 30. At the end of the trial, five piglets per group were sacrificed and the small intestine was collected to evaluate intestinal claudin-1 distribution and OD of the relative staining positivity. β-Conglycinin and glycinin decreased the growth performance in piglets by decreasing ADFI, ADG and increasing F/G. Serum levels of IL-2, IL-4 and IL-6 in β-conglycinin and glycinin groups ranged from 126.067 to 144.067 ng • L−1, 31.798 to 44.360 ng • L−1 and 36.360 to 40.482 ng • L−1 on day 24, 26 and 30. However, serum IFN-γ levels were negatively correlated with soybean antigen proteins supplementation levels ranged from 6.956 to 15.361 ng • L−1. The treatment groups had lower OD values of claudin-1 than those of the control group. The β-conglycinin groups had lower distribution and OD values than the glycinin groups at similar antigen protein supplementation levels. These results suggest that β-conglycinin and glycinin damage the intestinal mucosal immune barrier in weaned piglets.