Fig. 3: Histological features of intestine samples from experimental piglets.

Groups are specified according to the treatment as in the Fig. 2. Characteristic alteration from normal histology are specified. E. coli O55 is abbreviated as O55. a Duodenum. O55—edematous lamina propria, villi with apical destruction of epithelium. Reduced count of vacuolated enterocytes. O55 + SIgA—normal histology with minimal edema in lamina propria. O55 + Fc-SC—focal moderate edematous lamina propria. O55 + Fab—moderate edema of the lamina propria. O55 + dg-SIgA—edematous lamina propria, villi congested and apical destruction of epithelium. Reduced count of vacuolated enterocytes. b Jejunum. O55—lamina propria with focal inflammatory cellularization, destructed villi and crypt epithelia and stroma. O55 + SIgA—moderate edema in lamina propria and villi congestion. O55 + Fc-SC—moderate edema of lamina propria, congestion of crypts. O55 + Fab—edematous lamina propria, moderate congestion and leukocytosis in villi stroma, minute focal changes in epithelial lining. O55 + dg-SIgA—edematous lamina propria, stroma of villi preserved, but prominent destruction of epithelial lining of villi and crypts. c Ileum. O55—edematous lamina propria, moderate activation of the lymphoid tissue. O55 + SIgA—moderate crypt hyperplasia, activation of lymphoid tissue. O55 + Fc-SC—normal histology. O55 + Fab—crypt and villi congestion and lymphocytosis. O55 + dg-SIgA—edematous lamina propria, crypt hyperplasia and epithelia erosions. d Colon. O55—heavily edematous lamina propria, enterocytes destruction in apical portion of villi. O55 + SIgA—moderate edema and enhanced cellularity of lamina propria, otherwise normal histology. O55 + Fc-SC—minute edema and cellularity of lamina propria, otherwise normal histology. O55 + Fab—normal histology. O55 + dg-SIgA—edematous and hypercellular lamina propria, congestion of villous stroma, focal apical enterocytes desquamation.