Effects of β-Conglycinin on intestinal structure and intestinal permeability in Rhynchocypris lagowski Dybowski

The purpose of this study was to evaluate the effects of beta-conglycinin on intestinal permeability, intestinal morphology and the expression of tight junction protein in Rhynchocypris lagowski Dybowski. 750 Rhynchocypris lagowski Dybowski (4.61 +/- 0.01 g) were divided into 5 groups (CK, beta-20, beta-40, beta-60 and beta-80 groups) and fed with 5 diets contained, respectively (0, 20, 40, 60 and 80 g/kg), beta-conglycinin for 8 weeks. These results showed dietary beta-conglycinin could destroy the structural integrity of intestine, cause villus to break and shrink, and the epithelium and lamina propria to separate. Simultaneously, compared with CK group, the levels of Diamine oxidase (DAO), 5-Hydroxytryptamine (5-HT), D-lactic acid (D-LA) and Endothelin-1 (ET-1) in serum were significantly increased in beta-20, beta-40, beta-60 and beta-80 groups (P < .05). In proximal intestines (PI), the expression of Zonula occludens-1 (ZO-1) and Occludin-b was significantly reduced, and lamina propria width was significantly increased in beta-60 and beta-80 groups (P < .05), and fold height, muscular layer thickness and the expression of Claudin were significantly decreased in beta-40, beta-60 and beta-80 groups (P < .05), and the expression of Occludin-a was significantly decreased in beta-20, beta-40, beta-60 and beta-80 groups (P < .05); in addition, the expression of ZO-1 in PI was significantly increased in beta-20 and beta-40 groups (P < .05). In mid intestines (MI), fold height and the expression of ZO-1 and Claudin were significantly reduced, and lamina propria width was significantly increased in beta-40, beta-60 and beta-80 groups (P < .05), and the expression of ZO-1 was significantly increased in beta-20 groups (P < .05), and muscular layer thickness and the expression of Occludin-a and Occludin-b were significantly decreased in beta-20, beta-40, beta-60 and beta-80 groups (P < .05). In distal intestines (DI), fold height and the expression of ZO-1, Claudin, Occludin-a and Occludin-b were significantly reduced, and lamina propria width was significantly increased in beta-20, beta-40, beta-60 and beta-80 groups (P < .05), and muscular layer thickness was significantly reduced in beta-40, beta-60 and beta-80 groups (P < .05). In summary, dietary beta-conglycinin had negative effects on tight junctions, intestinal permeability and morphology. Moreover, the negative effects of beta-conglycinin on intestines from high to low were DI, MI and PI in our study.

Automated summary

The study showed that dietary beta-conglycinin has negative effects on tight junctions, intestinal permeability, and morphology in Rhynchocypris lagowski Dybowski. The negative effects decrease from distal intestines, mid intestines to proximal intestines.