ESTABLISHING THE ZEBRAFISH MODEL OF FOODBORNE-ENTERITIS AND IMAGING THE INVOLVED IMMUNE CELLS’ RESPONSE

Foodborne enteritis caused by plant protein substitution has become one of the major limiting factors in aquaculture. The purpose of this study was to establish a disease model for better understanding the local intestinal immune effect of fish foodborne enteritis. In this study, zebrafish lines of fluorecence labled immune cells (either innate or adaptive populations) were used to construct soybean induced enteritis model, during either the developmental stage of innate or adaptive immunity, respectively. Analysis was carried for both pathology, including both histological and molecular level, and the response of immune cell. Current results showed that in the aspect of innate immunity, zebrafish responded to acute enteritis by recruiting neutrophils and macrophages in the hindgut and inducing the morphological change of macrophages, which indicated the transition between anti-inflammatory/pro-inflammatory states and was also coincidant with expresional changing of cytokines. One the other hand, for the adaptive immunity, soybean meal diet promoted lymphocytes’ aggregation to the hindgut, for both immature lymphocytes and mature T lymphocytes. The mophological change, which suggested the transition of anti-inflammatory/pro-inflammatory states, was observed among the lymphocytes population. Furthermore, at the level of pathology, soybean meal caused damage on intestinal barrier indicated by result of HE staining. In additon to patholocially disrupted barrier, qPCR results molecularly indicated the increased apoptosis of intestinal cells, disturbed tight junction, as well as compensatory hyperplasia for intestinal epithelial cell, paralled with increased expression of proinflammatory factors. It was worth mentioning that during the development stage of adaptive immunity in zebrfish, the intestinal immune regulation, indicated by the increased expression of foxp3, il-10, and tgf-beta, in order to develop the immune tolerance has worked during food borne enteritis. In conclution, this study has provided a effective and visible model of food-borne enteritis in zebrafish and thus set up a platform for the development of related functional feed additives in fish.