TTW project 15566: Fishing for functional feed: understanding the immune modulatory effects of novel feed ingredients to secure fish health
To date, fish represent 16 percent of all animal protein consumed globally and the consumption of fish as animal protein is expected to grow rapidly. To meet the increasing demand more and more fish are farmed, instead of captured. To feed these fish, the aquaculture industry is continuously searching for novel sustainable and healthy alternatives for (ecologically and economically) expensive feed components such as fishmeal. However, alternatives such as soybean meal often cause intestinal inflammation in fish. To date, not much is known on the interaction of dietary components and the intestinal immune system and health of fish. In this project, we will use the zebrafish to pre-screen feed ingredients for their potential to secure fish health. The use of young and thus transparent zebrafish of transgenic reporter fish lines allows for non-invasive in vivo monitoring of inflammation as well as direct assessment of gut barrier function. We will generate much-needed fundamental scientific data on the interaction between diet and gut immunity in an important model fish species. Our partner Skretting ARC (world leader in the manufacture and supply of aquaculture feeds) will apply this knowledge to further develop health promoting diets for aquaculture species such as salmon.
NWO-ENW Klein subsidie
Keeping the peace at the mucosal surface. How does host immunity control bad bugs?
From birth onwards all organisms are colonized by microbial species. These microbial species mainly consist of benign bacteria (symbionts) that help digest food by converting and liberating inaccessible nutrients. Additionally, the microbial community (microbiota) prevents opportunistic pathogens to colonize by occupying different niches and competing for food. In response to colonizing bacteria, the host immune system develops (it learns to discriminate between friend and foe) and in turn the immune system can shape the microbial community by removing pathogenic species. Interestingly, our research and that of others, has shown that during early colonization some opportunistic pathogenic species (pathobionts) are able to colonize the gut, and are not removed, but are actively repressed by specific cells of the immune system. This seems to be a highly conserved vertebrate mechanism that has been observed in humans, mice and fish. However, we do not understand how the host reduces pathobionts specifically, while leaving symbionts unaffected. In our previous research we demonstrated that T cells (specific immune cells) are involved in controlling pathobiont levels in zebrafish. This project aims to investigate how. We have preliminary evidence that neutrophils (innate immune cells) and/or epithelial cells (intestinal barrier cells) might play a role. By using the unique features of the zebrafish, we will be able to identify which mediators and cells are involved in pathobiont control, investigate the specificity of the response (are all pathobionts suppressed by the same or different mechanisms?). Since pathobionts reside in the lumen of the gut while the immune cells are present at a distance underneath the intestinal barrier, the question remains how mediators of the immune cells can reach and impact the luminal pathobionts. We hypothesize that the recently discovered extracellular vesicles might be involved. Extracellular vesicles are versatile cell-derived vesicles involved in intercellular communication. We will investigate whether vesicles containing pathobiont-reducing mediators travel to the gut lumen to repress the pathobionts. Understanding the mechanism of pathobiont control will open new treatment options (using the bodys natural response instead of antibiotic treatment) to combat disturbed microbial communities.