In fish and shrimp aquaculture, diet and microbial dysbiosis as well as stress and pathogenic infection are common triggers of intestinal inflammation, leading to impaired growth and increased mortality. Probiotic or nutritional interventions have been proposed as safe and effective means to promote gut immune health and animal survival. The conserved innate immune system of the larval zebrafish makes it an excellent high-throughput model for identifying novel interventional strategies. Here, we report a rapid, semi-automated pipeline for identifying compounds that are sufficient to rescue intestinal inflammation triggered by two independent mechanisms: chemical-induced colitis and high-fat diet-induced microbial dysbiosis. As a proof-of-concept, we demonstrate that Aloe Vera extract is able to rescue both modes of inflammation, with additional screening of nutritional compounds ongoing. Overall, our platform will support the rapid discovery of novel nutritional supplements which can promote intestinal health and immunity in aquaculture.
We have developed a custom pipeline using the larval zebrafish model to rapidly screen for anti-inflammatory nutritional interventions (Fig. 1). Using a transgenic line fluorescently labeling neutrophils (Tg(mpx:GFP)), we subjected zebrafish either to 4-hr chemical inflammation by 2,4,6-Trinitrobenzenesulfonic acid (TNBS), or a 24-hr high-fat chicken egg yolk diet, both of which promote rapid intestinal neutrophil accumulation. We also developed a custom FIJI macro for semi-automated quantification of intestinal neutrophil numbers. Using overnight antibiotic (ABEM) treatment, we show that only the latter (diet-induced inflammation) is dependent on the gut microbiome (Fig. 2A). Consistent with reports in the literature, a 2-hr aloe vera extract feeding is sufficient to rescue both modes of inflammation (Fig. 2B), suggesting effects on convergent inflammatory pathways downstream of microbial dysbiosis. Screening of additional compounds and pre/probiotics is ongoing, along with further characterisation of the role of the microbiome in gut inflammation.