The objective of this proposal is to understand changes induced in the gut microbial community and on the host responses by nanoparticles (NPs). The overall hypothesis is that ingestion of nanomaterials, especially those that have anti-microbial properties, will change the microbiome (the community of microorganisms that share the body space) of trout resulting in adverse health outcomes. The investigators plan to investigate the changes in the microbiome resulting from the NP challenges, hypothesizing that these changes would lead to immunosuppression and increased opportunity for pathogen infection. The hypothesis will be tested with a bacterial pathogen challenge. The results of this investigation will provide new insights into the impact of NPs on the gut microbiome, which will have relevance not just for trout, but for humans and other organisms as well, since these fundamental host-microbiome interactions are conserved across all vertebrates. The data obtained from the proposed investigations can also be helpful for both industry and regulators as industry formulates new NPs with lower toxicity or regulators look to reduce exposure of humans and wildlife to NPs. The proposal includes excellent outreach and training of graduate and undergraduate students, as well as the involvement of high school students, in research. The research results can potentially guide regulatory agencies.
The model used will be the environmentally relevant and commercially significant rainbow trout, Oncorhynchus mykiss. The investigators will use high throughput sequencing to understand the changes in the microbiome, specifically, the effects of dietary exposure to NPs will be determined by global genomic sequencing of the microbial communities and quantitative PCR to target specific microbial species. Changes in abundance of the specific microbes will be evaluated among treatments and over time. In the same fish, gene expression profiling will be conducted to identify biomarker genes that respond to alterations in the microbial community composition. A subset of NP treatments will be selected to conduct longer-term exposure in fish that will subsequently be exposed to Y. ruckeri and the outcome of this bacterial challenge will be evaluated.
