DISSERTATION RESEARCH: Is richer always better? Testing the biotic resistance hypothesis in ornamental fish microbiomes

生活在宿主上和宿主中的微生物的总和被称为“微生物组”。宿主的微生物组通常比宿主本身具有更多的细胞和功能，并在营养，健康和疾病中发挥重要作用。抗生素治疗会破坏小鼠和人类的微生物组，并增加治疗后细菌感染的可能性。鱼类依赖于它们的微生物组，在商业环境中经常用抗生素治疗，特别是沿着观赏贸易路线，供应商必须向零售宠物商店提供无病产品。这项研究将测试抗生素是否会在运输过程中干扰鱼类微生物组，从而降低鱼类到达零售商店水箱后的抗病能力。研究人员将与伍兹霍尔教育项目合作，让代表性不足的群体参与实验室研究。此外，研究人员将继续与观赏鱼行业成员进行合作，让私营部门参与以科学为基础的疾病解决方案。这项研究将为微生物群在水产养殖疾病和潜在益生菌治疗中的作用提供有价值的见解，并有助于推进水产养殖发展的科学解决方案。抗生素治疗通常伴随着生物耐药性的降低，或保护宿主免受外部病原体定植和增殖的能力的降低。本研究的第一个目的是评估抗生素对鱼类微生物组抗病性的影响，使用实验室中的水族馆实验。将模拟使用和不使用抗生素的观赏鱼运输，随后是已知鱼类病原体的峰值。生物抗性将通过死亡率和鱼类微生物组内加标病原体的相对丰度来衡量。在人类和小鼠模型中，抗生素治疗后用高丰度微生物群落重新接种可恢复生物抗性。这项研究的第二个目标是测试一系列细菌接种物在抗生素治疗后恢复鱼类微生物组生物抗性的能力。这些接种物的丰富度和组成各不相同，生物抗性将如上所述进行评估，同时评估微生物组丰富度。研究人员将测试一种假设，即代表各种抗病机制的益生菌物种的低丰度恢复接种物将提供最强的微生物组介导的生物抗性。

The sum of microorganisms living on and in a host is called the "microbiome". A host's microbiome often has more cells and functions than the host itself, and plays important roles in nutrition, health and disease. Antibiotic treatment disrupts microbiomes in mice and humans and increases the likelihood of bacterial infections after treatment. Fish depend on their microbiome and are often treated with antibiotics in commercial settings, particularly along ornamental trade routes where suppliers must deliver a disease-free product to retail pet shops. This study will test if antibiotics have the unintended consequence of disturbing fish microbiomes during shipment, thereby reducing disease resistance after fish have arrived in retail store tanks. The researchers will collaborate with the Woods Hole Partnership in Education Program to involve underrepresented groups in the laboratory research. Additionally, the researchers will continue ongoing collaborations with ornamental fish industry members, engaging the private sector in science-based solutions to disease. This research will provide valuable insight into the role microbiomes play in aquaculture diseases and potential probiotic treatments, and contribute to the advancement of science-based solutions to aquaculture development. A reduction in biotic resistance, or the ability to protect the host from colonization andproliferation of external pathogens, often accompanies antibiotic treatments. The first aim of this research is to assess the influence of antibiotics on disease resistance in fish microbiomes, using aquarium-based experiments in the laboratory. Ornamental fish shipments with and without the use of antibiotics will be simulated, followed by a spike of a known fish pathogen. Biotic resistance will be measured by mortality, and the relative abundance of the spiked pathogen within fish microbiomes. In humans and mouse models, re-inoculation after antibiotic treatment with a high-richness microbial community restores biotic resistance. The second objective of this research will be to test a range of bacterial inoculates for their ability to restore biotic resistance in fish microbiomes after antibiotic treatment. These inoculates will vary in their richness and composition, and biotic resistance will be assessed as above, alongside resulting microbiome richness. The researchers will test the hypothesis that a low-richness recovery inoculum of probiotic species representing a variety of disease resistance mechanisms will provide the strongest possible microbiome-mediated biotic resistance.