2024-09-10

Infectious diseases pose the biggest threat to fish farming! To address this issue, associate Professor Liang-Chun Mark Wang from the Department of Marine Biotechnology and Resources at National Sun Yat-sen University (NSYSU) established the Marine and Pathogenic Microbiology Laboratory in Asia. His research team studied the tripartite interaction between the fish skin, mucus microbiome, and environment, setting an unprecedented discovery that the microbiome on the fish skin mucus has resistance and healing abilities, which serve as part of fish immunity and can help defend against pathogens in the environment. The research products not only assist the aquaculture economy but are also expected to be used in other aquaculture organisms, thus showing the promising application prospects of bionic technology and potentially new medical drugs. The innovative research won him the 2024 Ta-You Wu Memorial Award.

The relationship between the fish skin, mucus microbiome, and environment is a complex and dynamic interaction combination. Currently, only a single-digit number of laboratories worldwide focus on aquatic biological bacteria and are devoted to tripartite causal research between the dynamics of fish microbiome, environment, and host. Wang's research team is currently the only one in Taiwan across Asia working in this field. Wang pointed out that due to the scarcity of literature on the subject, even experimental methods are required to start from scratch. He led his team to devote two years of research and development using 3D printing to produce the world's first ex vivo fish skin model. This model composes the skin epidermis - the mucosa epithelia that simulate the defense against enemies, and the skin dermis - the connective tissue that provides foundation and nutrients for the epidermis. Hence, this model can realistically replicate how fish skin mucus microbiome coexists by providing a sterile test platform to examine the impact of different pathogens in the environment on the health of fish skin.

The research team took the large economic and scaleless catfish of Southeast Asia as the main research object and is also extending to economically significant fish species in southern Taiwan, such as groupers, milkfish, and seabass. The team's discovery on the microbiome on the fish skin mucus generates useful information in aquaculture practice, helping fish adapt to the environment thereby reducing diseases. However, when the concentration of pathogens in the environment gradually increases and exceeds the mucus microbiome's protecting limitation, the protective effect will gradually lose. Additionally, diseased fish also have the opportunity to rely on the healing power of the mucosal microbiome to recover and even produce microbiome-associated immunity, which greatly extends the lifespan and survival rate of fish.

"This so-called probiotic mechanism of fish skin microbiome can be applied in many aspects," Wang stated. By analyzing the composition and characteristics of the microbiome, the team can improve the pathogen-resistance and healing abilities of fish and unveil the secrets to fish health and immune balance, helping aquaculture farmers reduce the use of medication and protect the environment. In addition, different fish species have various resistance levels to pathogens. For instance, the skin mucus of milkfish has particularly strong resistance to the invasion of pathogens in the environment, giving a hypothesis of strong skin mucus microbiome resistance and further refining and developing new practices for aquaculture fish or even applying to humans. Besides, different water environments can also render the same fish skin different mucus microbiome along with the health status of the fish, indicating a need for establishing a data database. "We hope researchers could just scrape a sample of fish skin mucus to check the state of the microbiome and then knowing the fish health without sacrificing any fish lives," Wang says. "It aligns more with the spirit of animal conservation and promotes the development of new non-invasive health monitoring models in the aquaculture field."

Wang is not only a professor but also an alumnus of NSYSU's Department of Marine Biotechnology and Resources. He pursued his PhD in Cell Biology & Molecular Genetics at the University of Maryland College Park, USA. After graduation, he served as an Assistant Clinical Professor at the same university in the Microbiology Department, where his research focused on the development of human ex vivo and in vitro models. After returning to Taiwan in 2019, he joined his alma mater, NSYSU, devoting himself to Host-Pathogen interaction, Mucosal microbiome in teleost fish, Aquatic bacterial infection & mechanisms, and Antibiotic resistance research fields. To better explore the local aquaculture diseases, Wang led the team to go outdoors and visit local fish farmers as well as their ponds to understand the industry and ongoing diseases. Moreover, Wang also teamed up with the Kaohsiung City Animal Protection Office to co-author a book on the prevention and control of aquaculture infectious diseases in Kaohsiung. In 2021, a massive death of Suckermouth catfish occurred in Lianchihtan (Lotus Pond). The team immediately explored and researched the pathogen and successfully isolated the causative pathogenic bacteria. His multidisciplinary research in skin, mucus microbiome, and environment in both fish and humans now branched into medical-related technologies and was recognized by the 2024 Ta-You Wu Memorial Award.