- Q: What is your current research topic?
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We are developing a technology to speed up breeding by applying fish surrogacy techniques. Specifically, we are working on research to have ultra-precocious rainbow trout, which mature in just six months, produce sperm from king salmon, which normally take four to six years to mature.
The background to this is the fact that the demand for seafood is currently increasing worldwide, and if this trend continues, overfishing will lead to a decline in natural resources. As a result, full-scale aquaculture is attracting attention as a way to ensure a stable supply of seafood.
Full-scale aquaculture is a cycle in which artificially hatched larvae are raised to parent fish, and then eggs are taken from the parent fish to create the next generation. This cycle is completely controlled by human hands, without relying on natural seedlings. However, full-scale aquaculture has problems such as many fish species being difficult to raise and the costs of feeding and raising them. To solve these problems, attention is being paid to breeding fish that are resistant to disease, grow quickly, and are delicious to eat.
Specifically, selective breeding is a technique that produces a population with the desired characteristics by repeatedly selecting and breeding fish with advantages such as delicious taste or fast growth over many generations. However, many farmed fish species take 2 to 5 years to reach maturity, which prevents the acceleration of selective breeding. Methods to shorten this generation time include controlling temperature and light conditions and administering hormones, which can produce individuals that mature quickly, but it is still not possible to significantly advance the maturity date.
Therefore, in the laboratory to which I belong, we developed a new technique called the surrogate parent technique as a technique to shorten the generation time. The surrogate parent technique is a technique in which reproductive stem cells, which are the source of eggs and sperm of a donor species, are transplanted into a related species, and the next generation derived from the donor is created from the surrogate parent. By applying this technique, sperm and eggs of fish that take a long time to mature can be produced in fish that mature in a shorter time, making it possible to shorten the generation time in breeding. However, it still takes one or two years to mature. Therefore, the theme of this research is to create a super-precocious fish that matures in a short period of six months, and use it as a dedicated host for the surrogate parent technique to construct a new rapid breeding method, which is a method to promote breeding. Data has already been obtained, and we have succeeded in obtaining sperm from king salmon, which take four to six years to mature, in just six months. If this technology is applied to breeding, it is expected that the time it took to create a new cultivated variety, which previously took nearly 1 years, can be shortened to just a few years, and that it will be possible to create cultivated varieties dramatically faster. - Q: What motivated you to start your research?
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I enjoyed the classes and practical training in the laboratory of Professor Goro Yoshizaki, who established the surrogate parent fish technique, and was attracted to the creativity of using the physiological functions of various fish and combining these functions to create new technologies, so I joined the laboratory. Professor Yoshizaki gave me this theme, and that's what got me started on this research.
- Q: What is interesting about your research?
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- As I try to solve problems with uncertain results using wisdom and ingenuity through trial and error, I get closer and closer to my goal. This trial and error process is very interesting. I've been in the Yoshizaki Laboratory for six years, but when I first joined, I had never been involved in experiments or research, so I started from scratch and had no idea what to do. I started my research by creating genetically modified rainbow trout, but of course it didn't go well at first, and I didn't get any good results for about half a year. I thought maybe I wasn't cut out for research after all, but after repeated experiments, I finally made a breakthrough and was able to create the experimental fish that were the core of the experiment. From there, the research got on track and has continued to this day.
- Q: What are some of the challenges of research?
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My research would not be possible without fish, so I had to think about how to raise the experimental fish so that they would not die. If they died, the experiment would stop and I would have to start over from making the fish again. If that happened, it would take about two years for the fish to grow, so I would not be able to graduate. I had to continue the experiment while raising and maintaining the fish healthy. It was really difficult to balance raising fish and research at the same time until I got used to it.
- Q: What kind of social impact can you expect from your research?
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- It takes about five generations to improve breeding. So, if the generation time is five years, it would take more than 5 years (5 x 5), but if I use the fish that I improved that mature in six months, it can be shortened to about three years (5 months x 25). In addition, it is possible to significantly reduce the costs of raising fish, such as food, tanks, and electricity. I think it is a truly groundbreaking technology in promoting breeding.
- Q: To which SDGs can your research contribute?
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- Goal 14: Conserve and sustainably use the oceans. We can produce fish with better characteristics more quickly than with natural resources. I think we can contribute to conserving marine resources and using them in a sustainable way.
- Q: Were there any people or events that influenced you when you decided to enroll at Tokyo University of Marine Science and Technology?
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- I had been playing in the ocean since I was a child and had a vague interest in marine life. As I progressed to junior high and high school, I learned about the interesting characteristics and physiological functions of marine life through general education and biology classes, and my interest in biology grew. I wanted to go to a university where I could learn about marine life from a physiological perspective, so I applied to this university.
- Q: What is good about choosing Tokyo University of Marine Science and Technology?
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Even if you study marine life, you need other knowledge. At our school, you first learn general knowledge about the ocean, and then as you go up through the grades, you specialize in what you're interested in. I think it's good that you can learn a wide range of knowledge about the ocean.
In addition to classroom learning, there is a lot of practical training, so students can learn through real-life experiences at sea. I think that is one of the strengths of our school. - Q: Why did you decide to go to graduate school?
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- Of course, the research was interesting, but I started by introducing a gene I designed myself into eggs to create genetically modified rainbow trout, and finally saw some good results, but I graduated before I could compile them into a paper. Rather than handing the research over to my juniors, I wanted to write a paper myself and publish it to the world, so I decided to continue to a doctorate.
- Q: Please tell us about your dreams, goals, and the career you are aiming for in the future.
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- I want to stay in academia. I am currently doing research under Professor Yoshizaki, but I would like to go to a laboratory overseas and do a postdoctoral research. I don't have a specific idea of ??what kind of research I want to do, but I would like to broaden my horizons and be able to think from multiple angles, so I would like to gain experience abroad in order to do that.
- Please give a message to those (applicants) who are considering going on to a master's (doctoral) program.
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- There are obstacles and worries about going on to a doctoral course, such as finances, age, and life plans, but there are scholarships available now, so I think it's a good idea to take advantage of them to continue on to doctoral course. If you enjoy your research, you should be brave and go for it.
