Only males are born! ? From Nagasaki March 9 15:54 approaching amazing new technology

Tofugu is one of the representative tastes of winter.
Above all, the milt, which is the testis of a male, is attractive because of its rich taste.

A farming technique was developed in Nagasaki to sell this milt and raise its profile as a production area, and shipment began this season. Will the day come when the milt becomes familiar to us? (Nagasaki Broadcasting Station reporter Misato Yasui)

Where is the best tiger puffer producing area in the country?

From pufferfish to pufferfish, pufferfish to fried, grilled pufferfish, and rare parts of milt and fin liquor. Although it is hard to reach, it is a pufferfish dish that everyone wants to eat until they are full.

When asked about the locality of puffer fish in Osaka, which consumes the largest amount of puffer fish in Japan, Shimooseki and Yamaguchi were among the customers.

Certainly, Yamaguchi Prefecture has the highest volume of puffer fish in Japan. However, it is actually Nagasaki Prefecture when it comes to being the best “production area” in Japan.

The production of farmed puffer fish in Nagasaki Prefecture in 2018 is about 2,300 tons. It accounts for more than half of the national production. On the other hand, when it comes to natural puffer fish, Ishikawa Prefecture has the highest catch in Japan, but the same adult catches more than 800 tons.

In comparison, the scale of Nagasaki is different. Of the puffer fish restaurants in Osaka that we interviewed, we mainly deal with farmed trafugu from Nagasaki Prefecture. It is said that the reason is that they give good food and have good quality.

Focus on market value of "sea jewelry"

Nagasaki Prefecture, which produces a lot of puffer fish, is almost unknown to consumers nationwide.

A new technology developed to raise the profile of the locality is a unique technology that produces only male male pufferfish.

Males with milts, also called "sea jewels," are traded on the market at about 20% higher than females. We hope that if the milt is always included, it will be noticed in markets and other places.

Nagasaki Prefectural Fisheries Experimental Station Masaomi Hamazaki Senior Researcher

What is the mechanism for producing “all males”?

Then, what is the technology that produces male male troughfish "Zen-o"?

First, “spermatogonia”, which is the source of male sperm, is transplanted into the belly of a female fry. It grows not only eggs with the "X" sex chromosome, but also eggs with the male-specific "Y" sex chromosome.

Then, from the egg and the normal male sperm having the “X” or “Y” sex chromosome, a special “super male” having the “YY” sex chromosome with a quarter of the probability. Is born.

Furthermore, if this "YY" "super male" and "XX" ordinary female are multiplied together, all "XY" ordinary males "all males" will be born.

It took about 10 years from the start of research to the first shipment of this season.

Researcher Masaomi Hamasaki of the Nagasaki Prefectural Fisheries Research Institute, who developed this technology, says that he had the hardest time in the process of transplanting spermatogonia.

We adjusted the thickness of the needle in hundredths of a millimeter and repeated hundreds of experiments by changing the location, angle, and strength of the needle. In spring, the spawning season for puffer fish, she recalls that she had set a night in the lab.

Farmers also have high expectations

This winter, Dr. Hamasaki visited a farmer in Sasebo, Nagasaki Prefecture. This is for final confirmation for the first shipment.

Because traffugu is difficult to distinguish between males and females from their appearance, many judge their gender by touching their belly to check the tension of the testes.

I immediately floated in the sea, and when I picked up five tiger puffer fish at random and tried to judge them, they all contained a soft milt.

Fish farmer Kotaro Yamanouchi "I was at first wondering if they were all male, but I was really relieved to see them with my eyes.

Farmers ship large quantities of hundreds or thousands of fish to the market, so there is no need to separate males and females. Until now, shipping prices were determined mainly by weight. However, if it is a “all male” tortoise, it is expected to be treated at a high price from the shipping stage and directly increase the income of aquaculture companies.

Buyers in the largest consumer area, Osaka, are also paying attention

An annual fair held by the Prefectural Fisheries Association to promote the quality of farmed fish produced in Nagasaki Prefecture.

When we exhibited the "All Male" torchfish here, Akihiro Yoshimoto, a buyer in Osaka, the largest consumer area in Japan, noticed.

Akihiro Yoshimoto, Supermarket Chain Seafood Purchaser in Kansai “Shirako is very popular in the Kansai region.

When I was introduced to the supermarket chain store where Yoshimoto worked, a corner dedicated to torafugu was set up in one corner of the fresh fish counter.

This winter, we sold a new product that included a tiger sashimi sashimi, a fillet for a pot, and an albino luxurious ingredient.

Mr. Yoshimoto thought that if she purchased "Zen-o" trufflefish during the year-end and New Year season when demand for milt would peak, she would be able to stably obtain milt and increase the product lineup. We are now gathering colleagues' buyers and holding an in-house meeting, and we are considering ways to have them available next season.

Appeal Nagasaki's Torafugu with "All Males"

Nagasaki Prefecture plans to further increase the number of fish farmers that handle the “all male” tiger puffer fish.

Also, in addition to the merit of collecting distributors and retailers inside and outside the prefecture and making sure that milt is contained, "all males" having the same gene as ordinary males have "no problem with safety" etc. I will appeal to you.

Furthermore, if the supply of male tortoises increases in the future, the milt will not drop too much, and the Nagasaki Prefectural Fisheries Experimental Station will continue to collect data.

Nagasaki Prefectural Fisheries Experimental Station Masaomi Hamasaki Senior Researcher "I think that if general consumers can easily use milt, the consumption of torafugu will also increase. But not just consumers, but distributors. ''

Could Zeno be a trump card to raise the profile of Nagasaki as a pufferfish producing area? I want to continue reporting in the future.

Nagasaki Broadcasting Station Reporter Misato Yasui Joined in 2014 After working at Sendai Station, Nagasaki Station is in charge of local economy, etc. Shirako is a tempura group!