In order to cater to market preferences, Japan has sex-changed male eels. From my personal point of view, I think it is undesirable.
As we all know, nature has its own rules. Changing the gender of animals artificially is definitely against the rules of nature. I really can’t figure out why, just because they want to increase the production of eels, Japanese fishery practitioners can actually come up with such a cool operation as male eels’ sex change, and they are also applying for a patent for this sex change technology.
This "denaturation" technology was developed by Japan's Aichi Prefecture Fisheries Testing Ground. In order to cater to consumer trends, ingredients similar to estrogen, "soy isoflavones", are mixed into fish bait. , causing the male eel to change into a female eel. Soy isoflavones are a biologically active substance, a type of secondary metabolite formed during the growth of soybeans. They are flavonoids that can be extracted from plants and have a similar structure to estrogen. Therefore, soy isoflavones are also called phytoestrogens.
Because the sex of an eel cannot be determined until its body length exceeds 30 centimeters, an ingredient similar to estrogen - soy isoflavones - was mixed into the bait at the test site, and the feeding method was adjusted. The results showed that after feeding eel fry in this way for a period of time, more than 90% of the male eels turned into females. Although Japan’s Pharmaceuticals and Medical Devices Act prohibits the use of estrogen in edible fish, it is said that there is no problem in adding soy isoflavones. However, whether there is a problem or whether it is harmful to the human body is not an immediate matter. It is not good to jump to conclusions now, but what can be confirmed is that forcibly changing the rules of nature is definitely going in the opposite direction. Even though eel fishing and production have decreased in recent years, and the market has greater demand for female eels, I believe that the vast majority of consumers will choose between "safe food" and "good taste". "Eating safely", I hope those aquatic industry practitioners will not rush for quick success and avoid shooting themselves in the foot.