May 27, 2021

Japan researchers use soybean compound to make catfish 100% female

Researchers from Japan's Kindai University's Aquaculture Research Institute has succeeded in making catfish all female with a compound called isoflavone found in soybean, which is said to be a first in the country, The Mainichi reported.

The development promises to increase the production efficiency of catfish and other fish species whose females are more valuable than males as seafood.

The team based at the institute's Shingu Station in Shingu, Wakayama Prefecture, used isoflavone, a compound found in soybean similar in effect to female hormones, to create the all-female groups of catfish.

Though it has been known that administering female hormone turns male catfish into females, this method is banned for fish for human consumption.

According to team leader and aquaculture science associate professor Toshinao Ineno, as female catfish grow faster than males, by making them all female, production efficiency will rise and fewer male fish will be discarded. "This can be applied to other farm-raised fish whose females are more valuable," Ineno added. For example, his team intends to try making sturgeons — the fish that produce caviar — female using soybean isoflavone as well.

Technically, as the specific isoflavone, genistein, was used as the reagent in the experiment, the method is also prohibited in fish farming for human consumption. Ineno said, "In future, we'd like to think of methods in which catfish can take in soybean isoflavone in their food, such as soy lees."