Spent mushroom substrate explored as a fishmeal substitute in Japan

Rising costs, sustainability issues, and supply chain problems surrounding traditional fishmeal have pushed some Japanese researchers toward developing alternative sources of protein for use in aquaculture feed, including mushroom substrate.

Mushroom substrate is not the only alternative protein currently undergoing experimentation throughout Japan. Other options such as insects, single-cell organisms, and citrus byproducts are all increasingly popular deviations from traditional fishmeal that allow the fishing industry to promote sustainability and maintain the health of fish stocks.  

But thus far, the mushroom substrate has shown positive results in initial tests of its viability. A 2021 study by Malaysian scientists on the effects of feeding mushroom-based, pelleted feed to African catfish for 12 weeks, and more recently, a trial performed by a Japanese high school class, have found net benefits from using it as a substitute in aquafeed.

In the initial experiments at the high school, students involved in the marine production department fed red sea bream a one-to-one ratio mixture of SMS and conventional, fishmeal-based pellets for 34 days. The mix was well-accepted by the fish, aligning with other research previously conducted on SMS feed, the trial showed reduced mortality figures compared to traditional feed. However, growth was slower than with commercial feed. Assuming this was due to the naturally lower protein content of SMS, the class cooperated with Hokto to ferment the SMS for three months, which increased the protein content from 9.8 percent to 12.4 percent. They then repeated the trial production and achieved more favorable results.

The next step in the study entailed ... 

Photo courtesy of 88studio