A research group led by Associate Professor Takayama Faculty of Science and Engineering has developed a budget-friendly supplement for promoting the growth of eels.Utsunomiya Campus

On Friday, September 12, 2025, Yuko Takayama, Associate Professor Department of Integrated Science and Engineering Faculty of Science and Engineering and Engineering, Teikyo University, and Takae Hirazawa, Associate Professor at the same department, in collaboration with Shigeaki Saito, Professor at the Institute of Molecular Life Sciences, Kurume University, developed a supplement for eels made from oil-producing yeast as an alternative to fish oil, which is traditionally used to promote growth.
Most eels currently on the market are farmed from glass eels, but the catch of glass eels is declining year by year and their prices are rising rapidly.Furthermore, eel feed, which is primarily made from fish meal, contains added fish oil to promote growth, but this separates out in the water, causing problems with water quality.
The eel supplement developed by this research group uses oil-producing yeast instead of fish oil. Oil-producing yeast has the unique property of storing large oil droplets made from neutral fats (triacylglycerols) within its own cells, which prevents them from separating from feed and polluting the water. In addition to oils, yeast also contains nutrients such as vitamins and minerals. When eels were fed feed containing oil-storing yeast as a supplement, their weight and girth increased rapidly, and a comparison of weight gain revealed that eels that ate oil-storing yeast (supplement yeast) grew approximately twice as fast as eels that ate yeast that did not store oils.
Feeding eels supplements made with oil-producing yeast will help them grow faster and produce meatier eels that can be shipped sooner. This shortens the time it takes to raise them and reduces the cost of feed and rearing, so if this environmentally friendly supplement becomes commercially viable, it is expected that we will be able to provide delicious, fatty eels that are easy on the wallet.

The results of this research were published in the monthly BIO INDUSTRY on Friday, September 12, 2025.

Press release here
For more information about Associate Professor Takayama, please click here.
For more information about Associate Professor Hirazawa, click here.

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